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SUGANO KojiGraduate School of Medicine / Department of Medical Device EngineeringProfessor
Research activity information
■ Award- Jan. 2023 The Institute of Electrical Engineers of Japan, Special Issue on World State-of-the-art Research on Sensors and Micromachines Best Paper Award, Fabrication of Tri-Axial MEMS Tactile Sensor for Minimally Invasive Medical Application using Wafer-Level Packaging
- Apr. 2022 34th International Microprocesses and Nanotechnology Conference (MNC2021), Young Author’s Award, Characterization of nanogap with gold nanoparticle dimer controlled by four-point bending for electrical and optical single molecule measurement
- Nov. 2019 電気学会, 第36回「センサ・マイクロマシンと応用システム」シンポジウム 優秀ポスター発表賞, 光励起ナノギャップ電極を用いたDNAオリゴマーの光トラップおよび1分子検出
- Oct. 2017 電気学会, 第34回「センサ・マイクロマシンと応用システム」シンポジウム 奨励賞, 単一金ナノ粒子二量体を用いた表面増強ラマン分光によるDNAオリゴマー1分子検出Japan society
- Jan. 2017 電気学会, 平成28年電気学会優秀論文発表（IEEJ Excellent Presentation Award）, 金ナノ粒子二量体配列を用いたDNA塩基の高感度・高速表面増強ラマン分光Japan society
- Oct. 2016 電気学会, 第33回「センサ・マイクロマシンと応用システム」シンポジウム 優秀技術論文賞, 金ナノロッド構造を用いた光熱変換によるレーザ波長計測マイクロ振動子デバイスJapan society
- Oct. 2015 電気学会, 第32回「センサ・マイクロマシンと応用システム」シンポジウム 優秀ポスター賞, 金ナノ粒子二量体配列を用いたDNA 塩基の表面増強ラマン分光Japan society
- Oct. 2015 電気学会, 第32回「センサ・マイクロマシンと応用システム」シンポジウム 奨励賞, 金ナノ粒子直線状配列を用いた表面増強ラマン分光の特性評価
- Jan. 2015 電気学会, 平成26年電気学会優秀論文発表（IEEJ Excellent Presentation Award）, 金粒子配列ナノ流路を用いた表面増強ラマン分光分析デバイスJapan society
- Oct. 2014 電気学会, 第31回「センサ・マイクロマシンと応用システム」シンポジウム 最優秀技術論文賞, 金ナノ粒子二量体の規則的配列構造による高感度表面増強ラマン分光Japan society
- Institute of Electrical Engineers of Japan (IEE Japan), Jan. 2023, IEEJ Transactions on Sensors and Micromachines, 143(1) (1), 13 - 18, English[Refereed]Scientific journal
- Abstract The effect of surface potential on the carrier mobility and piezoresistance of core–shell silicon carbide nanowires (SiC NWs) was investigated to realize small and sensitive SiC-microelectromechanical systems sensors. The p-type cubic crystalline SiC (3C-SiC) NWs were synthesized via the vapor–liquid–solid method and coated with silicon dioxide (SiO2) or aluminum oxide (Al2O3) dielectric shells to form core–shell structured NWs with different surface potentials. Four-point bending devices (FBDs) with a field-effect transistor (FET) configuration integrating a single core–shell 3C-SiC NW as the FET channel were fabricated to apply an additional electric field and strain to the core–shell 3C-SiC NWs. The fixed oxide charge densities of the SiO2 and Al2O3 shells showed positive and negative values, respectively, which were equivalent to electric fields of the order of several hundred thousand volt per centimeter in absolute values. In the core–shell 3C-SiC NWs with originally low impurity concentrations, the electric field induced by the fixed oxide charge of the shells can determine not only the electrical conduction but also the charge carriers in the NWs. Bending tests using the FBDs showed that the piezoresistive effect of the SiO2-coated NW was almost the same as that of the as-grown 3C-SiC NW reported previously, regardless of the gate voltage, whereas that of the Al2O3-coated NW was considerably enhanced at negative gate voltages. The enhancement of the piezoresistive effect was attributed to the piezo-pinch effect, which was more pronounced in the NW, where the carrier density at the core–shell interface is enhanced by the electric field of the dielectric.IOP Publishing, Sep. 2022, Nanotechnology, 33(50) (50), 505701 - 505701, English[Refereed]Scientific journal
- Microresonator-based optical sensing has been reported to achieve a high measurement resolution of near-infrared light intensity. The light intensity was measured from the resonant frequency shift with the thermal stress of a silicon doubly clamped beam. In this study, the beam length and vibration amplitude were considered as parameters for improving the measurement resolution. This study investigates the effect of these parameters on the sensitivity (resonant frequency shift per light intensity) and the quality factor (Q factor) to estimate the measurement resolution, considering the thermomechanical noise as the fundamental limitation. The result of the measurement indicated that the longer the resonator, the greater the shift in the resonant frequency. The Q factor is considered to be constant regardless of the resonator beam length. Although the vibration amplitude was increased until nonlinear vibration occurred, no change in the sensitivity and Q factor was observed. The light intensity measurement resolution was calculated using a theoretical equation based on the experimental tendencies. The device with the longest beam length of 800 µm and the gold nanostructured absorber had the highest resolution. The light intensity measurement resolution was improved with a longer beam length and larger vibration amplitude.Corresponding, Apr. 2022, Microsystem Technologies, English[Refereed]Scientific journal
- Jan. 2022, Japanese Journal of Applied Physics, EnglishIntegration of silicon nanowire bridges in microtrenches with perpendicular bottom-up growth promoted by surface nanoholes[Refereed]Scientific journal
- Various nanostructures for single-molecule surface-enhanced Raman spectroscopy (SERS) have been fabricated through a random aggregation process using nanoparticles that can stochastically generate multiple hotspots in the laser spot. This leads to multiple molecule detection. In this study, a single gold nanoparticle (AuNP) dimer with a single hotspot was fabricated in a laser spot controlling the position and orientation on a silicon substrate using a nanotrench-guided self-assembly. The Raman peaks of deoxyribonucleic acid (DNA) were dynamically observed, indicating a single DNA oligomer detection composed of adenine, guanine, cytosine, phosphate, and deoxyribose.2022, Optics Letters, 47(2) (2), 373 - 376, English[Refereed]Scientific journal
- The widespread of near-infrared spectroscopes in the consumer field is expected to create new demand, such as the detections of fruit and vegetable rot and the easy measurement of the amount of water in the skin. Conventional cooled photodiodes using compound semiconductor materials such as InGaAs have problems with cost reduction and miniaturization. Therefore, we proposed an electrostatic Si microresonator device for the realization of a near-infrared optical sensor. This device measures the resonance frequency shift caused by the thermal stress generated in the resonator due to light absorption depending on the light intensity. The purpose of this study is to apply the device to near-infrared spectroscopy of water as a photodetector. We proposed an evaluation method based on a theoretical equation and confirmed that the device could detect the near-infrared absorption spectrum of water. The measurement results of the developed device matched well with that of the commercially available photodiode intensity sensor. In the future, it is expected that a compact near-infrared spectrometer with high sensitivity and low cost will be realized by arranging devices that integrate absorbers with different wavelength dependencies.Corresponding, Wiley, Dec. 2021, Electronics and Communications in Japan, 104(4) (4), e12340, English[Refereed]Scientific journal
- The widespread of near-infrared spectroscopes in the consumer field is expected to create new demand, such as the detections of fruit and vegetable rot and the easy measurement of the amount of water in the skin. Conventional cooled photodiodes using compound semiconductor materials such as InGaAs have problems with cost reduction and miniaturization. Therefore, we proposed an electrostatic Si microresonator device for the realization of a near-infrared optical sensor. This device measures the resonance frequency shift caused by the thermal stress generated in the resonator due to light absorption depending on the light intensity. The purpose of this study is to apply the device to near-infrared spectroscopy of water as a photodetector. We proposed an evaluation method based on a theoretical equation and confirmed that the device could detect the near-infrared absorption spectrum of water. The measurement results of the developed device matched well with that of the commercially available photodiode intensity sensor. In the future, it is expected that a compact near-infrared spectrometer with high sensitivity and low cost will be realized by arranging devices that integrate absorbers with different wavelength dependencies.Corresponding, Institute of Electrical Engineers of Japan (IEE Japan), Sep. 2021, IEEJ Transactions on Sensors and Micromachines, 141(9) (9), 321 - 326, Japanese[Refereed]Scientific journal
- As a plasmonic absorber for short-wavelength infrared hyperspectral imaging, a silicon-coated gold nanodiffraction grating structure is proposed. This plasmonic absorber leads to absorption peaks in short-wavelength infrared region by the high refractive index of silicon coating on gold grating. It is relatively easy to fabricate with smaller size than those of already known absorbers. By performing fabrication, simulation, and measurement, we demonstrate the sharp absorption peaks of short-wavelength infrared light using only 400-1000 nm grating interval. We believe this miniaturized absorber will be able to be applied to hyperspectral imaging without a spectroscope owing to its sharp absorption peak at a specific wavelength.Corresponding, The Optical Society, Aug. 2021, Journal of the Optical Society of America B, 38(10) (10), 2863 - 2872, English[Refereed]Scientific journal
- The influence of shallow surface nanoholes on the growth direction of silicon nanowires (SiNWs) with the vapor-liquid-solid (VLS) process was studied in order to realize a single-step way to promote integration of high-density SiNWs along a specific direction. Shallow surface nanoholes were formed by the short-Time metal-Assisted chemical etching (MACE) process with catalytic Au nanoparticles of 60 nm also used for the VLS process, in order to shape nanoholes with a similar diameter to the nanoparticles. With an increase in MACE processing time to 5 min, the ratio of perpendicularly grown SiNWs to the SiNWs that appeared on the (111) silicon surface significantly increased in the initial growth phase, reaching higher than 80%. This ratio was more than 3 times higher than without the MACE process. On the other hand, the excess processing time brought about a decrease of the SiNWs detected. This result indicated that the formation of surface nanoholes with an appropriate depth could be an effective way of controlling SiNW growth direction.IOP Publishing, May 2021, Japanese Journal of Applied Physics, 60(5) (5), 055502 - 055502, English[Refereed]Scientific journal
- The dynamic motion of DNA oligomers at the nanoscale gap between nanoelectrodes is measured under plasmonic excitation using laser irradiation. The use of a nanogap enables highly sensitive detection of individual molecules using an electrical readout or an optical readout such as Raman spectroscopy. However, the target molecule must reach the nanogap in order to be detected. This study focuses on the use of plasmonic excitation to trap molecules at the nanogap surface. The nanogap electrode is fabricated by electromigration and is, therefore, a much smaller nanogap than the top-down fabrication in the conventional plasmonic trapping studies. To demonstrate the individual molecule detection and to investigate the molecular behavior, the molecules are monitored using an electrical readout under a bias voltage instead of an optical readout used in the conventional studies. The conductance change due to DNA oligomer penetration to the nanogap is observed with the irradiated light intensity of over 1.23 mW. The single-molecule detection is confirmed irradiating the laser to the nanogap. The results suggest that DNA oligomers are spontaneously attracted and concentrated to the nanogap corresponding to the detection point, resulting in high detection probability and sensitivity.Corresponding, IOP Publishing, Mar. 2021, Nano Express, 2(1) (1), 010032 - 010032, English[Refereed]Scientific journal
- This study developed a small, three-axis force sensor with a 3D microstructure for installation into a robot gripper. The sensor was manufactured by high-temperature punch creep-forming of 5 μm thick single-crystal silicon (Si) cantilevers during an impurity diffusion process for piezoresistors. The punch creep-forming could achieve a large out-of-plane deformation of the Si cantilevers within a small area. The punch creep-forming simulations were conducted for designing the 3D formed force sensor based on the creep constitutive equation for a 5 μm thick Si film at 1050 °C. Consequently, this study succeeded in fabricating a 3D formed force sensor with a 320 μm diameter hemispheric structure by punch creep-forming without breaking the structure. The force sensor was set on a printed circuit board and packaged using urethane resin. The viscoelastic response of the resin-packaged sensor was evaluated by conducting stress-relaxation (SR) tests and dynamic mechanical analysis, and characterized by a five-element generalized Maxwell model (GMM). In the SR tests, the sensor output signal in the vertical direction showed a strong correlation with the displacement applied to the test, whereas that in the lateral direction was closely related to the load acting on the sensor. Numerical analyses based on the GMM could estimate the load and displacement acting on the sensor from its output signal.IOP Publishing, Feb. 2021, Journal of Micromechanics and Microengineering, 31(2) (2), 025009 - 025009, English[Refereed]Scientific journal
- Piezoresistive effects of core-shell silicon carbide (SiC) nanowires (NWs) were experimentally evaluated using a FET-type device with single SiC nanowire as a channel, by electrical resistivity measurement with changing gate voltages. The I-V characteristics with no straining showed change in FET behaviors from n-channel type to p-channel type by changing insulating shell from SiO to AlO due to the fixed charge in the shells. An influence of initial surface potential determined with the fixed charge in the insulating shells and gate voltages on the resistance change ratio at a small strain of SiCNWs was experimentally evaluated. Gauge factors at 1 % small strain of SiCNW differed from -21 to 40 between SiO-shell and AlO-shell SiCNWs due to the polarity of the fixed charge in the shells, and increased from 40 to 100 on AlO-shell SiCNW with a negative voltage increment from 0 to -0.5 V.IEEE, Jan. 2021, 2021 IEEE 34th International Conference on Micro Electro Mechanical Systems (MEMS), 2021-January, 848 - 851, English[Refereed]International conference proceedings
- This study presents a micromechanical resonator to detect near-infrared (NIR) laser wavelength shifts for dense wavelength division multiplexing (DWDM) systems. A feedback control of laser wavelength detecting the wavelength shift is required to keep a spacing of adjacent wavelength channel. The conventional detection method with an etalon filter has the detectable limit of wavelength shift. In this regard, we integrate a micromechanical resonator with plasmonic gold nanorod structures to produce the optical absorption change due to the wavelength shift. The wavelength shift can be detected via the resonant frequency shift based on the thermal stress change in the resonator. The gold nanorod array is fabricated on a gold thin film and subsequently covered by a Si thin film, which is used for controlling the refractive index of the surrounding medium. This causes absorption peaks of plasmonic resonance to be generated in the NIR region. We develop a theoretical equation for the relative resonant frequency that is in proportion to the laser intensity and the beam length cubed. The experimental tendency of relative resonant frequency shifts is observed to be in good agreement with the theoretical equation. The maximum relative resonant frequency shift is 69 Hz/nm, whereas the resolution is estimated to be 0.37 pm, taking into account the thermomechanical noise. Therefore, the fabricated resonator is confirmed to be useful for measuring the laser wavelength with high resolution for large-capacity DWDM systems.Elsevier BV, Sep. 2020, Sensors and Actuators A: Physical, 315, 112337 - 112337, English[Refereed]Scientific journal
- © 2020, Springer-Verlag GmbH Germany, part of Springer Nature. Near-infrared (NIR) imaging has been used for nondestructive and non-contact inspections in various areas, such as food and medicine inspections and medical diagnoses. The short-wavelength infrared light (SWIR) sensor currently used requires a Peltier cooler and a diffraction grating spectroscope owing to its detection principle. Thus, realizing a low-cost and miniaturized SWIR imaging device remains challenging and has limitations for practical applications. In this study, we propose a bolometer-type detector element fabricated using a silicon-on-insulator (SOI) wafer as a low cost and miniaturized SWIR image sensor element. We adopted gold (Au) nanowire grating structures coated with silicon as wavelength-dependent SWIR absorbers and aimed at wavelength-selectivity imaging without using a spectroscope. A device was designed and fabricated with Au nanowire grating structures on a doubly clamped Si beam using microelectromechanical system (MEMS)) technology. The electrical characteristics of the device were measured depending on device temperature and SWIR irradiation intensity. It was found that electrical resistance decreased linearly with increasing device temperature and SWIR irradiation intensity (wavelength at 1530 nm), as semiconductors have negative temperature coefficients of resistance. The results show similar trends from both finite element method (FEM) analysis and theoretical calculation. The resistances at wavelengths ranging from 1530 to 1565 nm at 5 nm increment were evaluated. It was confirmed that absorber-integrated bolometer device enabled wavelength-dependent response of the resistance according to the absorption spectrum.Corresponding, Aug. 2020, Microsystem Technologies, 27(3) (3), 997 - 1005, English[Refereed]Scientific journal
- In this study, we investigated the effect of the resonator beam shape on the thermal stress and the resonance frequency change when providing heat to the resonator beam by near-infrared laser irradiation. This investigation provides crucial data for optical and heat sensing application using microresonators. The microresonator beam with an optical absorber for near-infrared region was fabricated, varying the numbers of beams and corners. When irradiating the optical absorber with a laser, the resonant frequency decreased. It is because the photothermal effect provides compressive stress in the beam, resulting in resonant frequency decrease. The resonant frequency change rate increased with decreasing the number of beams. According to the analytical results, we confirmed that the analytical thermal stress determined the resonant frequency change rate in the same beam length. The corner remarkably decreased the resonant frequency change rate. The straight beams bend to the orthogonal direction by the thermal expansion of another straight part of the beam, resulting in deformation of the beam in the axial direction. Therefore, the reaction force and compressive stress in the axial direction reduces.Corresponding, IOP Publishing, Jun. 2020, Japanese Journal of Applied Physics, 59(SI) (SI), SIII04 - SIII04, English[Refereed]Scientific journal
- For applications of plasmonic structures to high performance sensors in the near-infrared region, the structures require narrowband absorption peaks, good controllability of absorption peak position, and easy fabrication process. Multiple patterns with different absorption peaks should be integrated on the same substrate. In addition, polarization independence is desired for cost reduction and miniaturization of devices. In this study, we fabricated the Si-deposited gold nano-grating structures, the wire and concentric ring structures. Then their absorption spectra were evaluated. The peak wavelength shifted to longer wavelength with increasing the pitch of the grating structure and the thickness of Si. It was revealed that the peak was greatly shifted changing the thickness of Si. In the wire structures and the concentric ring structures, polarization dependence and polarization independence of peak absorption were observed, respectively. By using the Si-deposited gold nano-grating structures, wide control of the peak wavelength was realized in the near infrared region.Corresponding, Institute of Electrical Engineers of Japan (IEE Japan), Apr. 2020, IEEJ Transactions on Sensors and Micromachines, 140(4) (4), 72 - 78, Japanese[Refereed]Scientific journal
- This paper reports a surface enhanced Raman spectroscopy (SERS) of a single-stranded DNA toward SERS-based DNA sequencing. The Raman enhancing hotspot with 1-nm nanogap in the single dimer of gold nanoparticles has a space for only single DNA oligomer and enables measurements of a single nucleobase. Optimizing gold nanoparticle size, we demonstrated the detection of a single adenine in a single DNA oligomer. The time transition of adenine and cytosine peaks reflects identification of adjacent bases in a DNA oligomer sequence, suggesting the possibility of one-by-one DNA sequencing with SERS.IEEE, Jun. 2019, 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII), 979 - 982, English[Refereed]International conference proceedings
- This paper demonstrates the manipulation of DNA oligomers with 16 adenine molecules using plasmonic nanogap structure. The optical excitation caused plasmonic dielectrophoresis or/and thermophoresis of molecules to the nanogap due to huge gradient of an electric field. We confirmed the single-molecule electrical measurement using the nanogap electrodes irradiated by a He-Ne laser. We considered that the DNA oligomers were transported to the nanogap resulting in conductance change. We classified the changes in the current as step- or spike-like signals. The histogram of the stagnation time shows the peak at around 22 ms. We were able to detect the behavior of DNA oligomers.Corresponding, IEEE, Jun. 2019, 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII), 166 - 169, English[Refereed]International conference proceedings
- This study evaluated the mechanical properties and piezoresistivity of core-shell silicon carbide nanowires (C/S-SiCNWs) synthesized by a vapor-liquid-solid technique, which are a promising material for harsh environmental micro electromechanical systems (MEMS) applications. The C/S-SiCNWs were composed of a crystalline cubic (3C) SiC core wrapped by an amorphous silicon dioxide (SiO x ) shell; however, TEM observations of the NWs showed that hexagonal polytypes (2H, 4H , and 6H) were partially induced in the core by a stacking fault owing to a Shockley partial dislocation. The stress-strain relationship of the C/S-SiCNWs and SiC cores without an SiO x shell was examined using MEMS-based nanotensile tests. The tensile strengths of the C/S-SiCNWs and SiC cores were 7.0 GPa and 22.4 GPa on average, respectively. The lower strength of the C/S-SiCNWs could be attributed to the SiO x shell with the surface roughness as the breaking point. The Young's modulus of the C/S-SiCNWs was 247.2 GPa on average, whereas that of the SiC cores had a large value with scatter data ranging from 450 to 580 GPa. The geometrical model of the SiC core based on the transmission electron microscopy observations rationalized this scatter data by the volume content of the stacking fault in the core. The piezoresistive effects of the C/S-SiCNW and SiC core were also evaluated from the I-V characteristics under uniaxial tensile strain. The gauge factor of -30.7 at 0.008 ϵ for the C/S-SiCNW was approximately two-times larger than that of -15.8 at 0.01 ϵ for the SiC core. This could be caused by an increase of the surface state density at the SiO x /SiC interface owing to the positive fixed oxide charge of the SiO x shell.Apr. 2019, Nanotechnology, 30(26) (26), 265702, English[Refereed]Scientific journal
- Mar. 2019, 実験力学, 19(1) (1), 24 - 29, Japanese単層カーボンナノチューブのMEMS引張試験における顕微ラマン分光によるひずみ計測[Refereed]Scientific journal
- Jan. 2018, International Journal of Automation Technology, 12(1) (1), 79 - 86, EnglishNanotemplate-guided self-assembly of gold nanoparticles and its application to plasmonic bio/chemical sensing[Refereed][Invited]Scientific journal
- Jan. 2018, The 31st IEEE International Conference on Micro Electro Mechanical Systems (MEMS2018), 1036 - 1039, EnglishA Novel 3-axis Tiny Tactile Sensor Developed by 3-D Microstructuring using Punch Creep Forming Process[Refereed]International conference proceedings
- In this study, single-molecule detection on a prefabricated substrate through surface-enhanced Raman spectroscopy (SERS) with 4,4'-bipyridine molecules was achieved. The use of a substrate with directionally arrayed gold nanoparticle dimers was proposed for the single-molecule detection and identification of a wide range of bio/chemical molecules. Around 50 Raman measurements and statistical analyses were performed to demonstrate a single-molecule SERS. At 10%(-11) M, the distribution was fitted by three Gaussian curves, whereas the distribution of Raman intensities was fitted by one Gaussian curve at 10%(-5) M. The probability of molecule detection is consistent with the Poisson distribution. This result indicates the possibility of detecting 0, 1, and 2 molecules. Thus, we confirmed that the developed substrates achieved single-molecule SERS detection and identification. (C) 2017 The Japan Society of Applied Physics.IOP PUBLISHING LTD, Jun. 2017, JAPANESE JOURNAL OF APPLIED PHYSICS, 56(6) (6), 06GK01, English[Refereed]Scientific journal
- Corresponding, Jun. 2017, The 19th International Conference onSolid-State Sensors, Actuators and Microsystems (Transducers2017), 468 - 471, EnglishSERS Detection and Analysis of a Single Oligomer using a Single Gold Nanoparticle Dimer[Refereed]International conference proceedings
- Jun. 2017, The 19th International Conference on Solid-State Sensors Actuators and Microsystems (Transducers2017), 1245 - 1248, EnglishDry Etching and Low-Temperature Direct Bonding Process of Lithium Niobate Wafer for Fabricating Micro/Nano Channel Device[Refereed]International conference proceedings
- In this paper, a characterization method for Raman enhancement for highly sensitive and quantitative surface-enhanced Raman spectroscopy (SERS) is reported. A particle dimer shows a marked electromagnetic enhancement when the particle connection direction is matched to the polarization direction of incident light. In this study, dimers were arrayed by nanotrench-guided self-assembly for a marked total Raman enhancement. By measuring acetonedicarboxylic acid, the fabricated structures were characterized for SERS depending on the polarization angle against the particle connection direction. This indicates that the fabricated structures cause an effective SERS enhancement, which is dominated by the electromagnetic enhancement. Then, we measured 4,4'-bipyridine, which is a pesticide material, for quantitative analysis. In advance, we evaluated the enhancement of the particle structure by the Raman measurement of acetonedicarboxylic acid. Finally, we compared the Raman intensities of acetonedicarboxylic acid and 4,4'-bipyridine. Their intensities showed good correlation. The advantage of this method for previously evaluating the enhancement of the substrate was demonstrated. This developed SERS characterization method is expected to be applied to various quantitative trace analyses of molecules with high sensitivity. (C) 2017 The Japan Society of Applied Physics.IOP PUBLISHING LTD, Jun. 2017, JAPANESE JOURNAL OF APPLIED PHYSICS, 56(6) (6), 06GK03, English[Refereed]Scientific journal
- Corresponding, Mar. 2017, Electronics and Communications in Japan, 100(4) (4), 33 - 41, EnglishSurface-Enhanced Raman Spectroscopy Analysis Device with Gold Nanoparticle Arranged Nanochannel[Refereed]Scientific journal
- SURFACE-ENHANCED RAMAN SPECTROSCOPY ANALYSIS OF DNA BASES USING ARRAYED AND SINGLE DIMER OF GOLD NANOPARTICLEThis paper reports an ultrasensitive surface-enhanced Raman spectroscopy (SERS) for detecting and identifying four kinds of DNA bases: adenine, cytosine, thymine, and guanine using a gold nanoparticle dimer. The gold nanoparticle dimer was directionally arrayed on a substrate in order to achieve huge enhancement according to the polarization-dependent enhancement. 10-11 M limit of detection for four DNA bases and 0.1 s rapid detection for adenine were achieved. Additionally, a separated single dimer was fabricated and evaluated. We clarified single-molecule-level SERS detection and identification was possible using the locally enhanced single hotspot of the single dimer with the 1-nm nanogap.Corresponding, IEEE, 2017, 30TH IEEE INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS 2017), 408 - 411, English[Refereed]International conference proceedings
- MICRORESONATOR WITH GOLD NANOROD ARRAY FOR LASER WAVELENGTH MEASUREMENT BY PHOTO-THERMAL CONVERSIONIn this study, we developed the resonator-based sensor device for measurement of laser wavelength changes in a wavelength division multiplexing (WDM) system for large capacity transmission. Laser light is absorbed into the gold nanorod array on the resonator beam, which has wavelength dependent absorption, resulting in temperature change of the beam. Therefore the wavelength change can be measured from resonant frequency shift. We observed the large resonant frequency shift when changing the laser wavelength. The shift was proportional to a cube of beam length and a laser power according to the developed equation. The maximum shift and resolution were 68.8 Hz/nm and 0.29 pm, respectively.IEEE, 2017, 30TH IEEE INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS 2017), 159 - 162, English[Refereed]International conference proceedings
- This paper reports on the effect of oxidation on fracture behavior of single crystal silicon (SCS). SCS specimens were fabricated from (100) silicon-on-insulator wafer with 5-pm thick device layer and oxide layer were thermally grown. Quasi-static tensile testing of as-fabricated, oxidized and oxidized layer removed specimens was performed. The fracture origin location transited from the surface to silicon/oxide interface and inside of silicon. The transition may be caused by surface smoothing, thickening oxide layer and formation of oxide precipitation defects in silicon during oxidation. The radius of the oxide precipitation defects was estimated, which is well agreed with the fracture-initiating crack sizes. (C) 2015 Elsevier Ltd. All rights reserved.PERGAMON-ELSEVIER SCIENCE LTD, Sep. 2016, ENGINEERING FRACTURE MECHANICS, 163, 523 - 532, English[Refereed]Scientific journal
- This study focuses on the development of a multi-walled carbon nanotube (MWCNT) forest integrated micromechanical resonator working as a rarefied gas analyzer for nitrogen (N2) and hydrogen (H2) gases in a medium vacuum atmosphere. The resonant response is detected in the form of changes in the resonant frequency or damping effects, depending on the rarefied gas species. The carbon nanotube (CNT) forest on the resonator enhances the effective specific surface area of the resonator, such that the variation of the resonant frequency and the damping effect based on the gas species increase significantly. We developed the fabrication process for the proposed resonator, which consists of standard micro-electro-mechanical systems (MEMS) processes and high-density CNT synthesis on the resonator mass. The high-density CNT synthesis was realized using multistep alternate coating of two types of ferritin proteins that act as catalytic iron particles. Two devices with different CNT densities were fabricated and characterized to evaluate the effect of the surface area of the CNT forest on the resonant response as a function of gas pressures ranging from 0.011 to 1 Pa for N2 and H2. Considering the damping effect, we found that the device with higher density was able to distinguish N2 and H2 clearly, whereas the device with lower density showed no difference between N2 and H2. We confirmed that a larger surface area showed a higher damping effect. These results were explained based on the kinetic theory of gases. In the case of resonant frequency, the relative resonant frequency shift increased with gas pressure and surface area because of the adsorption of gas molecules on the resonator surfaces. Higher density CNT forest adsorbed more gas molecules on the surfaces. The developed CNT forest integrated micromechanical resonator could successfully detect N2 and H2 gases and distinguish between them under pressures of 1 Pa.Institute of Physics Publishing, Jun. 2016, Journal of Micromechanics and Microengineering, 26(7) (7), 075010, English[Refereed]Scientific journal
- Corresponding, Jun. 2016, 電気学会論文誌（センサ・マイクロマシン部門誌）, 136(6) (6), 256 - 260, Japanese金ナノ粒子二量体配列を用いたアデニン分子の高感度表面増強ラマン分光検出[Refereed]Scientific journal
- Jan. 2016, Journal of Microelectromechanical Systems, 25(1) (1), 188 - 196, EnglishTime-Resolved Micro Raman Stress Spectroscopy for Single Crystal Silicon Resonator using MEMS Optical Chopper[Refereed]Scientific journal
- MEMS-BASED MECHANICAL CHACTERIZATION OF CORE-SHELL SILICON CARBIDE NANO WIRES FOR HARSH ENVIRONMENTAL NANONIECHANICAL ELEMENTSThis research clarified mechanical properties of core-shell silicon carbide nanowires (C/S-SiCN Ws) grown by a vapor-liquid-solid (VSL) technique, using newly developed Electrostatically Actuated I\Anotensile Testing devices (EANATs). The C/S-SiCNWs consist of a crystalline cubic silicon carbide (3C-SiC) core with < 111 > axis wrapped by an amorphous SiOx shell. The stress-strain relations for individual C/S-SiCNWs and 3C-SiCNWs without the SiOx shell have been successfully obtained from the nanotensile tests using EANATs. Young's modulus of the C/S-SiCNWs was 247.2 GPa whereas that of the 3C-SiCNWs showed a quite different value of 498 GPa on average. The tensile strengths for C/S- and 3C-SiCNWs also showed 7.0 GPa and 22.4 GPa on average, respectively, which are enough huge values as a structural material of MEMS/NEMS.IEEE, 2016, 2016 IEEE 29TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS), 543 - 546, English[Refereed]International conference proceedings
- Electrical Resistance Characterization of Strain-Induced Multiwalled Carbon Nanotubes Using MEMS-Based Strain Engineering DeviceIn this research, we clarified the electrical resistance change and mechanical properties of strain induced multiwalled carbon nano tubes (MWCNTs), synthesized by atmospheric chemical vapor deposition (CVD), using a MEMS-based strain engineering device mounted on an in situ scanning electron microscopy (SEM) nanomanipulation system. The Young's modulus of an individual MWCNT and its shear strength during interlayer sliding deformation were estimated from the load displacement curve. The electrical resistance of the MWCNT was 215 kW without strain, while an anomalous electrical resistance change was observed under a large strain. The resistance change ratio was almost 0 during the interlayer sliding of the MWCNT, but it specifically showed a sharp increase at the end of the sliding in spite of the MWCNT not breaking mechanically. Molecular dynamics (MD) simulations provided us with a reasonable suggestion that the hard sticking with an atomic reconfiguration at the edge of the outer layer of the MWCNT induces the sharp increase in electrical resistance before the mechanical breaking of the MWCNT.MYU, SCIENTIFIC PUBLISHING DIVISION, 2016, SENSORS AND MATERIALS, 28(2) (2), 75 - 88, English[Refereed]Scientific journal
- This study achieved single molecule detection, for the first time, on the prefabricated substrate for SERS (surface-enhanced Raman spectroscopy) with non-resonant molecules. Single-molecule SERS has never been achieved using the prefabricated SERS substrate. It has been achieved only using molecule bridged particle dimer by in-liquid formation with polarization matching of incident light. In this study the substrate with directionally arrayed gold nanoparticle dimers was proposed for single molecule detection and identification of a wide range of bio/chemical molecules. Around 50 Raman measurements and statistical analysis were performed for demonstrating single-molecule SERS. At 10(-5) M, the distribution of Raman intensities were fitted by one Gaussian curve. At 10(-11) M, the distribution was fitted by three Gaussian curves. That is consistent with a Poisson distribution. This indicates the probability of detecting 0, 1, and 2 molecule(s). From these results, we confirmed that the developed substrates achieved single molecule SERS detection and identification.ELECTROCHEMICAL SOC INC, 2016, MICROFABRICATED AND NANOFABRICATED SYSTEMS FOR MEMS/NEMS 12, 75(17) (17), 3 - 10, English[Refereed][Invited]International conference proceedings
- This Letter investigates the effect of crystallographic orientation on tensile fractures of silicon microstructures. Specimens 5 m wide and 5 m thick were fabricated on (100) and (110) wafers with 100, 110, and 111 tensile axes. To explore the effects of different surface orientations and morphologies, these specimens were patterned from (100) and (110) silicon-on-insulator (SOI) wafers using the Bosch process under identical fabrication conditions, while other specimens were fabricated from (110) wafers under different conditions. Tensile tests of specimens prepared under the identical fabrication conditions showed that (100) specimens had lower strength than (110) specimens along the 100 and 110 axes; the average strength decreased from 3.62 to 3.14 GPa for 110. This decrease in strength is related to differences in damage that ultimately causes fractures. While (110) specimens fractured due to fabrication damage at top corners, fractures of (100) specimens were due to pit-like defects on bottom surfaces. Since these defects were introduced during SOI bonding processes, the fractures of (100) specimens were dominated by intrinsic SOI defects rather than damage introduced during specimen fabrication processes. To realise higher-strength structures on SOI wafers, both the damage caused during fabrication and the intrinsic defects need to be controlled.INST ENGINEERING TECHNOLOGY-IET, Dec. 2015, MICRO & NANO LETTERS, 10(12) (12), 678 - 682, English[Refereed]Scientific journal
- This paper reports the fabrication technique for chain-like arrangements of gold nanoparticles on a substrate and its optical characterization. We successfully fabricated the directional chain-like arrangements and controlled the particle number by the self-assembly using nanotrench templates. We fabricated the dense arrangement in the nanotrenches with high yield reducing an electrostatic repulsive force between particles in water suspension by an addition of electrolytes. Extinction spectra showed the shift of spectrum peaks depending on the particle number, which was consistent with the analytical results.Institute of Electrical Engineers of Japan, Nov. 2015, IEEJ Transactions on Sensors and Micromachines, 135(11) (11), 474 - 475, Japanese[Refereed]Scientific journal
- Nov. 2015, 電気学会論文誌（センサ・マイクロマシン部門誌）, 135-E(11) (11), 433 - 438, Japanese高感度表面増強ラマン分光分析に向けた マイクロ流路内粒子凝集反応解析[Refereed]Scientific journal
- Nov. 2015, 電気学会論文誌（センサ・マイクロマシン部門誌）, 135-E(11) (11), 474 - 475, Japaneseナノテンプレートを用いた金ナノ粒子直鎖配列の作製と光学特性評価[Refereed]Scientific journal
- Jul. 2015, Journal of Micromechanics and Microengineering, 25(8) (8), 084003, EnglishHigh-speed Pulsed Mixing in a Short Distance with High-frequency Switching of Pumping from Three Inlets[Refereed]Scientific journal
- A micro/nanofluidic device containing linearly arranged gold nanoparticles embedded in nanochannels was developed for highly sensitive surface-enhanced Raman spectroscopy (SERS). The Si nanochannel array was fabricated using a photolithography-based process. Synthesized colloidal particles of mean diameter 100 nm were arranged linearly in the nanochannels, using a nanotrench-guided self-assembly process. The particle geometry provides significant Raman enhancement by matching the polarization direction of the incident light to the connection direction of the particles. The SERS spectrum was obtained from 1 mM 4,4′-bipyridine solution using the fabricated micro/nanofluidic SERS device. The directionally arranged particles showed the same polarization angle dependency as the simulated result. The molecule was detected from 10 pM solution using the particle arrangement. We confirmed that the particle arrangement was appropriate for highly sensitive SERS.Corresponding, Institute of Electrical Engineers of Japan, Jun. 2015, IEEJ Transactions on Sensors and Micromachines, 135(6) (6), 214 - 220, Japanese[Refereed]Scientific journal
- A micro/nanofluidic device containing linearly arranged gold nanoparticles embedded in nanochannels was developed for highly sensitive and highly efficient surface-enhanced Raman spectroscopy (SERS). The Si nanochannel array was fabricated using a photolithography-based process. The nanochannel width was controlled from 100 to 400 nm. Synthesized particles of mean diameter 100 nm were arranged linearly in the nanochannels, using a nanotrench-guided self-assembly process. We developed a process for integrating linearly arranged nanoparticles and micro/nanofluidic components. The particle geometry provided significant Raman enhancement. Furthermore, efficient Raman analysis was possible by scanning a laser spot, because the particles were arranged in one direction. The fabricated structures were evaluated for SERS using 4,4′-bipyridine molecules at concentrations of 1 mM and 10 µM. The Raman peaks was obtained from a few hot spots. The Raman spectra showed that the molecule-specific Raman intensities were correlated with the number of hot spots in the nanochannel.Institute of Physics, May 2015, Japanese Journal of Applied Physics, 54(6S1) (6S1), 06FL03, English[Refereed]Scientific journal
- ULTRASENSITIVE SURFACE-ENHANCED RAMAN SPECTROSCOPY USING DIRECTIONALLY ARRAYED GOLD NANOPARTICLE DIMERSThis paper reports an ultrasensitive nanostructure for surface-enhanced Raman spectroscopy (SERS). The gold nanoparticle dimer, which has been reported as the highest Raman enhancing structure, was directionally arrayed on a substrate for the first time. The highest enhancement can be achieved when a particle connection direction of a dimer is matched to polarization direction of incident light. Therefore the huge enhancement can be achieved at all dimers in total. Optimizing the dimer arrangement, 10 pM limit of detection and 0.5 s rapid detection were achieved.IEEE, 2015, 2015 28TH IEEE INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS 2015), 608 - 611, English[Refereed]International conference proceedings
- ANOMALOUS RESISTANCE CHANGE OF ULTRASTRAINED INDIVIDUAL MWCNT USING MEMS-BASED STRAIN ENGINEERINGThis research clarified the anomalous electric resistance change of ultrastrained multi-walled carbon nanotube (MWCNT), as well as its mechanical properties, using the Electrostatically Actuated NAnotensile Testing device (EANAT) mounted on the in-situ SEM nanomanipulation system. The Young's modulus of MWCNT and its shear stress during interlayer sliding deformation were estimated from the load-displacement curve. The electrical resistance of the MWCNT was 215 k. without strain, which was similar to the previously reported value, however the anomalous resistance change was observed under enormous strain. Although the resistance change ratio was almost constant during interlayer sliding of the MWCNT, it specifically showed a sharp raise at the end of the sliding in spite of the MWCNT not breaking mechanically. The molecular dynamics (MD) simulation provided a good understanding that the atomic reconfiguration due to the hard sticking at the edge of extracted outer layer of MWCNT might induce the sharp raise of resistance without its mechanically breaking. This result reported here is extremely important for reliability of MWCNT interconnects.IEEE, 2015, 2015 28TH IEEE INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS 2015), 369 - 372, English[Refereed]International conference proceedings
- The effect of in- and anti-phase mode decoupling on the frequency response of coupled in-plane resonators was examined, experimentally, to suppress the acceleration sensitivity (acceleration output) in tuning fork gyroscopes (TFGs). Finite element simulations, conducted in our recent works, show that the origin of acceleration sensitivity for the sensing resonators in TFGs lies in the transduction of linear (in-phase) acceleration to anti-phase resonant vibration of the sensing resonators in TFGs. We further revealed that the frequency decoupling of the in- and anti-phase vibration modes is effective in suppressing the transduction. To experimentally validate this, two types of coupled resonators (one coupled with a frame and the other with a spring) to represent the sensing resonators of TFGs were fabricated on silicon-on-insulator wafer. Different resonant frequencies were used to evaluate the frequency decoupling effect on the coupled resonators, i.e., the coupling from in-phase mode oscillation to the anti-phase mode vibration. The vibration amplitude of the anti-phase mode increased in the coupled resonators with small frequency decoupling (decoupling ratio, DR) value. Additionally, the two types of coupled resonators exhibit similar output after considering the effect of decoupling ratio, anti-phase frequency and different stiffness unbalances. Our results reveal that TFG can be designed with lower acceleration sensitivity by utilizing sense resonators with large decoupling ratio, higher anti-phase frequency, and possessing structures which are insensitive to fabrication imperfections.SPRINGER, Mar. 2014, MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS, 20(3) (3), 403 - 411, English[Refereed]Scientific journal
- An alkali metal vapor cell is a crucial component of the highly sensitive Chip Scale Atomic Magnetometers (CSAMs) that are increasingly deployed in a variety of electronic devices. Herein, we propose a novel microfabrication technique utilizing an array of microchannels at a bonded interface, to enable gas feedthrough for evacuation of unwanted gases from a vapor cell and subsequent introduction of an inert gas, followed by permanent sealing of the microchannels by reflow of a glass frit. The characteristics of glass frit reflow are analyzed to investigate the feasibility of using microchannels formed either on a silicon substrate, or embedded in a glass frit layer, with four different cross-sectional shapes considered. Prior to modeling the microchannels for simulation, the minimum cross-sectional size of a microchannel that fulfills gas feedthrough requirements was calculated and a value of 10 mu m was determined based on a flow conductance model. The sealing of the microchannels was simulated using the finite element method (FEM) and the results revealed that flow resistance is a crucial design factor. Thus, embedded microchannel designs were more suitable for the proposed sealing technique than microchannel designs fabricated in silicon.SPRINGER, Mar. 2014, MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS, 20(3) (3), 357 - 365, English[Refereed]Scientific journal
- FABRICATION OF GOLD NANOPARTICLE-EMBEDDED NANOCHANNELS FOR SURFACE-ENHANCED RAMAN SPECTROSCOPYA micro/nanofluidic device including linearly-arranged gold nanoparticles embedded into nanochannels was developed toward highly-sensitive Surface-Enhanced Raman Spectroscopy (SERS) of multicomponent analysis with low background signal. The nanochannels array was fabricated by a "photo" - lithography-based process without costly and time-consuming process such as an electron beam lithography and a focused-ion-beam etching. Then particles with diameters of 100 nm are linearly arranged into the nanochannels by a nanotrench-guided self-assembly process followed by microchannel fabrication for introducing solutions. The device was successfully fabricated and it was evaluated for SERS. The fabricated structure was active for SERS analysis with 4,4'-bypiridine as a target molecule.Corresponding, IEEE, 2014, 2014 IEEE 27TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS), 1059 - 1062, English[Refereed]International conference proceedings
- DIRECT MEASUREMENT OF SHEAR PIEZORESISTANCE COEFFICIENT ON SINGLE CRYSTAL SILICON NANOWIRE BY ASYMMETRICAL FOUR-POINT BENDING TESTThis research evaluated the shear piezoresistance property of p-type single crystal silicon nanowire (SiNW) by the asymmetrical four-point bending (AFPB) technique proposed by the authors [1]. We fabricated the p-type SiNW on the AFPB test specimen with "V"-shaped notches (V-notches) made of single crystal silicon. Bending the specimen by the asymmetrical four point-supports, simple shear stress can be produced at the center of the specimen. Consequently, we have succeeded in evaluating the shear piezoresistance coefficient of SiNW directly, which was found to be pi(44)=203 x 10(-11) Pa-1 at an impurity concentration of 7.3 x 10(18) cm(-3). This value is 2.1 times larger than that of p-type piezoresistors used in conventional piezoresistance sensors on a micrometer scale. The proposed evaluation technique and obtained result will be effective for design application of high-sensitivity mechanical sensors integrating SiNW piezoresistance elements.IEEE, 2014, 2014 IEEE 27TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS), 600 - 603, English[Refereed]International conference proceedings
- Vibration coupling in out-of-plane resonators was investigated to design low acceleration sensitivity tuning fork gyroscopes (TFGs) of out-of-plane sensing axis type. Numerical and theoretical analysis was carried out on a spring-coupled translational x-axis TFG. The vibration coupling was controlled by separating the in-phase mode ( fin) from anti-phase mode ( fanti). The theoretical and numerical analysis showed that the acceleration sensitivity is inversely proportional to decoupling ratio, whereas the angular rate sensitivity does not change by keeping the fanti constant. For experimental verification, we designed four types of coupled resonators and fabricated them from SOI wafer: two of them are frame-coupled and the other two are spring-coupled. In each coupling type, one adopted a translational resonator and the other adopted a torsional resonator. The measured anti-phase vibration amplitude against in-phase oscillation decreased by weakening coupling which agreed with the numerical analysis. As decoupling ratio (=( fin - fanti)/ fanti) of the spring-coupled translational resonator increased from 0.09 to 0.29, the anti-phase vibration amplitude in the analysis and measurement decreased to 28% and 51%, respectively.Institute of Electrical Engineers of Japan, 2014, IEEJ Transactions on Sensors and Micromachines, 134(12) (12), 392 - 399, English[Refereed]Scientific journal
- Sep. 2013, Journal of Micromechanics and Microengineering, 23(11) (11), 115003, EnglishOn-chip Fabrication of Alkali-Metal Vapor Cells utilizing an Alkali-Metal Source Tablet[Refereed]Scientific journal
- Aug. 2013, 電気学会論文誌E（センサ・マイクロマシン部門誌）, 133(8) (8), 320 - 329, JapaneseMEMSネガレジストの粗視化分子動力学シミュレーション[Refereed]Scientific journal
- Jun. 2013, Proceedings of The 17th International Conference on Solid-State Sensors Actuators and Microsystems (Transducers2013), 1807 - 1810, EnglishSERS characterization based on silver nanoparticle dimer in microfluidic laminar flow for molecule trace detection[Refereed]International conference proceedings
- Jun. 2013, Proceedings of The 17th International Conference on Solid-State Sensors Actuators and Microsystems (Transducers2013), 1946 - 1949, EnglishEffect of surface morphology and crystal orientations on fracture strength of thin film (110) single crystal silicon[Refereed]International conference proceedings
- A novel sealing technique using sacrificial microchannels was proposed for control of an atmosphere in a micromachined alkali metal vapor cell for a chip-scale atomic magnetometer. The microchannels act as a feedthrough connecting the cell to the outside atmosphere during evacuation and gas filling steps, and eventually they are sealed by glass-frit reflow. A silicon microchannel was designed and sealing by glass-frit reflow was successfully demonstrated in reflow experiments. Simulation results clarified the glass-frit reflow characteristics and their dependence on cross-sectional shapes of the microchannels. Hermeticity of the proposed sealing technique at a leak rate of less than 10-12 Pa·m3/s was verified by a high-resolution helium leak test. © 2013 Wiley Periodicals, Inc.May 2013, Electronics and Communications in Japan, 96(5) (5), 58 - 66, English[Refereed]Scientific journal
- A new integration technique of Deoxyribonucleic acid (DNA) origami as an excellent platform to arrange various nanomaterials such as metallic nanoparticles, carbon nanotubes and proteins and so on with nanometer scale resolution into MEMS utilizing DNA hybridization of a complementary pair of single-strand DNAs (ssDNAs) was demonstrated. A contact-mode atomic force microscopy (AFM) based lithography was adopted to form ssDNA modified patterns into an organic thin film with 30 nm resolution on a silicon substrate. A newly designed DNA origami (30 nm × 150 nm) with ssDNA as sticky ends was successfully fixed at specific positions of the substrate by DNA hybridization. © 2013 IEEE.Apr. 2013, Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), 307 - 310
- This paper reports on a newly developed coarse-grained molecular dynamics simulation for epoxy-based chemically-amplified photoresist dedicated to MEMS. To analyze photoresists material properties, Kremer-Grest model (bead-spring model) with an extended angle bending potential was newly employed. A uniaxial elongation simulation and the molecular diffusion simulation were performed to analyze the dependence of an elastic modulus and a molecular permeability on the cross-linked ratio of a photoresists, since these characteristics are important for a permeable membrane made of photoresist to control biological molecules diffusion in biomedical applications. The simulated dependencies of the elastic modulus and the molecular permeability on the cross-linked ratio of photoresists showed good correspondences with the experimental results. This suggests a photoresists membrane can be used as a molecular permeable membrane with controllable permeability by varying photolithography process parameters. © 2013 The Institute of Electrical Engineers of Japan.2013, IEEJ Transactions on Sensors and Micromachines, 133(8) (8), 1 - 329, Japanese[Refereed]Scientific journal
- We report the effects of surface damage and crystal orientation on fracture strength of single crystal silicon (SCS) by means of tensile test using electrostatic-force grip. The specimens of three major crystal orientations fabricated from (110) SOI wafer were characterized with different surface morphologies prepared by the specimen patterning process. Our specimen patterning process was composed of Bosch process and wet etching process for surface residue removal. We changed processing time and sequence of the two processes to get different surface morphologies. As result of uni-axial tensile test of 9 types of specimens (length: 120 μm, width: 5 μm, thickness: 5 μm), i.e. specimens of 3 crystal orientations with 3 different surface morphologies, improvement of surface morphology doubled average tensile strength: e.g. < 110> strength varied from 1.8 GPa to 3.6 GPa, while average tensile strength difference among crystal orientations was less than 20 % on each fabrication conditions. The fracture surfaces mainly consisted of (111) plane. We found tensile fracture characteristics of 3 crystal orientations: in < 100> specimens the fracture origin location changed by the fabrication conditions, while < 110> and < 111> specimens respectively showed quantitative relationships between surface morphology and tensile strength common to different fabrication conditions. These results are beneficial for tensile strength prediction from surface morphology. © 2013 The Japan Society of Mechanical Engineers.2013, Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 79(804) (804), 1191 - 1200, Japanese[Refereed]International conference proceedings
- The mechanical properties of an epoxy-based chemically amplified resists with various cross-linking ratios were simulated using a newly developed coarse-grained molecular dynamics simulation that employs a bead-spring model. Models with the different cross-linking ratios were created in the molecular dynamics calculation step and uniaxial elongation simulations were performed. The results reveal that the simulated elastic modulus of the resist modeled by the Kremer-Grest model with an extended angle bending potential depends on the cross-linking ratio, its dependency exhibits good agreement with that determined by nanoindentation tests. (c) 2012 Elsevier Ltd. All rights reserved.ELSEVIER SCI LTD, Sep. 2012, POLYMER, 53(21) (21), 4834 - 4842, English[Refereed]Scientific journal
- Compliance detection becomes very essential in minimally invasive surgery (MIS). It can help in detection of cancerous lumps and/or for deciding on tissue healthiness. In this paper, a micromachined piezoresistive tactile sensor, with two serpentine springs and 500-mu m cubic mesas, has been designed for detecting the compliance of soft tissue independent of the applied distance between the sensor and the tissue. The measuring range of the sensor is chosen to be associated with the soft-tissue properties. The sensor parameters are optimized to give high sensitivity and linearity of the sensor output. The design is simulated using ANSYS for checking the sensor performance. Then, the sensor is fabricated and tested by three types of specimens, namely, specimen chips with known stiffness, silicone rubber specimens, and chicken organ specimens (leg and heart). For the specimen chips and silicone rubber specimens, the sensor distinguished between different stiffnesses independent of the applied displacement in the range of 50-200 mu m. The sensor measured Young's modulus up to 808 kPa with an average error of +/- 7.25%. For the chicken leg and heart, the sensor distinguished between them under the applied displacement from 100 to 200 mu m, and they were calculated as 12 +/- 1 kPa and 81 +/- 8 kPa, respectively. [2011-0213]IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Jun. 2012, JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, 21(3) (3), 635 - 645, English[Refereed]Scientific journal
- The frequency response of in-plane coupled resonators is used for investigating the acceleration sensitivity of a MEMS tuning fork gyroscope (TFG) and a new method of suppressing the acceleration output is presented. The unbalancing of two sense resonators in the TFG caused by fabrication errors converted an external vibration into anti-phase mode excitation. To reduce the acceleration output, decoupling between in- and anti-phase modal frequencies [decoupling ratio (DR)] is crucial, since coupled resonators may cause large anti-phase vibrations from the acceleration. The acceleration output model was verified using two coupled resonators with 1 and 5 % stiffness unbalance. FEM simulation results showed a 25 % reduction in the anti-phase vibration by increasing the decoupling ratio from 0.09 to 0.29, irrespective of the coupled resonators designs. Quantitative analysis of a TFG based on coupled resonators with 1 % stiffness unbalance showed the acceleration output decreased from 5.65 to 1.43 deg/s/g.SPRINGER, Jun. 2012, MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS, 18(6) (6), 797 - 803, English[Refereed]Scientific journal
- In this paper, we report a test stand device for tensile testing nanoscale materials and its application to testing of a fullerene wire. We have developed an electrostatic microelectromechanical-systems tensile testing device which has a comb drive actuator to apply tensile force to a specimen and two capacitances for sensing the displacement to measure the elongation and applied force of the specimen. The force and displacement measurement resolutions have been demonstrated as 2 nN and 0.2 nm, respectively. A freestanding fullerene wire which was about 16 mu m long, 2 mu m wide, and 40 nm thick was integrated on the device, and the tensile testing of the wire was successfully demonstrated with nano-order resolutions. Measured Young's modulus and tensile strength of the wire were 5.9 GPa and 17 MPa, respectively. [2011-0257]IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Jun. 2012, JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, 21(3) (3), 523 - 529, English[Refereed]Scientific journal
- In this paper, we report on a method to assemble and clamp single walled carbon nanotubes (SWCNTs) mechanically and electrically on patterned electrodes for developing a new tensile testing method which achieves SWCNT mechanical characterization with high throughput. Electrical transport measurement on assembled SWCNTs was conducted in order to characterize clamping property. Theoretical analysis based on the obtained result reveals that the proposed mechanical clamp is sufficiently strong to conduct tensile testing of SWCNT. © 2012 The Institute of Electrical Engineers of Japan.Institute of Electrical Engineers of Japan, 2012, IEEJ Transactions on Sensors and Micromachines, 132(5) (5), 108 - 113, English[Refereed]Scientific journal
- We conducted uni-axial tensile test using electrostatic-force grip on thin film single crystal silicon of < 110> direction. The specimens were fabricated on (110) SOI wafer (length: 120 μm, width: 5 μm, thickness: 5 μm) and went through 3 different conditions of patterning process composed of Bosch process and wet etching process for surface residue removal. As a result, improvement of surface morphology brought increase of average tensile strength from 1.9 GPa to 3.6 GPa. SEM observation of fractured specimens suggests that, regardless of processing conditions, relationship between tensile strength and the top-view length of (110) crystal plane of specimens can be expressed with a common equation. © 2012 The Institute of Electrical Engineers of Japan.Institute of Electrical Engineers of Japan, 2012, IEEJ Transactions on Sensors and Micromachines, 132(9) (9), 320 - 321, Japanese[Refereed]Scientific journal
- 2012, 電気学会論文誌E（センサ・マイクロマシン部門誌）, 132-E(5) (5), 108 - 113, Japanese誘電泳動によりアセンブルしたSWCNTの無電解Auめっきによる機械的・電気的クランピング[Refereed]Scientific journal
- 2012, 電気学会論文誌E（センサ・マイクロマシン部門誌）, 132-E(9) (9), 320 - 321, Japanese加工条件の異なる(110)<110>単結晶シリコン薄膜の引張試験[Refereed]Scientific journal
- A novel sealing technique using sacrificial microchannels was proposed for atmosphere control in a micromachined alkali gas-filled cell for a chip scale atomic magnetometer. The microchannels act as feedthrough connecting the cell to outside atmosphere during evacuation and gas-filling steps, and eventually they are sealed by glass-frit reflow. Si microchannel dedicated as a sacrificial microchannel was proposed and its feasibility was successfully demonstrated by experiments. The simulation results clarified the glass-frit reflow characteristics and its dependence on cross-sectional shape of the microchannel. Hermeticity of the proposed sealing technique of less than 10 -12Pa·m3/s leak rate was verified by a high resolution helium leak test. © 2011 The Institute of Electrical Engineers of Japan.2011, IEEJ Transactions on Sensors and Micromachines, 131(7) (7), 251 - 257, Japanese[Refereed]Scientific journal
- 2011, International workshop on micro/nano-engineering, 12, 17 - 18, EnglishDesign of alkali metal vapor cell adapting sacrificial microchannel sealing technique[Refereed]
- 2011, 電気学会論文誌E（センサ・マイクロマシン部門誌）, 131-E(7) (7), 251 - 257, Englishチップスケール原子磁気センサのためのガラスフリットリフローによる犠牲マイクロ流路気密封止技術[Refereed]Scientific journal
- Fabrication of Gold Nanoparticle Pattern Using Combination of Self-Assembly and Two-Step TransferWe successfully demonstrated pattern formation of 60 nm gold nanoparticles using a highly productive combined technique of particle self-assembly and subsequent assembled particle pattern transfers. Dot and line patterns of nanoparticles were fabricated on a template substrate (SiO2/Si) utilizing template-assisted self-assembly (TASA). The obtained dot and line patterns of nanoparticles were transferred to a flexible poly-dimethylsiloxane (PDMS) substrate (the first transfer) and were subsequently transferred onto a gold thin film fabricated on a silicon substrate (the second transfer). We defined a yield of self-assembly as a ratio of the properly assembled area to the total dot-patterned area, and investigated the dependence of the yield on the experimental conditions such as the cross-sectional profiles of the template trench pattern, the concentration of the aqueous particle dispersion, and the cleaning process. It was confirmed that the yield is mainly governed by the width of the template trench. Under optimized conditions, a self-assembly yield of 79% was obtained. The flexible PDMS substrate was used for the first transfer step of the assembled particle pattern and an average yield of 58% was achieved. The second transfer yield onto the gold thin film was 93% using surface-activation bonding between the gold surfaces of the nanoparticles and the thin film. The developed process achieved high patterning accuracy and the misalignment of the dot pattern with the interval of 300 nm was 3.2% on average.MYU, SCIENTIFIC PUBLISHING DIVISION, 2011, SENSORS AND MATERIALS, 23(5) (5), 263 - 275, English[Refereed]Scientific journal
- Gold nanoparticles with diameters of a few tens of nanometer and a narrow size distribution were synthesized using a pulsed mixing method with a microfluidic system which consists of a Y-shaped mixing microchannel and two piezoelectric valveless micropumps. This mixing method enables control of the mixing speed of gold salts and reducing agent by changing the switching frequency of the micropumps, which was our focus to improve the particle size distribution, which is an essential parameter in gold nanoparticle synthesis. In the proposed method, the mixing time was inversely proportional to the switching frequency and the minimum mixing time was 95 ms at a switching frequency of 200 Hz. During synthesis experiments, the mean diameter of the synthesized gold nanoparticles was found to increase, and the coefficient of variation of particle size was found to decrease with decreasing mixing time. We successfully improved the coefficient of variation to less than 10% for a mean diameter of around 40 nm.SPRINGER HEIDELBERG, Dec. 2010, MICROFLUIDICS AND NANOFLUIDICS, 9(6) (6), 1165 - 1174, English[Refereed]Scientific journal
- This paper reports on a novel and simple 3-D fabrication technique of microstructures embedded in a single-layer negative resist. The proposed technique allows one the fabrication of an embedded microstructure with a single exposure and the subsequent development process. The unique feature of the proposed fabrication technique is the development method which enables the rapid fabrication of polymer-based microfluidic systems with relatively large areas but with micrometer-sized features. For example, features of microchannels, on the order of 100 mu m in width and 50 mm in length, sufficient for microfluidic systems, were successfully fabricated with a relatively short (< 20 min) development time. These features are realized by the interesting physical response of the top-membrane to the developer; the developer permeates through the top-membrane region made of semi-cross-linked photoresist, and the permeated developer dissolves the uncross-linked photoresist at the same time. As a step toward the practical use of the proposed development method, process parameter sets (exposure dose, postexposure bake (PEB) time, and temperature) related to the cross-linking reaction of the top-membrane region were investigated by employing the cross-linking reaction model describing the chemical reaction during the UV exposure and the PEB. Through a series of experiments, 1) a criterion of process parameter sets for the fabrication of centimeter-long embedded microchannels was obtained, and 2) the applicability to polymer-based microfluidic systems was successfully demonstrated.IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Oct. 2010, JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, 19(5) (5), 1058 - 1069, English[Refereed]Scientific journal
- The present paper describes a three-dimensional (3D) thick-photoresist microstructuring technique that exploits the effect of exposure wavelength on dissolution rate distributions in a thick-film diazonaphthoquinone (DNQ) photoresist. In fabricating 3D microstructure with specific applications, it is important to control the spatial dissolution rate distribution in the photoresist layer, since the lithographic performance for 3D microstructuring is largely determined by the details of the dissolution property. To achieve this goal, the effect of exposure wavelength on dissolution rate distributions was applied for 3D microstructuring. The parametric experimental results demonstrated (1) the advantages of the fabrication technique for 3D microstructuring and (2) the necessity of a dedicated simulation approach based on the measured thick-photoresist property for further verification. Thus, a simple and practical photolithography simulation model that makes use of the Fresnel diffraction theory and an empirically characterized DNQ photoresist property was adopted. Simulations revealed good quantitative agreement between the photoresist development profiles of the standard photolithography and the moving-mask UV lithography process. The simulation and experimental results conclude that the g-line (lambda = 436 nm) process can reduce the dimensional limitation or complexity of the photolithography process for the 3D microstructuring which leads to nanoscale microstructuring.IOP PUBLISHING LTD, Jun. 2010, JOURNAL OF MICROMECHANICS AND MICROENGINEERING, 20(6) (6), 65005 (pp.1 - 13), English[Refereed]Scientific journal
- In this paper, we report on a component modeling of in-plane 2DOF comb transducer for equivalent circuit analysis of electrostatic MEMS. The proposed model does not depend on connected components such as voltage sources, external forces, and springs since the model contained a dummy spring that can detect the comb displacement in itself. Using the model, we can analyze not only small-signal ac response but also dc operating points which means that once the parameters are calculated for a comb transducer, we need not to change the model parameters by changing any connected components. This model was adapted to a 2DOF SOI resonator and the measured frequency responses agreed well with the simulated responses. © 2010 The Institute of Electrical Engineers of Japan.2010, IEEJ Transactions on Sensors and Micromachines, 130(9) (9), 5 - 449, Japanese[Refereed]Scientific journal
- In this study, we fabricated the microreactor which enables to control mixing speed and reaction temperature since their conditions are considered as essential parameters for chemical reduction method of gold nanoparticle synthesis. The microreactor consists of valveless micropumps and a microchannel for mixing and reaction. Mixing speed was controlled by the pulsed mixing method with two micropumps and reaction temperature was controlled by micro thin-film heater fabricated on the backside of a microchannel chip. Then, gold naoparticle was synthesized using the fabricated microreactor. The coefficient of variation decreased with increasing the mixing speed and the percentage of spherically-shaped particle increased with increasing the reaction temperature. Finally, the coefficient of variation of 15 % and the percentage of spherically-shaped particle of 100 % for the mean diameter of 65 nm were achieved. © 2010 The Institute of Electrical Engineers of Japan.2010, IEEJ Transactions on Sensors and Micromachines, 130(7) (7), 5 - 299, Japanese[Refereed]Scientific journal
- 2010, 電気学会論文誌E（センサ・マイクロマシン部門誌）, 130-E(9) (9), 443 - 449, Japanese自己変位検出機能を有する面内2自由度静電櫛歯トランスデューサの等価回路[Refereed]Scientific journal
- 2010, 電気学会論文誌E（センサ・マイクロマシン部門誌）, 130-E(7) (7), 292 - 299, Japanese混合速度・温度制御可能な金ナノ粒子生成用マイクロリアクタ[Refereed]Scientific journal
- Tensile Testing of Single-Crystal Silicon Thin Films at 600 degrees C Using Infrared Radiation HeatingIn this paper, we report the development of a new tensile tester operable at 800 degrees C using an infrared radiation heating method to evaluate the mechanical properties of thin films at high temperature. The tester uses an electrostatic grip system for specimen chucking. We evaluated the grip force at high temperature and concluded that the electrostatic grip is effective up to 800 degrees C. Single-crystal silicon specimens of 3 mu M thickness and 4 gin width were tested at room temperature (RT) and 600 degrees C. At RT, the fracture strength and Young's modulus were 3.33 and 163.2 GPa, respectively. At 600 degrees C, they were 2.71 and 151.8 GPa, respectively. The stress and stage displacement curves at 600 degrees C with lower strain rate showed yield points and the fractured specimens exhibited slip lines.MYU, SCIENTIFIC PUBLISHING DIVISION, 2010, SENSORS AND MATERIALS, 22(1) (1), 1 - 11, English[Refereed]Scientific journal
- 2010, Experimental Mechanics, 50(4) (4), 509 - 516, EnglishTensile and Tensile-Mode Fatigue Testing of Microscale Specimens in Constant Humidity Environment[Refereed]Scientific journal
- We report a fabrication of doubly supported free-standing buckminster fullerene (C60) nanowires onto single crystal silicon microstructures in order to demonstrate an integration of carbon nanomaterials to surface-micromachined microelectromechanical devices. By irradiating vacuum-deposited C60 film with an electron beam, polymerized C 60 nanowires were patterned. Free-standing structures of the C 60 nanowires were obtained by sacrificial etching of underlying silicon structures using XeF2 gas. The supporting 5-μm thick silicon structure was released using vapor hydrofluoric acid. The C60 nanowire of 2-μm width, 25-μm length, and 40-nm thickness connected to a movable single crystal silicon structure was successfully fabricated. © 2009 Society of Photo-Optical Instrumentation Engineers.SPIE, 2009, Journal of Micro/Nanolithography, MEMS, and MOEMS, 8(1) (1), English[Refereed]Scientific journal
- A micro-machined piezoresistive type tactile sensor (5mm x 6mm), composed of two zigzag structures which act as spring, with 500 mu m cubic contact mesas at their tips, has been fabricated for detecting compliance of soft tissue. The concept of applying two springs, with considerably different stiffnesses, to soft tissue for compliance detection has been chosen to get output reading independent of the applied pushing distance between the sensor and the tissue. The testing process is done by three ways; by subjecting the sensor to 1-specimen chips with known stiffness, 2-silicone rubber, 3-chicken organs; namely heart, liver and leg.ELSEVIER SCIENCE BV, 2009, PROCEEDINGS OF THE EUROSENSORS XXIII CONFERENCE, 1(1) (1), 84 - +, English[Refereed]International conference proceedings
- 2009, The 8th International Workshop on High-Aspect-Ratio Micro-Structure Technology (HARMST2009), Saskatoon ,Canada, 153 - 154, EnglishMicroChannel Embedded in Glass-Frit Layer Bonding for Gas-Filled Sealed Cavity[Refereed]
- Direct stiffness calibration of microelectromechanical-system (MEMS) springs made of single-crystal silicon was performed using a previously developed mechanical force measurement tool. The spring devices used for calibration were fabricated from silicon-on-insulator wafers and contained one or four folded-beam springs. The spring constants were directly measured using an electromagnetic force-feedback balance with a force resolution of about 0.2 mu N. The average measured spring constant of a folded-beam spring with a designed constant of 0.7 N/m was 0.58 N/m. This successful calibration shows that this tool can be used to calibrate various kinds of MEMS flexible structures. (C) 2007 Elsevier B.V. All rights reserved.ELSEVIER SCIENCE SA, May 2008, SENSORS AND ACTUATORS A-PHYSICAL, 143(1) (1), 136 - 142, English[Refereed]Scientific journal
- This paper reports on the tensile testing of single crystal silicon (SCS), whose specimen surface was intentionally oxidized and the effect of the oxide thickness on the mechanical properties in order to investigate the fatigue fracture mechanism under cyclic loading. SCS specimens were fabricated from silicon-on-insulator (SOI) wafer with 5-μm -thick device layer and oxide layer were grown to the specimens using thermal dry oxidation at 1100℃. The specimen test part was 120 or 600 μm long and 4 μm wide. Quasi-static tensile testing of SCS specimen without oxide layer, with 50, 100, 200-nm-thick oxide was performed. As the results, the fracture origin location changed from the surface of the specimen of SCS without oxide to inside of silicon of oxidized specimen. This change may be caused by the oxidation stress near the interface and formation of oxide precipitation defects in silicon during oxidation.The Japan Society of Mechanical Engineers, 2008, The proceedings of the JSME annual meeting, 2008, 157 - 158, Japanese
- 2008, 電気学会論文誌E（センサ・マイクロマシン部門誌）, 128-E(4) (4), 151 - 160, Japanese超小型触覚ディスプレイ用垂直駆動SMA 薄膜アクチュエータの設計[Refereed]Scientific journal
- A detailed design procedure for a tactile sensor for compliance detection is developed. The sensor principle is based on the concept of applying two springs, with considerably different stiffnesses, to soft tissue for compliance detection. The spring stiffnesses are chosen to be associated with the soft tissue properties. The sensor design parameters are optimized to give high sensitivity and linearity of the sensor output with taking into account the effect of crosstalk between two springs due to the tissue deformation. A finite element model is developed to investigate the sensor performance with the designed parameters using two types of spring end, namely cubic and spherical in shape. The results show a significant stability of reading with the cubic end rather than the spherical one during pushing the sensor against a tissue. Finally, the same finite element model is used with changing the distance between the spring ends to show the crosstalk effect due to the tissue deformation. © 2008 The Institute of Electrical Engineers of Japan.2008, IEEJ Transactions on Sensors and Micromachines, 128(5) (5), 186 - 192, English[Refereed]Scientific journal
- We theoretically and experimentally evaluated the damping effect in a rotational resonator with a comb-drive actuator and sensor. The resonator was fabricated from an SOI wafer and has a fan-shaped mass. The underlying substrate was removed using back side deep reactive ion etching. One set of comb electrodes was attached to each side of the mass: one for electrostatic driving and the other for capacitive detection. In our theoretical analysis, the dynamics of the resonator were simplified so that they could be represented by a lumped system. In this lumped system, the damping coefficient was estimated by assuming the damping to be slide film damping and the air flow to be a Stokes flow. The phase shift due to the slide film damping of thick air layers was included in the lumped system. In the experimental evaluation, one side of the rotational combs was removed step-by-step and a half of the mass using a laser trimming tool so that the individual damping effects caused by the comb electrodes and mass could be determined quantitatively. We compared the experimental results with the results of the theoretical analysis and found that the difference in the damping coefficients between the experimental results and results of the theoretical analysis was less than 40%. © 2008 The Institute of Electrical Engineers of Japan.2008, IEEJ Transactions on Sensors and Micromachines, 128(5) (5), 203 - 208, English[Refereed]Scientific journal
- The novel sequential self-assembly process applying hybridization of DNA mediated micro/nano components was proposed and its validity was experimentally verified. In the proposed process, characteristic of DNA, such as hybridization specificity of complementary pairs of single-stranded DNA (ssDNA) into a double-stranded DNA (dsDNA), and its dependence on melting temperature Tm, which can be designed by the base-pair sequence and salt-concentration of surrounding media, was utilized to control the self-assembly sequence of a micro/nano components modified by ssDNA. Au nanoparticles with 15nm diameter were used as components and two pairs complementary DNA with different Tm were prepared. The aggregation of Au nano-particles modified by complementary ssDNA was confirmed at different temperatures with decreasing temperature under Tm. The reversibility of this process was also confirmed by increasing temperature.The Society of Powder Technology, Japan, 2008, Journal of the Research Association of Powder Technology, Japan, 45(3) (3), 156 - 161, Japanese
- A design of the micro-scaled tactile sensor which consists of two springs for Minimal Invasive Surgery was investigated. The sensing principle is based on the concept of applying two springs of considerably different stiffness to soft tissue for compliance detection, which reading is independent on the applied displacement between the sensor and tissue. Finite Element Method (FEM) is used to study the effect of tip shape (sphere, cubic) and the distance (0.5, 0.6, 0.7, 0.8mm) between the tips for the sensor with spring constants of 4500N/m and 110N/m under tissue Young's modulus of 0.3, 0.5, 1.0MPa. The results showed the cubic tip shape possesses independent reading on the pushing distance rather than the spherical one. The distance between the two springs of larger than 0.7mm is necessary to avoid the cross-talk effect between two spring behaviors.The Japan Society of Mechanical Engineers, 2007, The proceedings of the JSME annual meeting, 2007, 307 - 308, Japanese
- This paper reports on the development of a new tensile tester operable at 800℃ using infrared heating system for evaluating mechanical properties of thin films at high temperature. Single crystal silicon films of 3μm thick were tested at 600℃. At room temperature, the fracture strength and Young's modulus were 3.33GPa and 163.2GPa, respectively. At 600℃, they were 2.71GPa and 151.8GPa, respectively. When the strain rate was decreased, the stress and stage displacement curves had yield points and the fractured specimens exhibited the slip lines at 600℃.The Japan Society of Mechanical Engineers, 2007, The proceedings of the JSME annual meeting, 2007, 729 - 730, Japanese
- Versatile method of sub-micro particle pattern formation using self-assembly and two-step transferWe propose a method of sub-micro particle pattern formation with high productivity, flexibility and accuracy of pattern. The proposed process is composed of Template-Assisted Self-Assembly (TASA) for particle self-assembly and subsequent two-step transfer of the assembled particles. In the self-assembly process, the pattern of 70 % was successfully self-assembled. In the first transfer step, the transfer yield of 79 % was obtained by SAM (Self-Assembled Monolayer) coated carrier substrate. In the second transfer step, the transfer temperature of 115 degrees C provided the maximum transfer yield of 85 %. The overall process yield of 48 % was achieved by optimized process parameters and it was successfully demonstrated that the proposed method fabricates any sub-micro particle pattern.IEEE, 2007, PROCEEDINGS OF THE IEEE TWENTIETH ANNUAL INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS, VOLS 1 AND 2, 594 - 597, English[Refereed]International conference proceedings
- In this paper, a new sequential stacking self-assembly using interfacial tension of two different droplets of TEGDMA (Triethyleneglycol Dimethacrylate) and 42Sn-58Bi solder was proposed. TEGDMA with an additional thermal initiator is liquid at room temperature and hardens by heat. 42Sn-58Bi solder is solid at room temperature and melts at 138 °C. Since interfacial tension of TEGDMA and 42Sn-58Bi solder are selectively utilized by setting the process temperature at room temperature for TEGDMA and 150 °C for 42Sn-58Bi solder, the sequential self-assembly of different components can be realized. The feasibility of the proposed process and alignment accuracy were experimentally examined using 1 mm square silicon chips as test components. The first component assembly on a substrate was carried out at room temperature using TEGDMA as an adhesive agent, and the second component assembly on the assembled component was carried out at 150 °C using 42Sn-58Bi solder as an adhesive agent. Both self-assembly processes were carried out in EG (Ethylene Glycol) solvent with an additional sulfuric acid. It was confirmed that the first and second self-assembly was successfully done at room temperature and at 150 °C, and alignment accuracy of first and second self-assembly were 33 μm and a few μm, respectively.The Institute of Electrical Engineers of Japan, 2007, 電気学会論文誌E（センサ・マイクロマシン部門誌）, 127-E(4) (4), 214 - 220, Japanese[Refereed]Scientific journal
- The spring constant of a folded beam structure was directly measured for the calibration of the force-displacement transferring spring in the MEMS tensile testing device for nanoscale materials. The force that can be applied to the spring is up to 100μN, so Thin film tensile tester using electromagnetic balance was adopted. First, we improved the force-measurement resolution of the tensile tester through the review of the stability of the control system, the test environment, the noise in the control current, and the set-up of the testing system. Second, we measured the spring constant with a device containing four folded beams. The spring beams were 2μm width, 5μm thick, and 216μm and 285μm long, whose spring constant are designed to be 0.3N/m and 0.7N/m respectively. The measured values were 0.18N/m and 0.57N/m, which were distinct from the designed values, but close to the modified analytical value in which actual cross section areas were considered.The Japan Society of Mechanical Engineers, 2006, The proceedings of the JSME annual meeting, 2006, 299 - 300, Japanese
- IOP Publishing, Jun. 2005, Journal of Micromechanics and Microengineering, 15(6) (6), 1236 - 1241, English[Refereed]Scientific journal
- IOP Publishing, Nov. 2002, Journal of Micromechanics and Microengineering, 12(6) (6), 911 - 916, English[Refereed]Scientific journal
- Springer Science and Business Media LLC, Nov. 2002, Microsystem Technologies, 9(1-2) (1-2), 11 - 16, English[Refereed]Scientific journal
- A new technique to control selectivity of mask materials during XeF2 etching was proposed. By exposing Si sample with SiO2 and Si3N4 as mask materials to UV light of 981 mW/cm2 during XeF2 etching, the etching rate ratios of Si/SiO2 and Si/Si3N4 were dramatically decreased from 11446 to 906.1 and from 488.2 to 29.3, respectively. This new technique allows us to remove the mask material selectively and change the mask pattern by UV light exposure during in-situ etching process without additional photolithography step and opens a new silicon micromachining process for 3-dimensional fabrication. The multi-step Si structure was successfully realized by this technique. Keywords: XeF2, 3-dimentuional microstructure, ultra violet light, selectivity. © 2001, The Institute of Electrical Engineers of Japan. All rights reserved.2001, IEEJ Transactions on Sensors and Micromachines, 121(12) (12), 647 - 651, English[Refereed]Scientific journal
- Oct. 2020, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 37, 5p, Japaneseマイクロ振動子のたわみ状態制御による振動型光センサの高感度化—Study on sensitivity improvement of microresonator-based optical sensor by deflection control
- Oct. 2020, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 37, 5p, Japanese高温パンチクリープ成形技術を用いた3軸力センサの開発および被覆樹脂の粘弾性特性を考慮したセンサ性能評価—Development of three-axis force sensor by 3D microstructuring using high temperature punch creep forming and sensor performance evaluation considering resin viscoelasticity
- Oct. 2020, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 37, 6p, Japanese金ナノ構造を用いた波長依存性を有するSOI型近赤外ボロメータ素子—Study on wavelength-dependent SOI-type near-infrared bolometer element using gold nanostructure
- Oct. 2020, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 37, 6p, Japanese金ナノ構造光吸収体集積静電型マイクロ振動子デバイスによる近赤外光強度センサ—Near-infrared light intensity sensing by electrostatic microresonator transducer integrated with gold nanostructure optical absorber
- Oct. 2020, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 37, 5p, Japanese近赤外吸収体を有する静電型マイクロ振動子デバイスを用いた水の分光測定—Spectroscopic measurement of water using electrostatic transducer with Near-infrared absorber
- Oct. 2020, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 37, 6p, Japanese金ナノ粒子二量体を用いたナノギャップ電極の作製とその電気的・光学的評価—Fabrication of nanogap electrode based on gold nanoparticle dimer and its electrical and optical evaluation
- Oct. 2020, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 37, 6p, Japanese光センシングマイクロ共振デバイスの梁長さおよび振幅が計測分解能に与える影響—Effects of beam length and amplitude on measurement resolution in optical sensing using microresonator
- Nov. 2019, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 36, 6p, Japanese光励起ナノギャップ電極を用いたDNAオリゴマーの光トラップおよび1分子検出—Optical trapping and single-molecule detection of DNA oligomer using optically-excited nanogap electrodes
- Nov. 2019, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 36, 4p, Japanese架橋成長Siナノワイヤの熱電特性評価に関する研究—Characterization of thermoelectric properties of bridged-grown Si nanowire
- Nov. 2019, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 36, 4p, Japaneseシリコンマイクロ振動子光センサにおける共振周波数特性の形状依存性—Pattern dependency of resonant frequency response of silicon microresonator for optical sensing
- Nov. 2019, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 36, 4p, Japanese金ナノグレーティング構造の光吸収ピーク波長制御による高感度レーザ波長計測マイクロ振動子デバイス—Highly sensitive laser wavelength measurement using microresonator controlling absorption peak of gold nanograting
- Nov. 2019, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 36, 4p, JapaneseコアシェルSiCナノワイヤの電気伝導性に及ぼすシェル表面電位の影響解明—Effect of shell surface potential to electrical properties of core-shell SiC nanowire
- 2018, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 35, 6p, JapaneseSi薄膜被覆金ナノグレーティング構造の近赤外域光吸収スペクトル偏光依存性—Polarization dependence of near-infrared absorption spectrum of Si-deposited gold nano-grating structures
- 2018, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 35, 5p, JapaneseVLS成長SiNW単体に対する熱電変換特性評価—Characterization of thermoelectric properties for VLS-growth SiNWs
- Institute of Electrical Engineers of Japan, 31 Oct. 2017, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 34, 6p, JapaneseNear-infrared optical property of Si-deposited gold nanowire grating structures
- Institute of Electrical Engineers of Japan, 31 Oct. 2017, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 34, 1 - 5, JapaneseDevelopment of tiny MEMS tactile sensor using high temperature creep forming technique
- The Institute of Electrical Engineers of Japan, Jun. 2017, 電気学会誌, 137(6) (6), 354 - 357, Japanese
1．はじめに
化学物質成分分析および生命科学分野において低濃度の物質を高感度に検出・同定する技術が広く期待されている。例えば，水質検査における環境ホルモン等有害物質の検出や農作物の残留農薬検出，空港等でのセキュリティのための危険物質検出等が挙げられる。生命科学分野では，
[Refereed][Invited]Introduction scientific journal - 電気学会, 19 Dec. 2016, 電気学会研究会資料. PHS, 2016(58) (58), 43 - 46, JapaneseSurface-Enhanced Raman Spectroscopy Detection of Adenine Molecule using single Gold Nanoparticle dimer
- 電気学会, 19 Dec. 2016, 電気学会研究会資料. MSS, 2016(27) (27), 1 - 3, JapaneseOptical Property of Si thin film deposited gold nanowire array
- Institute of Electrical Engineers of Japan, 02 Oct. 2016, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 33, 1 - 4, JapaneseStudy on High Temperature Creep Deformation of Si Thin Film by Backward Analysis Method for Development of Tactile Sensors
- Institute of Electrical Engineers of Japan, 02 Oct. 2016, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 33, 1 - 4, JapaneseEvaluation of Piezoresistivity of VLS-Grown Core/Shell-SiC Nanowires Using Electrostatically Actuated Nanotensile Testing Device
- Institute of Electrical Engineers of Japan, 02 Oct. 2016, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 33, 1 - 6, JapaneseHighly-Sensitive and Rapid Detection of DNA bases using Surface-Enhanced Raman Spectroscopy with Gold Nanoparticle Dimer Array
- Institute of Electrical Engineers of Japan, 28 Oct. 2015, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 32, 4p, JapaneseCrystal Orientation Dependency of Strain-Induced Electrical Properties for VLS-Grown Single Crystal Silicon Nanowires
- Institute of Electrical Engineers of Japan, 28 Oct. 2015, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 32, 1 - 4, JapaneseSurface enhanced Raman spectroscopy of nucleobases using gold nanoparticle dimer array
- Institute of Electrical Engineers of Japan, 28 Oct. 2015, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 32, 1 - 5, JapaneseCharacterization method of Raman enhancement for surface enhanced Raman spectroscopy using gold nanoparticle dimer array
- Institute of Electrical Engineers of Japan, 28 Oct. 2015, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 32, 1 - 5, JapaneseCharacterization of surface enhanced Raman spectroscopy with straight arrangement of gold nanoparticles
- The Japan Society of Mechanical Engineers, 04 Oct. 2015, Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics, 2015(14) (14), 184 - 184, EnglishOS12-2 Evaluation of Piezoresistivity for VLS-Grown Silicon Nanowires Under Enormous Elastic Strain(Mechanical properties of nano- and micro-materials-1,OS12 Mechanical properties of nano- and micro-materials,MICRO AND NANO MECHANICS)
- Oct. 2014, 第31回「センサ・マイクロマシンと応用システム」シンポジウム, 20pm1-B1, Japanese金ナノ粒子二量体の規則的配列構造による高感度表面増強ラマン分光
- J2240304 Evaluation of Shear Piezoresistance Coefficient of Silicon Nanowire by Asymmetrical Four Point Bending TestThis research evaluated the shear piezoresistance property of p-type single crystal silicon nanowire (SiNW) by the asymmetrical four-point bending (AFPB) testing proposed by the authors. We fabricated the p-type SiNW on the AFPB specimen with "V"-shaped notches (V-notches) made of single crystal silicon. Bending the specimen by the asymmetrical four point-supports, simple shear stress can be produced at the center of the specimen. Consequently, we have succeeded in evaluating the shear piezoresistance coefficient of SiNW directly, which was found to be π_<44>=203.28×10^<-11> Pa^<-1> at an impurity concentration of 4×10^<18> cm^<-3>. This value is 2.1 times larger than that of p-type piezoresistors used in conventional piezoresistance sensors on a micrometer scale. The proposed evaluation technique and obtained result will be effective for design application of high-sensitivity mechanical sensors integrating SiNW piezoresistance elements.The Japan Society of Mechanical Engineers, 07 Sep. 2014, Mechanical Engineering Congress, Japan, 2014, "J2240304 - 1"-"J2240304-5", Japanese
- May 2014, 平成26年度電気学会センサ・マイクロマシン部門総合研究会(マイクロマシン・センサシステム研究会), 電気学会, MSS-14-011, Japanese一方向に配列した金ナノ粒子二量体構造の表面増強ラマン分光特性評価
- 日本板硝子材料工学助成会, 2014, 財団法人日本板硝子材料工学助成会成果報告書 Nippon Sheet Glass Foundation for Materials Science and Engineering report, (35) (35), 169 - 173, JapaneseMicro Energy Harvesting Device Using Ferroelectrics as an Electret Material
- Nov. 2013, 第30回「センサ・マイクロマシンと応用システム」シンポジウム, 電気学会, 6PM3-PSS-058, Japanese静電容量型SOI3軸加速度センサの角速度横感度
- Sep. 2013, 日本機械学会2013年度年次大会, 日本機械学会, J211013, Japanese(100)及び(110)単結晶シリコンにおける引張強度の結晶方位依存性
- Sep. 2013, 日本機械学会2013年度年次大会, 日本機械学会, J211017, Japanese多段ICP-RIEプロセスを用いた架橋構造Siナノワイヤの加工
- Sep. 2013, 日本機械学会2013年度年次大会, 日本機械学会, J211024, Japaneseビオチン修飾1本鎖DNAを用いた単層カーボンナノチューブのギャップ電極への孤立アセンブル
- Aug. 2013, Dynamics and Design Conference 2013(D&D2013), 日本機械学会, 講演番号549, Japanese3軸加速度センサのマトリックス感度校正における取付角度誤差の影響評価
- Apr. 2013, The 10th International Workshop on High Aspect Ratio Micro and Nano System Technology, 192 - 193, EnglishNovel process optimization approach for DMD-based grayscale 3D microstructuring photolithography
- Mar. 2013, 平成25年電気学会全国大会, 191 - 192, Japanese節付きBoschプロセスによるシリコン3層構造の作製
- Mar. 2013, 平成25年電気学会全国大会, 193 - 194, JapaneseグレースケールDMD露光用3次元微細加工プロセスシミュレータ
- Institute of Electrical Engineers of Japan, Jan. 2013, 「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 30, 6p, JapaneseNew fabrication method and evaluation of alkali-metal vapor cells for atomic magnetometer
- Jan. 2013, 日本実験力学会講演論文集, (13) (13), 129 - 131, Japanese時間分解顕微ラマン分光のためのプルイン型MEMS光チョッパの動作特性 (2013年度年次講演会)[Refereed]
- Jan. 2013, 電子情報通信学会ソサイエティ大会講演論文集, 2013, S - 28, Japanese
- The rotational motion effect on the sensitivity matrix of a MEMS three-axis accelerometer was evaluated to realize the concurrent calibration of multiple MEMS accelerometers using a multi-axis shaker. The stage position dependency on the sensitivity matrix of a single-mass capacitive SOI three-axis accelerometer was measured. We found that the rotational motions generated by the resonance of the shaker causes an acceleration error on the accelerometer and can be compensated by measuring it using gyroscopes. © 2013 IEEE.2013, Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), 645 - 648, English[Refereed]
- Oct. 2012, 第29回「センサ・マイクロマシンと応用システム」シンポジウム, 371 - 374, Japanese粗視化分子動力学シミュレーションによる架橋度制御ネガレジストの分子透過係数解析
- Oct. 2012, 第4回「マイクロ・ナノ工学シンポジウム」, OS7-3-5, Japanese単層カーボンナノチューブの MEMS 引張試験における顕微ラマン分光を用いたひずみ測定
- 702 Evaluation of Effects of Rotational Motion on Vibration Table in Sensitivity Matrix Calibration of 3-axis AccelerometerThe calibration method based on a vector space theory has been proposed for multi-axis accelerometers. In this method, acceleration generated from a 3-DOF vibration table and the output signal from calibration target accelerometers are treated as vector quantities and a calibration result is described as a matrix. This method has many advantages of short measurement time and cross sensitivity evaluation. In order to realize more efficient measurement, a simultaneous calibration technique is required. However, it is supposed that uncontrolled rotational motion of a 3-DOF vibration table generates position dependency on some of the elements of sensitivity matrix. This paper reports the effect of rotational motion on the vibration table in the sensitivity matrix calibration of an SOI capacitive 3-axis accelerometer. In order to clarify the rotation effect on sensitivity, we made a 6-DOF reference sensor in combination of 3 single axis accelerometers and 3 single axis gyros As a result, certain elements of the cross sensitivity show the position dependency at a 150Hz excitation, which could be near the resonant frequency of rotation. This result is explicable by approximate expression of sensitivity calculation.The Japan Society of Mechanical Engineers, 18 Sep. 2012, Dynamics & Design Conference, 2012, "702 - 1"-"702-10", Japanese
- Jul. 2012, The 6th IEEE Asia-Pacific Conference on Transducers and Micro-Nano Technology (APCOT2012), ac12000168, EnglishInvestigation of Nonlinear Decrease of Autofluorescence in Negative Thick-Film Resist
- 11 Jun. 2012, 電気学会マイクロマシン・センサシステム研究会資料, MSS-12(1-22) (1-22), 29 - 32, JapaneseFabrication of nanogap electrodes by gold nanorod growth on substrate
- 11 Jun. 2012, 電気学会マイクロマシン・センサシステム研究会資料, MSS-12(1-22) (1-22), 33 - 38, JapaneseAnalysis of aggregation reaction for silver nanoparticle dimers toward highly sensitive SERS
- Apr. 2012, 2012 MRS Spring Meeting, San Francisco, B7.5, EnglishVibration analysis of coupled vertical resonators for acceleration sensitivity reduction of out-of-plane vibratory gyroscopes
- Mar. 2012, The 7th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 411 - 412, EnglishTemperature dependency of DNA origami self-assembly rate
- Mar. 2012, The 7th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 652 - 653, EnglishFabrication of nanogap electrodes by gold nanorod growth on substrate
- Mar. 2012, The 7th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 999 - 1000, EnglishModeling and elastic property simulation of epoxy-based negative photoresist using coarse-grained molecular dynamics
- Mar. 2012, The 7th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 335 - 336, EnglishTensile testing of SWCNT using thermal actuator clamped with electrolessly deposited gold layer
- Mar. 2012, 応用物理学会 第59回 応用物理学関係連合講演会, 0, Japanese自己変位検出型静電櫛歯等価回路モデルを用いたMEMS振動ジャイロ解析
- The article presents a new equivalent circuit model of electrostatic comb transducers for an integration of MEMS into LSI. The model detects the displacement using a dummy spring to express the current induced by the movement, and the model parameters can be derived from only its dimensions not from external parameters, such as acting force and applied voltage. In addition, being composed from basic circuit components, the model is easily utilized in conventional circuit simulation software. The in-plane two-degree-of-freedom comb model was applied to a simple SOI coupled resonator and the measured and simulated electrical and mechanical properties showed good agreement with each other. The model was also applied to a decoupled two-axis resonator for a vibrating gyroscope made on silicon-on-glass substrate. Frequency tuning and oscillating circuit with constant amplitude control have been tested and the tuning results and transient responses showed good agreement as well. © 2012 IFIP International Federation for Information Processing.2012, IFIP Advances in Information and Communication Technology, 379, 94 - 109, English
- A unique simulation method of epoxy-based chemically-amplified resist by coarse-grained molecular dynamics was proposed. The mechanical properties of an epoxy-based chemically-amplified resists with various cross-linking ratios were simulated using a newly developed coarse-grained molecular dynamics simulation that employs a bead-spring model. Models with the different cross-linking ratios were created in the molecular dynamics calculation step and uniaxial elongation simulations were performed. The results reveal that the simulated elastic modulus of the resist modeled by the bead-spring model with an extended angle bending potential depends on the cross-linking ratio its dependency exhibits good agreement with that determined by nanoindentation tests. © 2012 Materials Research Society.2012, Materials Research Society Symposium Proceedings, 1415, 59 - 64, English[Refereed]
- Equivalent circuit analysis for electrostatic nonlinear resonators was conducted for evaluating the efficiency of vibrating energy harvesting devices. Non-linear models for a parallel plate capacitor and doubly clamped beam as well as a non-linear response analysis method on a spice tool have been developed. Measurements from fabricated resonators were in good agreement with output from simulation models. These models were applied for evaluating the efficiency of nonlinear resonators as energy harvesters but no significant improvement compared to linear resonators was obtained. © 2012 IEEE.2012, Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), 1213 - 1216, English[Refereed]
- Biocompatible permeable membranes integrated with a microfluidic system, which allow the diffusion of biological molecules with certain molecular weight, are desirable in biomedical applications. This paper reports on a molecular level study of the molecules permeability of epoxy-based chemically-amplified photoresists in MEMS by employing a coarse-grained molecular dynamics simulation. For analyzing diffusion coefficient of molecular in photoresists, Kremer-Grest model (bead-spring model) with an extended angle bending potential was employed. The simulation results show that, with increasing the cross-linked ratio of photoresists, the diffusion coefficient of small molecules in photoresist have larger diffusion coefficient, and which suggests photoresist membrane can be used as permeable membranes with controllable permeability by varying photolithography parameters. (C) 2012 Elsevier Ltd.... Selection and/or peer-review under responsibility of the Symposium Cracoviense Sp. z.o.o.ELSEVIER SCIENCE BV, 2012, 26TH EUROPEAN CONFERENCE ON SOLID-STATE TRANSDUCERS, EUROSENSOR 2012, 47, 402 - 405, English[Refereed]
- In this study, we proposed a novel mixing method using alternate pulsed flows from three inlet channels using three piezoelectric valveless micropumps. Two solutions are assigned into one micropump and the other two micropumps, respectively. The fabricated microfluidic device consists of a cross-shaped mixing channel with three inlet microchannels and three valveless micropumps. According to the experimental results, it was confirmed that the pulsed mixing using three inlet microchannels increased mixing speed with increasing the switching frequency of the micropump driving up to 200 Hz. The proposed method solved the problem of a bias of concentration ratio near the sidewalls which has happened in the previous pulsed mixing method using T- or Y-shaped microchannel with two inlet microchannels. Furthermore, by controlling a solution flow at the confluent area utilizing a reverse flow of the micropump, the mixing speed dramatically increased and the mixing time of 3.6 ms for 90 % mixing ratio was achieved at the micropumps switching of 400 Hz.AMER SOC MECHANICAL ENGINEERS, 2012, FLUID MEASUREMENTS AND INSTRUMENTATION CAVITATION AND MULTIPHASE FLOW ADVANCES IN FLUIDS ENGINEERING EDUCATION MICROFLUIDICS, VOL 2, 2, 365 - 369, English[Refereed]
- Dec. 2011, Proceedings of International Workshop on Micro/Nano-Engineering, 88Coarse-Grained Molecular Dynamics Simulation Approach for Mechanical Property of Epoxy-Based Chemically-Amplified Resist
- 21 Nov. 2011, 電気学会電子回路研究会資料, ECT-11(102-112) (102-112), 7 - 11, Japanese微細加工技術を応用したチップスケール原子磁気センサ用気密封止技術
- Sep. 2011, 第28回「センサ・マイクロマシンと応用システム」シンポジウム, 107 - 110, Japanese誘電泳動によりアセンブルしたSWCNTの無電解Auめっきによる機械的・電気的クランピング
- Sep. 2011, 第28回「センサ・マイクロマシンと応用システム」シンポジウム, 334 - 339, JapaneseMEMS厚膜ネガレジストの粗視化分子動力学モデル
- Sep. 2011, 第28回「センサ・マイクロマシンと応用システム」シンポジウム, 149 - 153, Japaneseナノトレンチテンプレートを用いたナノギャップ制御可能なナノ粒子セルフアセンブリ
- Sep. 2011, 日本化学会第63回コロイドおよび界面化学討論会, 289, Japaneseナノギャップ電極の作製に向けた金ナノロッドの基板上成長
- Sep. 2011, 日本機械学会2011年度年次大会, 2011, J161021, Japaneseエポキシ系ネガレジスト機械的特性の架橋度依存性
- Jul. 2011, 関西ワークショップ2011, エレクトロニクス実装学会,, No.11, Japaneseガラスフリットリフローによる犠牲マイクロ流路気密封止技術の確立と小型原子磁気センサ実装への応用
- 01 Jul. 2011, 電気学会マイクロマシン・センサシステム研究会資料, MSS-11(1-7.9-12.14-21) (1-7.9-12.14-21), 83 - 86, JapaneseHigh-precision and High-yield Self-Assembly of Gold Nanoparticles using Nano-scale Trenches
- 01 Jul. 2011, 電気学会マイクロマシン・センサシステム研究会資料, MSS-11(1-7.9-12.14-21) (1-7.9-12.14-21), 73 - 78, JapaneseSynthesis of Gold Nanoparticle using High-speed Pulsed Mixing Microfluidic Device
- 01 Jul. 2011, 電気学会マイクロマシン・センサシステム研究会資料, MSS-11(1-7.9-12.14-21) (1-7.9-12.14-21), 31 - 36, JapaneseEquivalent Circuit Analysis of Nonlinearity Response in Electrostatic Comb Resonator
- Jun. 2011, 平成23年度電気学会マイクロマシン・センサシステム部門総合研究会, 31 - 36, Japanese電気等価回路を用いた静電櫛歯型MEMS振動子の非線形応答解析
- Jun. 2011, The 9th International Workshop on High-Aspect-Ratio Micro-Structure Technology (HARMST2011),, pp. 62-63, 62 - 63, EnglishMechanical characterization of negative photoresist by nano-indentation for nano-filtration membrane[Refereed]
- Mar. 2011, 平成23年電気学会全国大会, 186 - 187, Japanese高速脈動混合マイクロ流体デバイスを用いた均一粒子径金ナノ粒子の合成
- Feb. 2011, The 6th IEEE International Conference on Nano/Micro Engineered and Molecular Systems,, pp. 1297-1300, 1297 - 1300, EnglishModal harmonic simulation of decoupled resonators for developing MEMS tuning fork gyroscope with low acceleration sensitivity[Refereed]
- The paper presents a new equivalent circuit model of electrostatic comb transducers for large-scale integration of MEMS into LSI. The model detects the displacement using a dummy spring to express the current induced by the movement, and the model parameters can be derived from only its dimensions not from external parameters (acting force, applied voltage). In addition, the model is composed from basic circuit components. Therefore it is easily utilized in conventional circuit simulation software. In-plane two-degree-of-freedom comb model was applied to basic SOI resonator and the measured and simulated electrical and mechanical properties showed good agreement in each other. A simple oscillating circuit with constant amplitude control has been tested and the transient responses showed good agreement as well. © 2011 IEEE.2011, 2011 IEEE/IFIP 19th International Conference on VLSI and System-on-Chip, VLSI-SoC 2011, 208 - 213, English[Refereed]
- We report for the first time on a simple fabrication via UV photolithography for a free-standing filtration membrane made of epoxy-based photoresist and its integration on a multilevel microfluidic device. The fabrication process involves three-dimensional thick-photoresist microstructuring combined with standard negative photoresist processing. In this paper, a primary feature of membrane permeability dependence on fabrication process parameters was characterized by employing a cross-linking reaction model. The experiments using a multilevel microfluidic device demonstrated the proposed fabrication is capable of fabricating nano-filtration membrane while maintaining a sufficient mechanical strength for applications in polymer-based microfluidic devices. © 2011 IEEE.2011, NEMS 2011 - 6th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 184 - 187, English[Refereed]
- This paper reports transient equivalent circuit analysis for self-induced oscillation of micromechanical resonator using a novel component model of an electrostatic comb transducer. The model with built-in displacement detection can analyze dc operating points which depends on both on electrical and mechanical biases. By using the proposed model, we analyzed the bias voltage dependency of oscillation risetime and amplitude. From comparing the analysis and measurement of start-up transient response of an SOG (silicon-on-glass) resonator, we showed the proposed comb model facilitate designing and estimate oscillator performance. © 2011 IEEE.2011, NEMS 2011 - 6th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 1241 - 1245, English[Refereed]
- This paper reports on a novel and simple packaging technique to enhance the atmosphere controllability of the microfabricated alkali vapor cell used for CSAMs (Chip Scale Atomic Magnetometers), in which sacrificial microchannels at the bonded interface are utilized as gas feedthrough for evacuation and filling, subsequently sealed by glass-frit reflow. By applying the proposed method, a 10 mm(3) potassium vapor cell with 0.1 MPa helium buffer gas was fabricated. Sealing of the microchannels by glass-frit reflow were successfully demonstrated adopting the optimized parameters as 460-480 degrees C at bonding pressure of more than 250 kPa. The leak rate of less than 3.1x10(-14) Pa.m(3)/s, which is required sealing quality for CSAM, was verified through a high resolution helium leak test.IEEE, 2011, 2011 IEEE 24TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS), 368 - 371, English[Refereed]
- This paper reports a method for analyzing local stress in resonating single-crystal silicon (SCS) microstructures of various crystal orientations using micro Raman spectroscopy. The notched support beams of fan-shaped in-plane resonators were used as specimens. The specimens have five different crystallographic orientations. The spectra at notch tips were calculated using the Raman spectrum of Si without stress and the stress distribution analyzed by finite element method (FEM). The measured spectra of all (100) and most of (110) specimens showed good agreement with the analyzed ones, which indicates the validity of this method.IEEE, 2011, 2011 IEEE 24TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS), 449 - 452, English[Refereed]
- We report on a simple UV photolithography based fabrication for an epoxy-based filtration membrane and its primary features such as the permeability and the elastic modulus toward a design of polymer-based microfluidic systems. The elastic modulus of filtration membrane was measured by an indentation test, and then which was evaluated by a cross-linked ratio of epoxy group to clarify the dependence on the process parameters. It was revealed for the first time that the elastic modulus for filtration membrane varied from 3.8 GPa to 4.9 GPa according to the cross-linked ratio of 0.5 to 0.75. © 2011 IEEE.2011, 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference, TRANSDUCERS'11, 2706 - 2709, English[Refereed]
- In this study, we proposed a novel mixing method using alternate pulsed flows from three inlet channels with piezoelectric valveless micropumps. It was experimentally and analytically confirmed that the proposed pulsed mixing of two solutions increased mixing speed with increasing the switching frequency of up to 400 Hz. The mixing time of 3.6 ms for 90 % mixing ratio of two solutions was achieved experimentally at the switching frequency of 400 Hz. The further increase in the mixing speed up to 800 Hz was analytically confirmed. As its application, gold nanoparticle was synthesized using the proposed method and the uniformity of particle sizes increased with the mixing speed. © 2011 IEEE.2011, 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference, TRANSDUCERS'11, 1773 - 1776, English[Refereed]
- This paper presents an analysis of acceleration output (sensitivity) in MEMS tuning fork gyroscopes (TFG) using simplified coupled resonators. We found that in TFG, applied acceleration in in-phase is transduced into excitation of anti-phase mode by unbalanced phase responses of the resonators. We proposed two mechanism and reduction methods (1) coupling of the in- and anti-phase modes (frequency decoupling) and (2) energy dissipation from the anchors with different vibration systems and supporting structures. They were analyzed using FEM simulations and verified by experiments. Results showed that acceleration output decreased by one-tenth for decoupling ratio from 0.09 to 0.29. © 2011 IEEE.2011, 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference, TRANSDUCERS'11, 2006 - 2009, English[Refereed]
- This paper reports high-yield self-assembly process for gold nanoparticle with a diameter of 60 nm, which can precisely control an interparticle nanogap ranging from 0 to 60 nm, using a template-assisted self-assembly with a pair of circular nanotrenches. A center-to-center distance of nanotrenches was changed in order to control an interparticle nanopgap. We found that an assembly yield strongly depends on a particle-particle interaction and achieved nanogap-controlled particle arrangement with high yield by controlling the particle-particle interaction with an addition of an electrolyte. This technique would enable us to control plasmonic resonance property of a nanoparticles pair for many emerging applications. © 2011 IEEE.2011, 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference, TRANSDUCERS'11, 2570 - 2573, English[Refereed]
- In this study, we proposed a novel mixing method using alternate pulsed flows from three inlet channel using piezoelectric valveless micropumps. Two solutions are assigned into one micropump and the other two micropumps, respectively. The fabricated microfluidic device consists of a cross-shaped mixing channel with three inlet microchannels and three valveless micropumps. According to the experimental results, it was confirmed that the pulsed mixing using three inlet microchannels increased mixing speed with increasing the switching frequency of the micropump driving up to 200 Hz. The proposed method solved the problem of a bias of concentration ratio near the sidewalls which has happened in the previous pulsed mixing method using T- or Y-shaped microchannel with two inlet microchannels. Furthermore, by controlling a streamline of solution flow at the confluent area utilizing a reverse flow, the mixing speed dramatically increased and the mixing time of 3.6 ms for 90 % mixing ratio was achieved at the micropumps switching of 400 Hz. © 2011 IEEE.2011, NEMS 2011 - 6th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 75 - 78, English[Refereed]
- This paper presents analysis of the acceleration sensitivity (output) in decoupled resonators and a proposal of a new method to suppress acceleration output by controlling frequency decoupling of coupled resonators for developing MEMS tuning fork gyroscope (TFG) with low acceleration sensitivity. We identified that unbalancing of two sense resonators in TFG caused by fabrication error converts external acceleration into anti-phase vibration. This anti-phase vibration appeared as the rate output, which is called acceleration output in gyroscope. In order to reduce the acceleration output, decoupling between in-phase and anti-phase modal frequency is crucial, since coupled resonators may cause large anti-phase vibration from acceleration. To confirm the acceleration output model, we designed two types of decoupling methods of artificially unbalanced resonators. Through modal harmonic analysis, the anti-phase vibration reduced by one-tenth by increasing decoupling ratio from 0.09 to 0.29, irrespective to resonator designs. © 2011 IEEE.2011, NEMS 2011 - 6th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 1250 - 1253, English[Refereed]
- This paper presents an analysis of the acceleration output (sensitivity) in frequency decoupled MEMS tuning fork gyroscopes (TFG). We found that in-phase acceleration input is transduced into excitation of anti-phase mode, which results into acceleration output. Therefore, frequency decoupling (decoupling ratio, DR) of in-and anti-phase modes of sense resonators is key factor to suppress acceleration output in TFG, which was verified in a fully operating tuning fork gyroscope. The FEA simulation results showed that as DR increases, the acceleration output decreased from 73.56deg/s/g to 23.42deg/s/g. (C) 2011 Published by Elsevier Ltd.ELSEVIER SCIENCE BV, 2011, EUROSENSORS XXV, 25, 623 - 626, English
- 2011, NEMS 2011 - 6th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 197 - 200, English[Refereed]
- Nov. 2010, Core-to-Core 2010 World Network Seminar on Advanced Particle Science and Technology, 99, EnglishNanogap-controllable Arrangement of Gold Nanoparticles Using Template-Assisted Self-Assembly
- MNM-3A-4 Crystallographic anisotropy analysis in fracture of micro-sized (110) single crystal silicon using Weibull statisticsUniaxial tensile testing for single crystal silicon (SCS) films was conducted to investigate the fracture mechanism of silicon. The loading axis of the SCS specimens had three main crystallographic orientations, that is <100>, <110>, and <111>, fabricated from one (110) silicon-on-insulator wafer. The dimensions of specimen test part were 10 μm wide, 5 μm thick, and 120 μm long having 1 μm-depth notch at the center. The measured average fracture force of <100>, <110>, and <111> specimens was 44.2, 53.5, and 45.8 mN, respectively. The difference in fracture force between <110> and <111> specimens was well elucidated with the normal stress for (111) cleavage plane using Weibull statistics considering the stress distribution on notch surface and existence of multiple cleavage planes in SCS.The Japan Society of Mechanical Engineers, 12 Oct. 2010, 日本機械学会マイクロ・ナノ工学シンポジウム講演論文集, 2nd(2) (2), 149 - 150, Japanese
- MNM-P11-3 Performance analysis of vibrating gyroscope using equivalent circuit of electrostatic comb transducer with built-in displacement detectionThis paper reports transient analysis in self-induced oscillation of vibrating gyroscope by using the novel electrical equivalent circuit of electrostatic comb transducer. The equivalent circuit with built-in displacement detection can analyze dc operating points which depends on external parameters like springs, bias voltage and force. By using the proposed equivalent circuit, we estimated the bias voltage dependency of oscillation risetime and voltage amplitude. By comparing the analysis and measurement of start-up response of SOG (silicon-on-glass) gyroscope, we showed the proposed equivalent circuit facilitate designing and estimate gyroscope performance.The Japan Society of Mechanical Engineers, 12 Oct. 2010, マイクロ・ナノ工学シンポジウム, 2010(2) (2), 141 - 142, Japanese
- Oct. 2010, 第27回「センサ・マイクロマシンと応用システム」シンポジウム, 656 - 661, Japaneseチップスケール原子磁気センサのためのガラスフリットリフローによる犠牲マイクロ流路気密封止技術
- In this paper, we report on uniaxial tensile tests for single crystal silicon (SCS) specimens having three different crystallographic orientations such as <100>, <110>, and <111> in loading axes, to evaluate the crystal anisotropy on the fracture behavior. The specimens were fabricated on the same (110) silicon on insulator(SOI) wafer. The test parts were 10μm wide, 5μm thick, and 120μm long and they have 1μm-depth notch at the center. The fracture force of <100>, <110>, and <111> specimens were 45.1, 55.9, and 45.5 mN, respectively. The fracture surface of <111> and <110> specimens were mostly in (111) plane.The Japan Society of Mechanical Engineers, 04 Sep. 2010, The proceedings of the JSME annual meeting, 2010(Vol.8) (Vol.8), 243 - 244, Japanese
- This paper describes a method for analyzing local stress in resonating single-crystal silicon (SCS) microstructures using micro Raman spectroscopy. The support beams of fan-shaped resonators with five different crystallographic orientations are used as specimens. The beam dimensions are same, which are 30μm long, 10μm wide and 5μm thick and it has a 4-μm-deep notch in its center. Raman spectra at the notch tips were measured during resonant vibrations. The observed spectra are broadened by stress oscillation. These spectra broadening are theoretically analyzed by time integration of no-stress spectra with stress distribution analysis using finite element method. The analyzed and measured spectra of the (100) Si specimens showed good agreement, which indicates the validity of this stress measurement method.The Japan Society of Mechanical Engineers, 04 Sep. 2010, The proceedings of the JSME annual meeting, 2010(Vol.8) (Vol.8), 255 - 256, Japanese
- Sep. 2010, 日本機械学会2010年度年次大会, 0, Japanese顕微ラマン分光を用いた単結晶シリコン振動子の局所応力解析
- Jul. 2010, The 5th Asia-Pacific Conference on Transducers and Micro-Nano Technology (APCOT2010),, p. 211, 211, EnglishSacrificial Microchannel Sealing by Glass-Frit Rflow for Micromachined Alkali Gas-Filled Cell[Refereed]
- 17 Jun. 2010, 電気学会マイクロマシン・センサシステム研究会資料, MSS-10(1-6.8-16.18-30) (1-6.8-16.18-30), 139 - 144, JapaneseHigh-Speed Mixing of Two Solutions using Alternate Pulsed Flow from Three Inlets Microchannels
- A tensile and tensile-mode-fatigue tester has been developed for testing microscale specimens in high humidity environments in order to investigate the fracture mechanisms of microelectromechanical materials. A humidity control system was installed on a tensile-mode fatigue tester equipped with an electrostatic force grip. A specimen and a griping device were inserted into a small chamber and the humidity was controlled by air flow from a temperature and humidity chamber. The humidity stability was within +/- 2%RH for humidities in the range 25-90%RH for eight hours of testing. Fatigue tests were performed on single-crystal silicon (SCS) specimens in constant humidity environments and laboratory air for up to 10(6) cycles. The gauge length, width, and thickness of the SCS specimens were 100 or 500 mu m, 13.0 mu m, and 3.3 mu m, respectively. The average tensile strength was 3.68 GPa in laboratory air; this value decreased in high humidity environments. Fatigue failure was observed during cyclic loading at stresses lower than the average strength. A reduction in the fatigue strength was observed at high relative humidities. Different fracture origins and fracture behaviors were observed in tensile tests and fatigue tests, which indicates that the water vapor in air affects the fatigue properties of SCS specimens.SPRINGER, Apr. 2010, EXPERIMENTAL MECHANICS, 50(4) (4), 509 - 516, English
- Mar. 2010, 第1回マイクロ・ナノ工学シンポジウム,, pp. 39-40, 39 - 40, Japanese単軸引張試験による単結晶シリコンの機械的特性の結晶異方性評価[Refereed]
- Jan. 2010, 2010 IEEE 5th International Conference on Nano/Micro Engineered and Molecular Systems, NEMS 2010, 245 - 249, English[Refereed]
- 2010, 7th Annual Conference on Foundations of Nanoscience: Self-Assembled Architectures and Devices, FNANO 2010, 11 - 12, EnglishDNA Mediated self-assembly of micro-scale components and sites[Refereed]
- This paper reports on a characterization of the developer-permeability of negative resist enabling a quick development of a complex microchannel network. The present development technique overcomes the diffusion limited process on the existing embedded microchannel fabrications, since the developer permeates the membrane region (channel ceiling) and the permeated developer dissolves uncross-linked photoresist under themembrane. In this paper, a primary feature of dependence of developer-permeability on process parameters was characterized by employing a cross-linking reaction model. Furthermore, microfluidic device with double-layered microchannel was demonstrated to show the usefulness of the proposed fabrication technique. (C) 2010 Published by Elsevier Ltd.ELSEVIER SCIENCE BV, 2010, EUROSENSORS XXIV CONFERENCE, 5, 854 - 857, English[Refereed]
- Among the current challenges of the tactile sensor for soft tissue stiffness detection is to get an output reading independent of the pushing distance between the senor and the tissue. Although a sensor with two probes configuration is used, the sensor output shows dependency on the pushing distance due to a cross talk effect between the two probes. To address this problem, a new compensation technique was proposed. It utilizes a tissue deformation effect in stiffness measurement to compensate the error due to cross talk effect between the two probes. A finite element analysis for the sensor output using ANSYS was carried out to investigate the dependency of cross talk effect on the separation distance between the two probes, It was confirmed that the cross talk effect and the error in stiffness measurement during tissue deformation can compensate each other. (C) 2009 Published by Elsevier Ltd.ELSEVIER SCIENCE BV, 2010, EUROSENSORS XXIV CONFERENCE, 5, 1304 - 1307, English[Refereed]
- Oct. 2009, APPIE 産学官連携フェア2009, 0, Japaneseマイクロリアクタによる金ナノ粒子合成技術を紹介します
- Oct. 2009, APPIE 産学官連携フェア2009, 0, Japaneseナノ粒子を所望のパターンに配列する
- Oct. 2009, 第26回センサ・マイクロマシンと応用システムシンポジウム,, pp. 533-538, 533 - 538, Japanese厚膜ネガレジストの埋め込み型流路作製のためのフォトリソグラフィ条件の決定手法[Refereed]
- Oct. 2009, 第26回センサ・マイクロマシンと応用システムシンポジウム,, pp. 483-486, 483 - 486, Japanese十字型混合流路による2液脈動混合の高速化[Refereed]
- Oct. 2009, 第26回センサ・マイクロマシンと応用システムシンポジウム,, pp. 518-523, 518 - 523, Japanese自己変位検出機能を有する面内2自由度静電櫛歯電極の等価回路[Refereed]
- This paper reports an electrical equivalent circuit model for describing in-plane two degree-of-freedom comb transducers. The proposed model is valid for any external parameters by building dummy spring into mis model to detect a mechanical displacement. As a result, we can analyze dc operating points by the model so that we need not to change the parameters of the model on changing the connected electrical and mechanical components, such as a dc bias, external force, and the stiffness of a spring. This model was adapted to a resonator and a frequency characteristic of 2DOF comb transducers was well represented by the model.The Japan Society of Mechanical Engineers, 12 Sep. 2009, The proceedings of the JSME annual meeting, 2009(8) (8), 69 - 70, Japanese
- 23 Jul. 2009, 電気学会マイクロマシン・センサシステム研究会資料, MSS-09(1-13) (1-13), 7 - 12, Japanese混合速度・温度制御可能な金ナノ粒子生成用マイクロリアクタ
- Jul. 2009, 平成21年度電気学会センサ・マイクロマシン部門総合研究会, 7 - 12, Japanese平成21年度電気学会センサ・マイクロマシン部門総合研究会
- 10 May 2009, 粉体工学会誌, 46(5) (5), 385 - 386, JapaneseReport on "First International Conference on Application of Intelligent Particles and Sensors in Environmental and Process Engineering"
- A differential capacitive three-axis silicon-on-insulator (SOI) accelerometer using vertical comb electrodes fabricated by using surface-micromachining technique has been developed. The accelerometer structures consist of only the device layer of a SOI wafer without lower or upper electrodes. The vertical comb electrodes of this device have structures different from conventional vertical comb electrodes. The bottom faces of both movable and fixed electrodes are in the same plane at their initial positions but their heights are different. Three-axis acceleration can be sensed with differential capacitance detection by using only these vertical comb electrodes. The device structures were successfully fabricated using self-alignment and Deep-RIE processes. As an initial result, the capacitance changes against three-axis acceleration were observed and the device sensitivities to three-axis accelerations were measured. The capacitance sensitivities of X, Y and Z-axis were 1.01, 0.898 and 0.989 fF/G, respectively. (C) 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.WILEY, May 2009, IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, 4(3) (3), 345 - 351, English
- Apr. 2009, International Conference on Electronics Packaging (ICEP2009),, pp. 959-962, 959 - 962, EnglishModeling of Self-face-alignment Process Using Contact Potential Difference[Refereed]
- Apr. 2009, Int Conf Electron Packag, 2009, 409 - 412, EnglishFabrication of Large-scale Nanoparticle Array Using Combination of Self-Assembly and 2-step Transfer[Refereed]
- 17 Mar. 2009, 電気学会全国大会講演論文集, 2009(3) (3), 182 - 183, Japanese静電容量型ＭＥＭＳデバイスを用いたカーボンナノ材料引張試験[Refereed]
- This paper presents a novel membrane design for capacitive micromachined ultrasonic transducers (cMUTs). The proposed design is composed of a thick membrane with reinforcing beams supported by a circumferential thin membrane to improve transducer sensitivity without degrading the membrane resonance frequency. Analytical formulation of sensitivity for the proposed design was newly derived and its validity was verified by finite element analysis (FEA). From the analysis, we confirmed that this thick membrane structure achieved three times higher sensitivity compared to the conventional design by decreasing 70% of the mass of the thick membrane part with keeping the resonance frequency same.ELSEVIER SCIENCE BV, 2009, PROCEEDINGS OF THE EUROSENSORS XXIII CONFERENCE, 1(1) (1), 389 - 392, English
- In this paper, we report tensile testing of a fullerene wire using an electrostatic MEMS device which can test nano-scale materials. We developed an electrostatic MEMS tensile testing device which has a comb drive actuator to apply tensile force to a specimen and two capacitances for measurement of the displacement to measure the elongation and applied force of the specimen. A free-standing fullerene wire which was about 16 μm long, 2μm wide and 40nm thick was integrated on the device and the tensile testing of the wire was successfully demonstrated with nano order resolutions. Measured Young's modulus and tensile strength of the wire were 5.9 GPa, 17 MPa, respectively. ©2009 IEEE.2009, TRANSDUCERS 2009 - 15th International Conference on Solid-State Sensors, Actuators and Microsystems, 2062 - 2065, English[Refereed]
- This paper reports on an optimization method for parameter sets for fabricating 3-dimensional microstructures in a single thick-film photoresist by the moving-mask UV lithography technique. The proposed optimization method employs the UV exposure calculation and the chemical behavior of chemically amplified negative-photoresist considering a cross-linking process during a thermal treatment of post-exposure bake to predict an optimum parameter range. In this paper, the validity of the proposed optimization method was successfully verified by evaluating a microchannel with "cm" length covered by a top-membrane and its dependence on the process parameter sets. ©2009 IEEE.2009, TRANSDUCERS 2009 - 15th International Conference on Solid-State Sensors, Actuators and Microsystems, 1616 - 1619, English[Refereed]
- We demonstrated that Deoxyribonucleic Acid (DNA) can be utilized as an intelligent adhesive activated by temperature control to realize sequential and selective self-assembly of 5 mm squared silicon micro components on a substrate. Two kinds of complementary DNA pairs whose melting transition temperature (T-m) and base sequence were designated appropriately were utilized to verify the feasibility of the proposed approach. It was successfully confirmed that sequential and selective assembly of micro components on the substrate can be realized below each Tm. Furthermore, DNA grafted polymer was proposed for the first time as a flexible spacer between micro components and a substrate to improve self-assembly yield and speed.IEEE, 2009, IEEE 22ND INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS 2009), 184 - 187, English[Refereed]
- We report a fabrication of doubly supported free-standing buckminsterfullerene (C(60)) nanowires onto single crystal silicon microstructures in order to demonstrate an integration of carbon nanomaterials to surface-micromachined microelectromechanical devices. By irradiating vacuum-deposited C(60) film with an electron beam, polymerized C(60) nanowires were patterned. Free-standing structures of the C60 nanowires were obtained by sacrificial etching of underlying silicon structures using XeF(2) gas. The supporting 5-mu m thick silicon structure was released using vapor hydrofluoric acid. The C(60) nanowire of 2-mu m width, 25-mu m length, and 40-nm thickness connected to a movable single crystal silicon structure was successfully fabricated. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3094745]SPIE-SOC PHOTOPTICAL INSTRUMENTATION ENGINEERS, Jan. 2009, JOURNAL OF MICRO-NANOLITHOGRAPHY MEMS AND MOEMS, 8(1) (1), English
- 22 Oct. 2008, Proc Sens Symp Sens Micromachines Appl Syst, 25th, 15 - 20, EnglishEffective Fabrication Method for Monolithic 3-dimensional Embedded Microstructure using the Moving-mask UV Lithography Technique[Refereed]
- Oct. 2008, The 12th International Conference on Miniturized Systems for Chemistry and Life Sciences,, pp. 730-732, 730 - 732, EnglishElectrical Equivalent Circuit Model of Microfluidic System Containing Piezoelectric Valveless Micropump and Viscoelastic PDMS Microchannnel[Refereed]
- Sep. 2008, The 22nd international conference EUROSENSORS (EUROSENSORS XXII),, pp. 1559-1602, 1559 - 1602, English3-dimensional Positive Thick-resist Microstructuring Adopting Wavelength Dependency of Photoresist Property[Refereed]
- 02 Aug. 2008, 日本機械学会年次大会講演論文集, 2008(Vol.8) (Vol.8), 23 - 24, Japaneseバルブレス圧電マイクロポンプと粘弾性マイクロ流路の電気等価回路[Refereed]
- Aug. 2008, 日本機械学会2008年度年次大会,8, pp. 157-158, 8, 157 - 158, Japanese単結晶シリコン引張試験における表面酸化の影響評価[Refereed]
- Jul. 2008, エレクトロニクス実装学会関西ワークショップ2008, 0, Japaneseセルフアセンブルによるマイクロ/ナノコンポーネントのMEMSへの集積化
- 12 Jun. 2008, 電気学会マイクロマシン・センサシステム研究会資料, MSS-08(1-21) (1-21), 1 - 6, Japaneseポジ型厚膜レジストの溶解速度の露光波長依存性と３次元加工への応用[Refereed]
- Jun. 2008, 平成20年度電気学会センサ・マイクロマシン部門総合研究会, 61 - 66, Japanese電気等価回路モデルによる高周波駆動バルブレス圧電マイクロポンプの特性解析
- A soft X-ray source with a periodic aluminum multilayer structure with vacuum layers in between for tabletop synchrotrons with low-energy electrons was designed, and the dependence of radiation performance on structural parameters was clarified using a theoretical calculation of the resonance transition radiation. A photon density of I keV pr incident electron was calculated by optimizing the thickness of the aluminum and vacuum layers. Furthermore, the designed structure was fabricated by a microfabrication technique. The effects of dimensional error on the photon density are discussed on the basis of the calculated results and the prototype structure of a 6-MeV synchrotron. It is clarified that dimensional errors of 1.5% in Al layers and of plus or minus a few dozen nanometers in the vacuum layers are negligible in obtaining a photon density of more than 90% of the maximum value. (c) 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.WILEY, May 2008, IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, 3(3) (3), 268 - 273, English
- Direct stiffness calibration of microelectromechanical-system (MEMS) springs made of single-crystal silicon was performed using a previously developed mechanical force measurement tool. The spring devices used for calibration were fabricated from silicon-on-insulator wafers and contained one or four folded-beam springs. The spring constants were directly measured using an electromagnetic force-feedback balance with a force resolution of about 0.2 mu N. The average measured spring constant of a folded-beam spring with a designed constant of 0.7 N/m was 0.58 N/m. This successful calibration shows that this tool can be used to calibrate various kinds of MEMS flexible structures. (C) 2007 Elsevier B.V. All rights reserved.ELSEVIER SCIENCE SA, May 2008, SENSORS AND ACTUATORS A-PHYSICAL, 143(1) (1), 136 - 142, English
- Apr. 2008, FNANO2008, 0, EnglishContact Potential Difference for Face Alignment of Submillimeter Components with Chemical Reaction Kinetics
- 2122 Self-Assembly Process using Electrostatic Adhesion Energy By Contact Electrification and its ModelingNovel self-assembly process using electrostatic adhesion energy induced by contact electrification phenomenon was proposed and its analytical formulation was performed for the first time. The contact electrification, which is observed when two different metals, such as platinum (Pt) - Silver (Ag) are contacted, was utilized to align a face of a component on a substrate. First, two types of 1 mm square silicon components with thickness of 0.5 mm coated with Pt or Ag and R substrate were prepared. Adhesion energies for two different metal pairs (Pt-Ag and Pt-Pt) were measured by measuring the vibration energy to separate the components from the vibrating substrate. The experimental results indicated the adhesion energy between Pt-Pt was 0.57 nJ, and Pt-Ag was 1.4 nJ on an average. Next, the face alignment experiment was carried out by vibrating the substrate on which 20 components with thickness of 0.2 mm were placed. The front and back face of the components were coated with R and Ag, respectively and they were split into half of R face up and the other half of Ag face up. We could get 83 % components were aligned as R face up. Finally, modeling of the proposed self-assembly process was performed based on the concept of chemical reaction formula. The forward and reverse reaction rates of the face alignment process were determined by fitting the foumula to the experimental data.The Japan Society of Mechanical Engineers, 17 Mar. 2008, Conference on Information, Intelligence and Precision Equipment : IIP, 2008, 271 - 274, Japanese
- 2121 Manipulation system for nano / micro components integration via transportation and self-assemblyWe developed, for the first time, the manipulation system based on optoelectronic tweezers (OET) which manipulates multiple nano/micro components on an arbitrary substrate with concurrent observation of the component motion. It uses CdS as a photoconductive film. Since CdS transmits red light and absorbs blue light, red light is utilized for the observation and blue light is utilized for the manipulation. The photoconductive electrode substrate which generates the nonuniform electric field for the component manipulation using dielectrophoresis consists of CdS on comb ITO electrode. Using the substrate, it was successfully demonstrated to manipulate a silica particle. Light projected CdS/ITO area had the higher electric field and repelled silica particle. By appling 10 V at 100 kHz, manipulation force of 0.6 pN was induced and manipulated silica particle speed was about 7 μm/s.The Japan Society of Mechanical Engineers, 17 Mar. 2008, Conference on Information, Intelligence and Precision Equipment : IIP, 2008, 269 - 270, Japanese
- Mar. 2008, 機械学会 情報・知能・精密機器部門(IIP部門)講演会, 0, Japanese微小コンポーネントの接触帯電によるセルフフェースアライメントプロセスのモデリング
- Mar. 2008, 機械学会 情報・知能・精密機器部門(IIP部門)講演会, 0, Japanese任意基板への微小要素の集積化のためのマニピュレーションシステム
- Mar. 2008, 電気学会全国大会,3, pp. 195-196, 3, 195 - 196, Japanese櫛歯型垂直変位電極を用いた基板面内軸回転検出振動型SOI ジャイロスコープ[Refereed]
- Mar. 2008, 電気学会全国大会,3, pp. 138-139, 3, 138 - 139, Japaneseレジスト現像特性の露光波長依存性を応用した厚膜レジストの３次元微細加工技術[Refereed]
- 2008, The 4th Asia Pacific Conference on Transducers and Micro/Nano Technologies (APCOT 2008), 0, EnglishY-AXIS VIBRATING SOI GYROSCOPE USING VERTICAL COMB ELECTRODES
- Effect of surface oxide layer on mechanical properties of single crystalline siliconThis paper reports on the tensile testing of single crystal silicon (SCS), whose specimen surface was intentionally oxidized, and the effect of the oxide thickness on the mechanical properties in order to investigate the fatigue fracture mechanism under cyclic loading. SCS specimens were fabricated from silicon-on-insulator (SOI) wafer with 3-mu m -thick device layer and oxide layer were grown to the specimens using thermal dry oxidation at 1100 degrees C. The specimen test part was 120 or 600 mu m long and 4 mu m wide. Quasi-static tensile testing of SCS specimen without oxide layer, with 100-nm-thick oxide, and with 200-mn-thick oxide was performed. As the results, the fracture origin location changed from the surface of the specimen of SCS without oxide to inside of silicon of oxidized specimen. This change may be caused by the smoothing of the surface and formation of oxide precipitation defects in silicon during oxidation. The estimated radius of the defects in specimen with 100 -nm-thick oxide and with 200-nm-thick oxide was 26 nm and 45 nm, respectively, which is well agreed with the fracture-initiating crack sizes calculated from the measured strengths.MATERIALS RESEARCH SOC, 2008, MICROELECTROMECHANICAL SYSTEMS - MATERIALS AND DEVICES, 1052, 53 - 58, English[Refereed]
- We demonstrated a new approach utilizing contact potential difference (CPD) based self-assembly for a future sequential assembly of nano/micro components and face alignment of submillimeter scale components. Two types of experiments realized by CPD were carried out 1) sequential assembly of silica particles using Coulomb force induced by contacting a Silver (Ag) probe on a Platinum (Pt) substrate, and 2) face alignment of component with Ag on one face and Pt on the other face on a Pt substrate by CPD induced additional electrostatic adhesive energy. In the face alignment experiment, the measured adhesive energies of two different metal pairs (Pt-Ag and Pt-Pt) were one order smaller than the theoretical value. However, 83 % components were successfully aligned as Pt face up. ©2008 IEEE.2008, Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), 1056 - 1059, English[Refereed]
- A novel sequential self-assembly process of nano/micro components applying deoxyribonucleic acid (DNA) hybridization was proposed for the first time and its validity was experimentally verified. In the proposed process, characteristics of DNA, such as hybridization specificity of complementary pairs of single-stranded DNA (ssDNA) into a double-stranded DNA (dsDNA), and the dependence of hybridization on ambient temperature (melting temperature T.) plays a key role. These characteristics of DNA can be designed and synthesized by base-pair sequence of DNA. Three types of self-assembly experiments using two types of ssDNA with different T,, (65 degrees C and 50 degrees C) were carried out; 1) between Au nanoparticles, 2) between An nanoparticle and Au coated substrate, and 3) between Silicon micro components (5 x 5 x 3 mu m(3)) and Au coated substrate. Through these experiments, it was successfully verified that the sequence of the self-assembly can be controlled by controlling the ambient temperature. The reversibility of this process was also confirmed. However, the Silicon micro components assembly on Au coated substrate was not confirmed.IEEE, 2008, MEMS 2008: 21ST IEEE INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS, TECHNICAL DIGEST, 1052 - 1055, English[Refereed]
- We successfully demonstrated a pattern formation of 60 nm gold nanoparticles using high productive combined technique of particle self-assembly and the assembled particle pattern transfer, and its availability for bio/chemical sensor with localized surface plasmon resonance (LSPR) of the patterned particles was verified. Dot and line patterns of nanoparticles were fabricated on a flexible PDMS substrate by proposed method. In addition, by measuring spectrums of assembled nanoparticle arrays, it was confirmed that the LSPR optical characteristic can be controlled by patterns of the assembled nanoparticles. ©2008 IEEE.2008, Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), 1048 - 1051, English[Refereed]
- We developed, for the first time, the manipulation system based on optoelectronic tweezers (OET) which manipulates multiple nano/micro components on an arbitrary substrate with concurrent observation of the component motion. From the theoretical analysis, the manipulation force of a hundred pN order is expected to act on components. It was successfully demonstrated to manipulate a PMMA particle of 10 μm diameter on a photoconductive film. ©2008 IEEE.2008, Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), 836 - 839, English[Refereed]
- This paper reports a fabrication of doubly-supported free-standing fullerene (C(60)) nanowires on MEMS structures to propose an integration process of carbon nano-materials to surface-micromachined silicon devices. By irradiating vacuum-deposited fullerene film with electron beam (EB), polymerized fullerene nanowires were patterned. Then, free-standing structures of the fullerene nanowires were obtained by sacrificial etching using XeF(2) gas. The fabricated fullerene nanowire was 2 mu m long, 400 nm wide and 15 nm thick.IEEE, 2008, MEMS 2008: 21ST IEEE INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS, TECHNICAL DIGEST, 689 - 692, English[Refereed]
- This paper presents a novel shape memory alloy (SMA) thin film actuator that has capability of vertical driving, miniaturization, and generating both large force and large displacement. We targeted a small tactile display which can reproduce a texture of an object to a fingertip, termed Smart Button, as a device for utilizing the proposed actuator performance effectively. An actuator for Smart Button has to achive displacement of dozens micron, output force of mN, output frequency of dozens Hz and an actuator pitch of less than 1 mm. The actuator structure of TiNi/SiO2 bi-material beam structure with flexible fixed ends is proposed for performing the requirements. The structural dependences of the displacement and generating force of the actuator were analyzed by FEM. As a result, the validity of the proposed design concept and the configuration of the actuator for Smart Button was successfully confirmed. © 2008 The Institute of Electrical Engineers of Japan.2008, IEEJ Transactions on Sensors and Micromachines, 128(4) (4), 6 - 160, Japanese
- A detailed design procedure for a tactile sensor for compliance detection is developed. The sensor principle is based on the concept of applying two springs, with considerably different stiffnesses, to soft tissue for compliance detection. The spring stiffnesses are chosen to be associated with the soft tissue properties. The sensor design parameters are optimized to give high sensitivity and linearity of the sensor output with taking into account the effect of crosstalk between two springs due to the tissue deformation. A finite element model is developed to investigate the sensor performance with the designed parameters using two types of spring end, namely cubic and spherical in shape. The results show a significant stability of reading with the cubic end rather than the spherical one during pushing the sensor against a tissue. Finally, the same finite element model is used with changing the distance between the spring ends to show the crosstalk effect due to the tissue deformation. © 2008 The Institute of Electrical Engineers of Japan.2008, IEEJ Transactions on Sensors and Micromachines, 128(5) (5), 186 - 192, English
- We theoretically and experimentally evaluated the damping effect in a rotational resonator with a comb-drive actuator and sensor. The resonator was fabricated from an SOI wafer and has a fan-shaped mass. The underlying substrate was removed using back side deep reactive ion etching. One set of comb electrodes was attached to each side of the mass: one for electrostatic driving and the other for capacitive detection. In our theoretical analysis, the dynamics of the resonator were simplified so that they could be represented by a lumped system. In this lumped system, the damping coefficient was estimated by assuming the damping to be slide film damping and the air flow to be a Stokes flow. The phase shift due to the slide film damping of thick air layers was included in the lumped system. In the experimental evaluation, one side of the rotational combs was removed step-by-step and a half of the mass using a laser trimming tool so that the individual damping effects caused by the comb electrodes and mass could be determined quantitatively. We compared the experimental results with the results of the theoretical analysis and found that the difference in the damping coefficients between the experimental results and results of the theoretical analysis was less than 40%. © 2008 The Institute of Electrical Engineers of Japan.2008, IEEJ Transactions on Sensors and Micromachines, 128(5) (5), 203 - 208, English
- 16 Oct. 2007, Proc Sens Symp Sens Micromachines Appl Syst, 24th, 165 - 168, EnglishEffect of surface oxidation on mechanical properties of single crystalline silicon[Refereed]
- Novel self-assembly process using electrostatic adhesion energy induced by contact electrification phenomenon is proposed for the first time. The contact electrification, which is observed when two different metals, such as platinum (Pt)-Silver (Ag) are contacted, was utilized to align a face of a component on a substrate. Two types of 1mm square silicon components with thickness of 0.5mm coated with Pt or Ag and Pt substrate were prepared. Adhesion energies for two different metal pairs (Pt-Ag and Pt-Pt) were measured by measuring the vibration energy to separate the components from the vibrating substrate. The experimental results indicated the adhesion energy between Pt-Pt was 0.57nJ, and Pt-Ag was 1.4nJ on an average. Secondly, the face alignment experiment was carried out by vibrating the substrate on which 20 components with thickness of 0.2mm were placed. The front and back face of the components were coated with Pt and Ag, respectively and they were split into half of Pt face up and the other half of Ag face up. Finally, we could get 83% components were aligned as Pt face up.The Japan Society of Mechanical Engineers, Sep. 2007, The proceedings of the JSME annual meeting, 2007, 313 - 314, Japanese
- Sep. 2007, 日本機械学会2007年度年次大会, 307 - 308, Japanese低侵襲触覚センサーの構造設計
- Sep. 2007, 日本機械学会2007年度年次大会, 303 - 304, Japanese移動マスクUV露光法によるポジ型厚幕レジストの3次元加工と形状シミュレーション技術
- Aug. 2007, 粉体工学会第43回夏期シンポジウム, 52 - 53, Japaneseナノテンプレートを用いたセルフアセンブルによる粒子パターン形成
- Aug. 2007, 粉体工学会第43回夏期シンポジウム,, pp. 19-20, 19 - 20, JapaneseDNAの選択性およい温度特性を利用したAuナノ微粒子のセルフアセンブル[Refereed]
- Jul. 2007, 電気学会総合研究会, 2007(1) (1), 79 - 84, JapaneseFlow Analysis of Valveless Piezoelectric Micropump with Electrical Equivalent Circuit Model and Its Experimental Validation
- Jul. 2007, 電気学会総合研究会, 2007(1) (1), 19 - 24, JapaneseDevelopment profile simulation tool adopting Fast Marching Method for the Moving-mask UV lithography method
- Jun. 2007, 化学とマイクロシステム, 0, Japaneseマイクロ流体デバイスを用いた混合速度制御による金ナノ粒子作製
- We propose a method of submicroparticle pattern formation with high productivity, flexibility, and accuracy. The proposed process is composed of template-assisted self-assembly for particle self-assembly and a subsequent two-step transfer of the assembled particles. Optimization of the process parameters was performed by carrying out experiments to evaluate the effects of the parameters on the yields of each process. Polystyrene particles that are 500 nm in diameter were used, and a silicon wafer was used as a target substrate in the experiments that are described in this paper. In the self-assembly process, 70% of the pattern was successfully self-assembled on a silicon template substrate. In the first transfer step, a transfer yield of 79% was obtained with a self-assembled-monolayer-coated polydimethylsiloxane carrier substrate. In the second transfer step, a transfer temperature of 115 degrees C provided the maximum transfer yield of 85%. The overall process yield of 48% was achieved by the optimized process parameters, and it was successfully demonstrated that the proposed method can fabricate any submicroparticle pattern.IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Jun. 2007, JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, 16(3) (3), 746 - 752, English
- 1119 Tensile Testing of Carbon Nano Materials using Electrostatic MEMS DeviceA new on-chip tensile testing device using electrostatic actuation and detection was designed and fabricated from an SOI wafer to evaluate the mechanical properties of carbon nano materials such as carbon nano-tubes and fullerenes. In this device, force is generated by electrostatic comb drive actuator and tensile force on specimen is measured as the deformation of force-measuring spring. The specimen elongation and the spring deformation are detected as capacitance changes. As a result of design, we predicted high resolution of elongation and tensile force, which are 1nm and 1nN respectively. In order to assemble carbon nano-material on this device, a new technique for fabricating a free-standing fullerene nano-wire was proposed. This wire was fabricated using electron beam writing and sacrificial dry etching. By irradiated vacuum-deposited fullerene thin film with electron beam, polymerized fullerene nano-wires were patterned. Then, the doubly-supported beam structure of the fullerene nano-wire was obtained by sacrificial dry etching using XeF_2 gas.The Japan Society of Mechanical Engineers, 19 Mar. 2007, Conference on Information, Intelligence and Precision Equipment : IIP, 2007, 66 - 69, Japanese
- Mar. 2007, 平成19年，電気学会全国大会, 181 - 182, Japanese移動マスクUV露光法による埋め込み型流路の作製
- Mar. 2007, 文部科学省ナノテクノロジー総合支援プロジェクト「分子・物質総合合成・解析支援グループ」成果発表会, 82 - 83, JapaneseDNA修飾した微小コンポーネントのシーケンシャルセルフアセンブリ
- Mar. 2007, 文部科学省ナノテクノロジー総合支援プロジェクト「分子・物質総合合成・解析支援グループ」成果発表会, 82 - 83, JapaneseEB描画によるナノパターンを用いたナノ粒子アセンブル
- Mar. 2007, 日本機械学会情報・知能・精密機器部門講演会, 0, Japanese静電容量型MEMS デバイスを用いたカーボンナノ材料引張試験
- This paper presents a systematic study on a novel 3D (three-dimensional) UV (ultraviolet) lithography apparatus for thick photoresist and a UV lithography process simulation for 3D microstructuring. In order to realize a wide variety of 3D microstructures, the developed proximity 3D UV lithography apparatus adopts the 'moving mask lithography' concept which was originally proposed by the authors for deep x-ray lithography. Furthermore, the authors propose a new practical photoresist profile simulation approach adopting the 'fast marching method' to consider the photoresist dissolution vector in the development process. A series of moving mask UV lithography experiments using a positive-tone photoresist (50 mu m thickness) successfully confirmed (1) the capability of the moving mask UV exposure technique for 3D microstructuring and (2) the validity of the proposed photoresist profile simulation.IOP PUBLISHING LTD, Feb. 2007, JOURNAL OF MICROMECHANICS AND MICROENGINEERING, 17(2) (2), 199 - 206, English
- 2007, Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), 267 - 270, EnglishTensile-mode fatigue tests and fatigue life predictions of single crystal silicon in humidity controlled environments[Refereed]
- Mechanical calibration of MEMS spring with 0.1-mu N force resolutionThe direct calibration of MEMS springs made of single crystal silicon was carried out using a mechanical force measurement tool. The spring device for calibration fabricated from silicon on insulator (SOI) wafer contains four folded-beam springs. The spring constants of different-length devices were directly measured using electromagnetic force-feedback balance, whose force resolution was about 0.2 mu N. The spring constants of the two types of folded-beam springs, whose designed constant was 0.3 and 0.7 N/m, were 0.18 and 0.57 N/m, respectively. The spring constants were successfully calibrated, which shows that this tool can calibrate various kinds of MEMS flexible structures.IEEE, 2007, PROCEEDINGS OF THE IEEE TWENTIETH ANNUAL INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS, VOLS 1 AND 2, 21 - 24, English[Refereed]
- A soft X-ray source with a periodic Al multi-layer structure for a tabletop synchrotron was designed and the dependence of radiation performance on structural parameters was clarified by using a theoretical calculation of resonance transition radiation. The spectral intensity of photon per incident electron at emitted photon of 1 keV was calculated by optimizing the Al thickness and vacuum space. Furthermore the designed structure was fabricated by microfabrication technique. Based on the fabrication results, we discussed dimension errors of Al thickness and vacuum space. It was confirmed that the vacuum space should be ranged from 90 nm to 140 nm to obtain the spatial total intensity of more than 90 percents of the maximum value of radiation intensity. © 2007 American Institute of Physics.2007, AIP Conference Proceedings, 902, 121 - 124, English[Refereed]
- This paper reports on the development of a new tensile tester operable at 800 degrees C using IR heating system for evaluating mechanical properties of thin films at high temperature. Single crystal silicon films of 3 mu m thick were tested at 600 degrees C. At room temperature, the fracture strength and Young's modulus were 3.33 GPa and 163.2 GPa, respectively. At 600 degrees C, they were 2.71 GPa and 151.8 GPa, respectively. When the strain rate was decreased, the stress and stage displacement curves had yield points and the fractured specimens exhibited the slip lines at 600 degrees C.IEEE, 2007, TRANSDUCERS '07 & EUROSENSORS XXI, DIGEST OF TECHNICAL PAPERS, VOLS 1 AND 2, 571 - 574, English[Refereed]
- An improved equivalent circuit model for effective calculation of a valveless piezoelectric micropump performance which is operated by a dependency of flow resistance on flow rate was proposed. The validity of the proposed model was evaluated by comparing the dynamic flow behavior calculated by the equivalent circuit model with mu-PIV measurement. From the good agreements between the analysis and the experimental results, it was concluded that a dynamic flow characteristic with microsecond scale of the micropump was able to be analyzed precisely by the developed equivalent circuit model.IEEE, 2007, TRANSDUCERS '07 & EUROSENSORS XXI, DIGEST OF TECHNICAL PAPERS, VOLS 1 AND 2, 2183 - 2186, English[Refereed]
- This paper presents a systematic study on "Moving-mask UV lithography" for 3-D (three-dimensional) microstructuring of positive- and negative-tone thick photoresist and a dedicated UV lithography process simulation. As an application of the moving-mask UV lithography, we propose a novel method to fabricate embedded microfluidic structures Using SU-8. Furthermore, we propose a new practical photoresist profile simulation approach adopting the "Fast Marching Method" to consider the photoresist dissolution vector in the development process. Through a series of moving-mask UV lithography experiments, (1) the capability of the moving-mask UV lithography for 3-D microstructuring, and (2) the validity of the proposed photoresist profile simulation, were successfully confirmed.IEEE, 2007, TRANSDUCERS '07 & EUROSENSORS XXI, DIGEST OF TECHNICAL PAPERS, VOLS 1 AND 2, 545 - 548, English[Refereed]
- This paper reports a differentially detecting capacitive three-axis SOI accelerometer using novel vertical comb electrodes. The accelerometer structure was fabricated by surface-micromachining technique and consists of only the device layer of a SOI wafer without lower or upper electrodes. The bottom faces of both movable and fixed electrodes are in the same plane at their initial positions but those heights are different. It is also an important feature that the device applies fully differential detections in all three-axis by using only two pairs of four type capacitors. As an initial result, the capacitance changes against three-axis acceleration were observed. The capacitance sensitivities to X and Z-axis acceleration against Y-axis rotation were 1.04 fF/G and 1.14 fF/G, respectively. ©2007 IEEE.2007, TRANSDUCERS and EUROSENSORS '07 - 4th International Conference on Solid-State Sensors, Actuators and Microsystems, 1483 - 1486, English[Refereed]
- in this paper, a new temperature controlled sequential stacking self-assembly technique is proposed. This method utilizes capillary force generated by two different liquid of TEGDMA (Triethyleneglycol Dimethacrylate) and 42Sn-58Bi solder as adhesives. TEGDMA with an additional thermal initiator is liquid at room temperature and hardens by heat. 42Sn-58Bi solder is solid at room temperature and melts at 138 degrees C. Since TEGDMA and 42Sn-58Bi solder are selectively utilized as adhesives by setting the process temperature at room temperature for TEGDMA and 150 degrees C for 42Sn-58Bi solder, the sequential self-assembly of different components can be realized. The feasibility of the proposed process and alignment accuracy are experimentally and theoretically examined using 1 mm square silicon chips as test components. The first component assembly on a substrate is carried out at room temperature using TEGDMA, and the second component assembly on the assembled component is carried out at 150 degrees C using 42Sn-58Bi solder Both assembly steps are carried out in EG (Ethylene Glycol) solvent with an additional sulfuric acid. It was confirmed that the first and the second assembly were successfully done at room temperature and at 150 degrees C, and alignment accuracy of the first and the second assembly were 33 mu m and a few pm, respectively.IEEE, 2007, 6TH INTERNATIONAL IEEE CONFERENCE ON POLYMERS AND ADHESIVES IN MICROELECTRONICS AND PHOTONICS, PROCEEDINGS 2007, 128 - +, English[Refereed]
- In this paper, a new sequential stacking self-assembly using interfacial tension of two different droplets of TEGDMA (Triethyleneglycol Dimethacrylate) and 42Sn-58Bi solder was proposed. TEGDMA with an additional thermal initiator is liquid at room temperature and hardens by heat. 42Sn-58Bi solder is solid at room temperature and melts at 138 °C. Since interfacial tension of TEGDMA and 42Sn-58Bi solder are selectively utilized by setting the process temperature at room temperature for TEGDMA and 150 °C for 42Sn-58Bi solder, the sequential self-assembly of different components can be realized. The feasibility of the proposed process and alignment accuracy were experimentally examined using 1 mm square silicon chips as test components. The first component assembly on a substrate was carried out at room temperature using TEGDMA as an adhesive agent, and the second component assembly on the assembled component was carried out at 150 °C using 42Sn-58Bi solder as an adhesive agent. Both self-assembly processes were carried out in EG (Ethylene Glycol) solvent with an additional sulfuric acid. It was confirmed that the first and second self-assembly was successfully done at room temperature and at 150 °C, and alignment accuracy of first and second self-assembly were 33 μm and a few μm, respectively.The Institute of Electrical Engineers of Japan, 2007, The Journal of the Institute of Electrical Engineers of Japan, 127(4) (4), 214 - 220, Japanese
- Dec. 2006, 第50回日本学術会議材料工学連合講演会, 0, Japanese単層カーボンナノチューブ引張試験のための静電容量型MEMS デバイスの構造設計
- Dec. 2006, 第50回日本学術会議材料工学連合講演会, 0, Japanese高温薄膜引張試験機の試作および単結晶シリコン薄膜の物性評価
- 05 Oct. 2006, Proc Sens Symp Sens Micromachines Appl Syst, 23rd, 19 - 22, EnglishSub-Micro Particles Patterning Using Self-Assembly and Two-Step Printing[Refereed]
- 05 Oct. 2006, Proc Sens Symp Sens Micromachines Appl Syst, 23rd, 471 - 476, EnglishA differential capacitive three-axis SOI accelerometer using vertical comb electrodes[Refereed]
- Oct. 2006, Proceedings of the 23rd Sensor Symposium, 471 - 476, Japanese移動マスクUV露光法による厚膜レジストの三次元微細加工技術
- Sep. 2006, 日本機械学会2006年年次大会, 0, Japanese電磁式天秤を用いたマイクロ構造のバネ定数測定
- May 2006, 電気学会E部門総合研究会, MSS-06-18, 83 - 87, Japanese薄膜材料の高温引張試験に関する基礎検討
- Mar. 2006, 電気学会全国大会, 3, 198 - 199, Japanese単結晶シリコン薄膜の環境制御引張疲労試験
- Vertical drive micro actuator using SMA thin film for a smart buttonThis paper presents the performance of a shape memory alloy (SMA) thin film micro-actuator for a small tactile display to reproduce an object texture to a fingertip. Maximum displacement of 30 mu m under 4.2 mN load with an actuator length of 1 mm, which fulfills the minimum requirements for reproducing a texture to a fingertip, is realized by the newly proposed SMA thin film actuator structure.IEEE, 2006, MEMS 2006: 19TH IEEE INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS, TECHNICAL DIGEST, 2006, 734 - 737, English[Refereed]
- 2006, Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), 2006, 546 - 549, EnglishFabrication of gold nanoparticle using pulsed mixing method with valveless micropumps[Refereed]
- Oct. 2005, PROCEEDINGS OF THE 22ND SENSOR SYMPOSIUM, 311 - 315, EnglishTensile-Mode Fatigue Test of Single Crystal Silicon Thin Films Using Electrostatic Grip
- Oct. 2005, PROCEEDINGS OF THE 22ND SENSOR SYMPOSIUM, 329 - 332, EnglishGold Nanoparticles Synthesis With Pulsed Mixing Method
- Jun. 2005, 電気学会E部門総合研究会, 2005(21) (21), 57 - 62, JapaneseParticle Adhesion Forces Measurements in Solutions for Particle Assemble
- We present a new rapid prototyping technique without a photolithography step to produce a glass chip with high aspect ratio channel for a micro total analysis system (mu TAS). This technique consists of a powder blasting technique and direct laser patterning of Au nanoparticles dispersed polymer mask technique, and is useful in the development stage of a glass chip. The mask thickness and powder blasting condition were optimized for the fabrication of a glass chip with a higher aspect ratio channel. Under the optimized processing condition, the microchannel with a maximum aspect ratio of 2.1 in a glass substrate was successfully realized. The proposed technique was applied to a glass chip for electrophoresis and its performance for DNA separation analysis was confirmed.IOP PUBLISHING LTD, Jun. 2005, JOURNAL OF MICROMECHANICS AND MICROENGINEERING, 15(6) (6), 1236 - 1241, English
- 10 Mar. 2005, 電気学会研究会資料. MSS, マイクロマシン・センサシステム研究会, 2005(1) (1), 49 - 54, JapaneseFabrication of Silicon Mold for Hot Embossing using ICP-RIE
- Jul. 2004, Asia-Pacific Conference of Transducers and Micro-Nano Technology, 547 - 552, EnglishSimulation of Surface Roughness in Si Etching with XeF
- 2004, 第21回「センサ・マイクロマシンと応用システム」シンポジウム, 483 - 488, JapaneseSimulation of Surface Roughness in Si Etching with XeF2
- 2004, 電気学会E部門総合研究会, 75 - 80, Japaneseマイクロブラストを用いたμ-TASガラスチップの作製
- Rapid prototyping of glass chip with micro-powder blasting using nano-particles dispersed polymerWe present a new rapid prototyping technique to produce a glass chip with high aspect ratio channel for micro total analysis system (muTAS). This technique consists of powder blasting technique and laser patterning of newly developed Au nano-particles dispersed polymer mask. The microchannel with maximum aspect ratio of 2.1 in a glass substrate was successftilly realized without photolithography step. The proposed technique was applied to a glass chip for electrophoresis and its performance for DNA separation analysis was confirmed. Furthermore, the micro-powder blasting technique with elevated temperature of Au nano-particles dispersed polymer mask was proposed for the first time.IEEE, 2004, MEMS 2004: 17TH IEEE INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS, TECHNICAL DIGEST, 697 - 700, English[Refereed]
- 2003, 電気学会研究会資料，マイクロマシン・センサシステム研究会, MSS-03-35, 35 - 39, Japaneseマイクロマシニングを用いた軟Ｘ線遷移放射ターゲット
- Low etching pressure and addition of buffer gas successfully decrease the etched surface roughness and the aperture effect which represent challenges toward the application of silicon etching with XeF2 to MEMS fabrication. Etched roughness and aperture effect are extremely high and limit factors for the design rules of MEMS. By lowering the charge pressure of XeF2 from 390 to 65 Pa, the etched roughness decreased from 870.8 and 174.4 Å and the uniformity ((depth for 25 μm mask aperture)/(depth for 175 μm mask aperture) × 100 %) improved from 71.3 to 88.7%. By adding N2 or reaction products including Xe and SiF4 as buffer gas, surface roughness was reduced and the surface morphology changed.2003, Proceedings of SPIE - The International Society for Optical Engineering, 4979, 62 - 69, English[Refereed]
- Low etching pressure and high silicon substrate temperature successfully decrease the etched surface roughness and the aperture size effect, which represent challenges to the application of silicon etching with XeF2 to the fabrication of microelectromechanical systems (MEMS). The etched roughness and aperture size effect are extremely high and limit factors for the design rules of MEMS devices. In order to express the extent of the aperture size effect, a uniformity of etched depth is defined as follows: (depth at 25 μm)/(depth at 175 μm) × 100%. By lowering the charge pressure from 390 to 65 Pa, the etched roughness decreased from 870.8 and 174.4 Å and the uniformity improved from 71.3 to 88.7%. By increasing the substrate temperature from 300 to 440 K, the etched roughness decreased from 151.4 and 44.5 Å and the uniformity increased from 71.3 to 91.6%. These results will allow us to design with fewer constraints and to expand the field of applications of XeF2 etching to MEMS.Nov. 2002, Journal of Micromechanics and Microengineering, 12(6) (6), 911 - 916, English
- We developed a XeF2 pulse etching system and clarified the Si etching characteristics. Dependencies of Si etching rates and etched roughness on the crystallographic orientation, number of pulses, pulse duration time, aperture size and etching pressure were measured. An etching depth and an etched roughness were 12.9 mum and 115 nm, respectively under charge pressure of 390 Pa, a pulse number of 10 and pulse duration time of 60 s. The etching depth increased by 36% with increasing the aperture width from 25 to 175 mum. This aperture size effect decreased from 36 to 20% with decreasing charge pressure from 390 to 65 Pa. The etched roughness decreases also with decreasing the etching pressure. The roughness was 25 nm under the charge pressure of 65 Pa, 50 pulses, 60 s.SPRINGER, Nov. 2002, MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS, 9(1-2) (1-2), 11 - 16, English
- Low etching pressure and high temperature on silicon substrate successfully decrease the etched surface roughness and the aperture effect which represent challenges toward the application of silicon etching with XeF2 to MEMS fabrication. Etched roughness and aperture effect are extremely high and limit factors for the design rules of MEMS devices. In order to express an extent of the aperture effect, an uniformity of etched depth is defined as follow: (Depth at 25 mum)/(Depth at 175 mum)X100%. By lowering the charge pressure from 390 to 65 Pa, the etched roughness decreased from 870.8 and 174.4 Angstrom and the uniformity improved from 71.3 to 88.7%. By heightening the substrate temperature from 300 to 440 V, the etched roughness decreased from 151.4 and 44.5 Angstrom and the uniformity increased from 71.3 to 91.6%. These results will allow us to design with less constrained and expand the field of applications of XeF2 etching to MEMS.IEEE, 2002, MHS2002: PROCEEDINGS OF THE 2002 INTERNATIONAL SYMPOSIUM ON MICROMECHATRONICS AND HUMAN SCIENCE, 47 - 52, English
- 2002, 第19回「センサ・マイクロマシンと応用システム」シンポジウム, 303 - 308, JapaneseXeF2 を用いたSi エッチングにおける表面粗さと加工深さの制御
- 2001, マイクロマシニング研究会, 0, JapaneseXeF2エッチングにおけるエッチング特性と紫外線照射によるマスク材のエッチレート制御
- A new technique to control etching rates of mask materials during XeF2 etching was proposed. By exposing Si sample with SiO2 and Si3N4 as mask materials to UV light of 3 W/cm2 during XeF2 etching, the etching rates of SiO2 and Si3N4 were dramatically increased from 2.52 Å/pulse to 42.0 Å/pulse and from 27.3 Å/pulse to 403 Å/pulse, respectively. This new technique allows us to remove the mask material selectively and change the mask pattern by UV light exposure during in-situ etching process without additional photolithography step and opens a new silicon micromachining process for 3-dimensional fabrication. The multi-step Si structure was successfully realized by this technique.2001, Proceedings of SPIE-The International Society for Optical Engineering, 4557, 18 - 23, English[Refereed]
- 2001, 電気学会センサ・マイクロマシン準部門論文誌, Vol.121-E, No.12, pp.327-332Selectivity Control of Mask Material for XeF2 Etching Using UV light Exposure
- 2001, 電気学会センサ・マイクロマシン準部門論文誌, Vol.121-E, No.12, pp.327-332Selectivity Control of Mask Material for XeF2 Etching Using UV light Exposure
- 2000, Proceedings of the International Symposium on Micro Machine and Human Science, 89 - 94, EnglishEffects of etching pressure and aperture width on Si etching with XeF2[Refereed]
- 1999, Proceedings of the International Symposium on Micro Machine and Human Science, 163 - 167, EnglishStudy on XeF2 pulse etching using wagon wheel pattern[Refereed]
- 第36回「センサ・マイクロマシンと応用システム」シンポジウム, Nov. 2020, Japanese静電型マイクロ振動子トランスデューサを用いたシリコン近赤外光強度センサPoster presentation
- 33rd International Microprocesses and Nanotechnology Conference (MNC2020), Nov. 2020, EnglishElectrical and Optical Characterization of Nanogap Electrodes with an Assembled Gold Nanoparticle ChainOral presentation
- 33rd International Microprocesses and Nanotechnology Conference (MNC2020), Nov. 2020, EnglishGrowth Direction of VLS Silicon Nanowires with Surface Nanoholes Formed Using MACEOral presentation
- 第37回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2020, Japaneseマイクロ振動子のたわみ制御による振動型光センサの高感度化Oral presentation
- 第37回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2020, Japanese⾦ナノ構造光吸収体集積静電型マイクロ振動⼦デバイスによる近⾚外光強度センシングPoster presentation
- 第37回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2020, Japanese光センシングマイクロ共振デバイスの梁長さおよび振幅が計測分解能に与える影響Oral presentation
- 第37回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2020, Japanese高温パンチクリープ成形技術を用いた3軸力覚センサの開発および被覆樹脂の粘弾性特性を考慮したセンサ性能評価Oral presentation
- 第37回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2020, Japanese金ナノ構造を用いた波長依存性を有するSOI型近赤外ボロメータ素子Oral presentation
- 第37回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2020, Japanese金ナノ粒子二量体を用いたナノギャップ電極の作製とその電気的・光学的評価Oral presentation
- 第37回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2020, Japanese近赤外吸収体を有する静電型マイクロ振動子デバイスを用いた水の分光測定Oral presentation
- 第36回「センサ・マイクロマシンと応用システム」シンポジウム, Nov. 2019, Japaneseシリコンマイクロ振動子光センサにおける共振周波数特性の形状依存性Poster presentation
- 第36回「センサ・マイクロマシンと応用システム」シンポジウム, Nov. 2019, Japanese架橋成長Si ナノワイヤの熱電特性評価に関する研究Poster presentation
- 第36回「センサ・マイクロマシンと応用システム」シンポジウム, Nov. 2019, JapaneseコアシェルSiC ナノワイヤの電気伝導性に及ぼすシェル表面電位Poster presentation
- 第36回「センサ・マイクロマシンと応用システム」シンポジウム, Nov. 2019, Japanese金ナノグレーティング構造の光吸収ピーク波長制御による高感度レーザ波長計測マイクロ振動子デバイスPoster presentation
- 第36回「センサ・マイクロマシンと応用システム」シンポジウム, Nov. 2019, Japanese光励起ナノギャップ電極を用いたDNA オリゴマーの光トラップおよび1 分子検出Oral presentation
- 第36回「センサ・マイクロマシンと応用システム」シンポジウム, Nov. 2019, Japanese金ナノ粒子二量体表面増強ラマン分光によるDNA オリゴマーの1 塩基検出Poster presentation
- 32nd International Microprocesses and Nanotechnology Conference (MNC2019), Oct. 2019, EnglishEvaluation of Thermoelectric Properties of VLS-Grown Bridged Si NanowirePoster presentation
- 32nd International Microprocesses and Nanotechnology Conference (MNC2019), Oct. 2019, EnglishNear-Infrared Light Absorbers Using Si-Deposited Gold Nanowire Grating StructuresPoster presentation
- 32nd International Microprocesses and Nanotechnology Conference (MNC2019), Oct. 2019, EnglishEffect of The Numbers of Beams and Corners on Resonant Frequency Response of Silicon Microresonator to Near-Infrared-Light Irradiation for Optical SensingPoster presentation
- 32nd International Microprocesses and Nanotechnology Conference (MNC2019), Oct. 2019, EnglishEffect of Gold Nanoparticle Diameter on Raman Intensity of DNA Oligomers toward Single Nucleobase DetectionOral presentation
- 32nd International Microprocesses and Nanotechnology Conference (MNC2019), Oct. 2019, EnglishMicroresonator-Based Photodetector of Near-Infrared Light Using Electrostatic TransducersOral presentation
- 2019 International Conference on Optical MEMS and Nanophotonics (IEEE OMN 2019), Aug. 2019, EnglishSingle-molecule Surface Enhanced Raman Spectroscopy Using Gold Nanoparticle Dimer[Invited]Invited oral presentation
- The 19th IEEE International Conference on Nanotechnology (IEEE-NANO2019), Jul. 2019, EnglishSurface-Enhanced Raman Spectroscopy of DNA with Single-Molecule Sensitivity Using Gold Nanoparticle Dimer[Invited]Invited oral presentation
- The 20th International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers2019), Jun. 2019, EnglishSERS detection of a single nucleobase in a DNA oligomer using gold nanoparticle dimerPoster presentation
- The 20th International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers2019), Jun. 2019, EnglishManipulation of biomolecules into nanogap by plasmonic optical excitation for highly sensitive biosensingOral presentation
- 31st International Microprocesses and Nanotechnology Conference (MNC2018), Nov. 2018, English, International conferenceSurface-Enhanced Raman Spectroscopy of DNA Bases Using Gold Nanoparticle Dimer ArrayPoster presentation
- 31st International Microprocesses and Nanotechnology Conference (MNC2018), Nov. 2018, English, International conferenceDevelopment of 3D Formed Tactile Sensor by High Temperature Punch Creep Forming TechniqueOral presentation
- 第35回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2018, Japanese, Domestic conferenceVLS成長SiNW単体に対する熱電変換特性評価Poster presentation
- 第35回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2018, Japanese, Domestic conferenceSi薄膜被覆金ナノグレーティング構造の近赤外域光吸収スペクトル偏光依存性Poster presentation
- 日本材料学会マルチスケール材料力学シンポジウム, May 2018, Japanese, Domestic conference単結晶シリコン薄膜の高温パンチクリープ成形による極小3軸力覚センサの開発Oral presentation
- The 31st IEEE International Conference on Micro Electro Mechanical Systems (MEMS2018), Jan. 2018, English, International conferenceA Novel 3-axis Tiny Tactile Sensor Developed by 3-D Microstructuring Using Punch Creep Forming ProcessPoster presentation
- 30th International Microprocesses and Nanotechnology Conference (MNC2017), Nov. 2017, English, International conferenceSurface-Enhanced Raman Spectroscopy of Adenine Molecule Using Single Dimer of Gold NanoparticlesPoster presentation
- 30th International Microprocesses and Nanotechnology Conference (MNC2017), Nov. 2017, English, International conferenceLaser Wavelength Measurement Using Gold Nanoparticle Aggregate Integrated MicroresonatorOral presentation
- 第34回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2017, Japanese, Domestic conference単一金ナノ粒子二量体を用いた表面増強ラマン分光によるDNAオリゴマー1分子検出Oral presentation
- 第34回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2017, Japanese, Domestic conference高温クリープ立体成形技術による極小MEMS触覚センサの開発研究Poster presentation
- 第34回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2017, Japanese, Domestic conferenceSi薄膜被覆金ナノワイヤグレーティング構造の近赤外域光学特性評価Poster presentation
- 14th International Conference on Fracture, Jun. 2017, English, International conferenceEvaluation of mechano-electric properties for VLS-grown core/shell silicon carbide nanowiresOral presentation
- 日本材料学会マルチスケール材料力学シンポジウム, May 2017, Japanese, Domestic conferenceVLS成長Core/Shell-SiCナノワイヤのピエゾ抵抗効果に及ぼすSiO2被覆の影響Poster presentation
- 平成29年電気学会全国大会, Mar. 2017, Japanese, Domestic conferenceボトムアップナノ構造形成技術とバイオ・ケミカルセンサへの応用[Invited]Invited oral presentation
- フィジカルセンサ/マイクロマシン・センサシステム合同研究会, Dec. 2016, Japanese, Domestic conference単一金ナノ粒子二量体を用いたアデニンの表面増強ラマン分光検出Oral presentation
- フィジカルセンサ/マイクロマシン・センサシステム合同研究会, Dec. 2016, Japanese, ，城谷修司，菅野公二，磯野吉正, Domestic conferenceSi薄膜被覆金ナノワイヤアレイ構造の光学特性評価Oral presentation
- International Symposium on Micro-Nano Science and Technology2016, Dec. 2016, English, International conferencePiezoresistance effect of VLS-synthesized core/shell-SiC nanowiresPoster presentation
- International Symposium on Micro-Nano Science and Technology2016, Dec. 2016, English, International conferenceNear Infrared Optical Absorption Property of Gold Nanoparticle Aggregates for Laser Wavelength MeasurementPoster presentation
- International Symposium on Micro-Nano Science and Technology2016, Dec. 2016, English, International conferenceHigh temperature creep forming technique of single crystal silicon thin film for 3D MEMS tactile sensorsPoster presentation
- International Symposium on Micro-Nano Science and Technology2016, Dec. 2016, English, International conferenceHighly-Sensitive and Rapid Detection of DNA bases using Surface-Enhanced Raman Spectroscopy with Gold Nanoparticle Dimer ArrayPoster presentation
- 29th International Microprocesses and Nanotechnology Conference (MNC2016), Nov. 2016, English, International conferenceSingle-Molecule Surface-Enhanced Raman Spectroscopy of 4,4'-bipyridine on Fabricated Substrates with Directionally Arrayed Gold Nanoparticle DimersOral presentation
- 29th International Microprocesses and Nanotechnology Conference (MNC2016), Nov. 2016, English, International conferenceOptimization of Gold Nanorod Array Structure on Microresonator for Resonant-Based Laser Wavelength Measurement Using Photothermal ConversionOral presentation
- 29th International Microprocesses and Nanotechnology Conference (MNC2016), Nov. 2016, English, International conferenceMechanical Characterization of VLS-Grown Core-Shell SiC Nanowires for Nanomechanical SensorsOral presentation
- 29th International Microprocesses and Nanotechnology Conference (MNC2016), Nov. 2016, English, International conferenceCharacterization Method of Relative Raman Enhancement for Surface Enhanced Raman Spectroscopy Using Gold Nanoparticle Dimer ArrayOral presentation
- 第33回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2016, Japanese, Domestic conference金ナノ粒子二量体配列を用いたDNA塩基の高感度・高速表面増強ラマン分光Oral presentation
- 第33回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2016, Japanese, Domestic conference金ナノロッド構造を用いた光熱変換によるレーザ光波長計測マイクロ振動子デバイスOral presentation
- 第33回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2016, Japanese, Domestic conference逆解析手法による単結晶Si薄膜の高温クリープ特性解明と触覚センサ開発への応用Oral presentation
- 日本機械学会 M&M2016材料力学カンファレンス, Oct. 2016, Japanese, Domestic conference逆解析による単結晶Si薄膜の三次元高温クリープ成形加工技術の確立Oral presentation
- 第33回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2016, Japanese, Domestic conferenceVLSボトムアップ成長Core/Shell-SiCナノワイヤのMEMS援用ピエゾ抵抗特性評価Oral presentation
- Pacific Rim Meeting on Electrochemical and Solid-state Science 2016 (PRiME2016), Oct. 2016, English, International conferenceSingle Molecule SERS with Directionally Arrayed Gold Nanoparticle Dimers on Substrate[Invited]Invited oral presentation
- マルチスケール材料力学シンポジウム, May 2016, Japanese, Domestic conference逆解析手法による単結晶シリコン薄膜の高温クリープ三次元成形加工技術の確立Poster presentation
- マルチスケール材料力学シンポジウム, May 2016, Japanese, Domestic conference3C-SiCNWのMEMS援用Elastic Strain Engineering研究 －ピエゾ抵抗効果の実験解明Oral presentation
- The 11th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems (IEEE-NEMS2016), Apr. 2016, English, International conferencePlasmonic Nanostructure based on Self-Assembled Gold Nanoparticles for Highly Sensitive Surface-Enhanced Raman Spectroscopy[Invited]Invited oral presentation
- The 11th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems (IEEE-NEMS 2016), Apr. 2016, English, International conferenceFabrication and Characterization of CNT Forest Integrated Micromechanical Resonator for Rarefied Gas SensorOral presentation
- The 11th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems (IEEE-NEMS 2016), Apr. 2016, English, International conferenceCrystal Orientation Dependence of Piezoresistivity for VLS-Grown Single Crystal Silicon NanowiresOral presentation
- 28th International Microprocesses and Nanotechnology Conference (MNC2015), Nov. 2015, English, International conferenceGold Nanoparticle Synthesis Using High-Speed Pulsed Mixing Microfluidic DevicePoster presentation
- 第32回「センサ・マイクロマシン と応用システム」シンポジウム, Oct. 2015, Japanese, Domestic conference金ナノ粒子二量体配列を用いた表面増強ラマン分光におけるラマン増強度評価法Oral presentation
- 第32回「センサ・マイクロマシン と応用システム」シンポジウム, Oct. 2015, Japanese, Domestic conference金ナノ粒子二量体配列を用いたDNA塩基の表面増強ラマン分光Poster presentation
- 第32回「センサ・マイクロマシン と応用システム」シンポジウム, Oct. 2015, Japanese, Domestic conference金ナノ粒子二量体配列における表面増強ラマン分光1分子検出特性Oral presentation
- 第32回「センサ・マイクロマシン と応用システム」シンポジウム, Oct. 2015, Japanese, Domestic conference金ナノ粒子直線状配列を用いた表面増強ラマン分光の特性評価Oral presentation
- 第32回「センサ・マイクロマシン と応用システム」シンポジウム, Oct. 2015, Japanese, Domestic conferenceVLS成長シリコンナノワイヤの歪み誘起電気伝導特性の結晶方位依存性Oral presentation
- International Conference on Advanced Technology in Experimental Mechanics 2015 (ATEM'15), Oct. 2015, English, International conferenceEvaluation of Piezoresistivity for VLS-Grown Silicon NanowiresUnder Enormous Elastic StrainOral presentation
- 平成27年度電気学会マイクロマシン・センサシステム部門総合研究会, Jul. 2015, Japanese, Domestic conference直線状金ナノ粒子配列の表面増強ラマン分光特性Oral presentation
- 27th International Microprocesses and Nanotechnology Conference (MNC2014), Nov. 2014, English, Fukuoka, Japan, International conferenceSurface-Enhanced Raman Spectroscopy Analysis Using Micro/Nanofluidic Devices with Gold Nanoparticle-Embedded NanochannelsOral presentation
- 27th International Microprocesses and Nanotechnology Conference (MNC2014), Nov. 2014, English, Fukuoka, Japan, International conferenceHighly-sensitive Surface-Enhanced Raman Spectroscopy with Directionally-Arrayed Gold Nanoparticle DimersPoster presentation
- 第31回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2014, Japanese, Domestic conference半導体ナノワイヤ物性評価のためのMEMS-Based Strain EngineeringPoster presentation
- 第31回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2014, Japanese, Domestic conference金粒子配列ナノ流路を用いた表面増強ラマン分光分析デバイスOral presentation
- 第31回「センサ・マイクロマシンと応用システム」シンポジウム, Oct. 2014, Japanese, Domestic conference金ナノ粒子二量体の規則的配列構造による高感度表面増強ラマン分光Oral presentation
- 日本機械学会2014年度年次大会, Sep. 2014, Japanese, Domestic conferenceMEMS デバイスによる多層カーボンナノチューブの層間すべり変形機構の解明Oral presentation
- 2014 International Symposium of Materials on Regenerative Medicine (2014 ISOMRM), Aug. 2014, English, Tao-Yuan, Taiwan, International conferenceSurface-Enhanced Raman Spectroscopy for Molecular Trace Analysis using Directionally-Arranged Gold Nanoparticles[Invited]Invited oral presentation
- 平成26年度電気学会マイクロマシン・センサシステム部門総合研究会, May 2014, Japanese, 東京大学，東京, Domestic conference一方向に配列した金ナノ粒子二量体構造の表面増強ラマン分光特性評価Oral presentation
- 第30回「センサ・マイクロマシンと応用システム」シンポジウム, Nov. 2013, Japanese, 仙台, Domestic conference表面増強ラマン分光法のための金粒子配列ナノチャンネルの作製Poster presentation
- 応用物理学会 関西支部第2回講演会, Oct. 2013, Japanese, 奈良, Domestic conferenceDevelopment of MWCNT Embedded Micromechanical Resonator Working as rarefied Gas SensorPoster presentation
- 日本機械学会 2013年度年次大会, Sep. 2013, Japanese, 岡山, Domestic conference多段 ICP-RIEプロセスを用いた架橋構造Siナノワイヤの加工Oral presentation
- 日本機械学会 2013年度年次大会, Sep. 2013, Japanese, 岡山, Domestic conferenceビオチン修飾1本鎖DNAを用いた単層カーボンナノチューブのギャップ電極への孤立アセンブルOral presentation
- 2013 JSAP-MRS Joint Symposia, Sep. 2013, English, Kyoto, International conferenceMWCNT-Embedded MEMS Resonator Fabricated by Bio-MEMS Compatible Process for Rarefied Gas SensingOral presentation
- 電子情報通信学会 ソサイエティ大会, Sep. 2013, Japanese, 福岡, Domestic conferenceAtomic MEMSのための新規なアルカリ金属蒸気セル作製手法Oral presentation
- 日本機械学会 2013年度年次大会, Sep. 2013, Japanese, 岡山, Domestic conference(100)及び(110)単結晶シリコンにおける引張強度の結晶方位依存性Oral presentation
- 日本機械学会 Dynamics and Design Conference 2013 (第13回「運動と振動の制御」シンポジウム), Aug. 2013, Japanese, 福岡, Domestic conference3軸加速度センサのマトリックス感度校正における取付角度誤差の影響評価Oral presentation
- ASME 2013 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems (InterPACK2013), Jul. 2013, English, Burlingame, USA, International conferenceFractography Analysis of Tensile Tested (110) Silicon Prepared by Different Surface Morphology and Crystal OrientationsOral presentation
- ASME 2013 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems (InterPACK2013), Apr. 2013, English, Berlin, Germany, International conferenceNovel process optimization approach for DMD-based grayscale 3D microstructuring photolithographyOral presentation
- The Society of Powder Technilogy, Japan
- The Japan Society of Mechanical Engineers
- Japan Institute of Electronics Packaging
- The Institute of Electrical Engineers of Japan
- IEEE(The Institute of Electrical and Electronics Engineers)
- 粉体工学会
- (社)日本機械学会
- エレクトロニクス実装学会
- 電気学会
- IEEE
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Apr. 2019 - Mar. 2022, CoinvestigatorMicro/Nano Fusion Process based Nanopore Sensing Device for Optical and Electrical Combined Detection
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Kobe University, Apr. 2018 - Mar. 2021, Principal investigatorNext generation DNA sequencing using surface-enhanced Raman spectroscopy本申請課題では，従来のナノポアなど電気的検出法による次世代DNAシーケンシング技術より高い信頼性を有する新規な技術として，分子識別能力に優れた表面増強ラマン分光（SERS：Surface Enhanced Raman Spectroscopy）によるDNAシーケンシングを提案し，その基盤技術の確立を目的としている。この研究により，メチル化など異常修飾を含めた塩基配列を識別可能なDNAシーケンシング技術が期待される。平成30年度では以下の項目を明らかにすることを目的としてSERSおよび電気的手法によるDNAオリゴマー検出実験を行った。 (1)DNA断片における1塩基検出感度・1塩基空間分解能の実現と諸特性・現象の理解 単一金ナノ粒子二量体を用いてDNAオリゴマーのSERS計測を行った。単一の金ナノ粒子二量体のナノギャップ部分は単一のDNAオリゴマーのみ侵入可能な空間であり，本実験でDNAオリゴマー内容物のラマンピークが観測されることで単一DNAオリゴマーの検出が確認できる。CCCCACCCのDNAオリゴマー内にある種類の塩基（アデニン）が1つのみ含まれる配列にてSERS計測を行った結果，アデニンの明確なラマンピークが検出された。これにより，DNAオリゴマー内の1分子塩基感度の検出・同定が可能であることを実証した。 (2)巨大電磁場増強場におけるDNA断片挙動の理解とマニピュレーション技術の確立 トップダウン加工でナノギャップ電極を形成し，ナノギャップ（巨大電磁場増強場）におけるDNA断片の挙動を電気的計測により調べた。レーザ照射による電磁場増強によって大きな電場勾配が発生するためDNAオリゴマーに誘電泳動力が働くと考えられる。これまでにレーザ照射することでナノギャップ間に電流シグナルが得られた。この結果によりレーザ照射により分子がナノギャップに引き寄せられていることが考えられる。
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Kobe University, Apr. 2018 - Mar. 2021, CoinvestigatorEffect of Surface Potential on Piezoresistivity for Semi-conductive Nanowires
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Kyoto University, Apr. 2016 - Mar. 2019, CoinvestigatorHighly sensitive detection of single molecule was successfully demonstrated which is based on surface enhanced Raman scattering principle using gold nanoparticle (GNP) dimer. The dimer is fabricated by sacrificial DNA origami technology using 30 nm GNPs. The detection and identification of single DNA oligomer and single Adenine base was successfully achieved using single GNP dimer. Immobilization of a DNA origami nanostructure at a specific position of a substrate were successfully demonstrated. Using He ion beam technique, a Graphene nano pore with diameter of 1.5 to 2 nm, optimumized size for DNA base detection, was fabricated with good reproducibility. It was demonstrated that the DNA sensing based on ion current measurement principle was succeeded using the fabricated Graphene nano pore. Through the project, fundamental technology for nano pore sensing device based on opto-electro detection principle was established.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Kobe University, Oct. 2015 - Mar. 2018, Principal investigatorThe purpose of this project was to develop the analytical method for multi-component identification of molecules based on surface-enhanced Raman spectroscopy using a gold nanoparticle dimer with single molecule sensitivity. Due to the Raman enhancing hotspot with 1 nm nanogap in the single dimer, for the first time, the single oligomer detection and analysis was demonstrated. The dimer identified the several bases and backbone components of the single DNA oligomer. The dynamics of the single oligomer could be analyzed. The oligomer was trapped and stayed at the nanogap hotspot, and fluctuated with rotation.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Kobe University, Apr. 2015 - Mar. 2018, Coinvestigator3C-SiCNWs are one of promising piezoresistive elements used in harsh environmental MEMS/NEMS applications, because of its high dielectric breakdown strength and excellent temperature/chemical stabilities. Especially, 3C-SiCNW wrapped by SiO2 shell is directly effective for fabrication of vertical structure FETs and FET-based mechanical sensors. This research clarified mechanical properties and piezoresistivity of 3C-SiCNWs wrapped with SiO2 (core/shell silicon carbide nanowires: C/S-SiCNWs) for harsh environmental MEMS/NEMS applications, using the MEMS-based nanotensile testing device. The tensile strengths for 3C-SiCNWs without SiO2 shell, and C/S-SiCNWs showed huge values of 22.4 GPa and 7.3 GPa on average, respectively. The gauge factor of the 3C-SiCNW without SiO2 shell showed -17.2 at 0.022 ε. Thus, the C/S-SiCNW has behaved as an n-type semiconductor, and it is useful as structural materials and piezoresistive elements in harsh environmental MEMS.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Apr. 2012 - Mar. 2015, Principal investigatorA gold particle dimer shows huge electromagnetic enhancement when particle connection direction is matched to polarization direction of incident light. In this study the dimers were arrayed by the nanotrench-guided self-assembly for generating huge total Raman enhancement. The fabricated structures were characterized for Surface-Enhanced Raman Spectroscopy (SERS) depending on polarization angle to particle connection direction. The Raman intensity increased with decreasing the angle. Since electromagnetic interaction between dimers has large effect on Raman enhancement, the distance between dimers were optimized. The distance of 100 nm between dimers showed the highest Raman intensity. The optimized structure detected 4,4'-bipyridine molecules at the concentration of 10 pM. The detection for 100 nM solution was possible at the integration time of 0.2 s. This developed SERS substrate is expected to be applied to various trace analysis with high sensitivity and short detection time.
- 科学技術振興機構, 研究成果最適展開支援プログラム フィージビリティスタディステージ 探索タイプ, 2015, Principal investigatorA-STEP「金ナノ粒子二量体配列基板を用いた高感度・高信頼性表面増強ラマン分光技術の開発」Competitive research funding
- 研究成果最適展開支援プログラム フィージビリティスタディステージ 探索タイプ, 2014, Principal investigatorA-STEP「金ナノ粒子二量体配列基板を用いた高感度・高信頼性表面増強ラマン分光技術の開発」Competitive research funding
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B), Grant-in-Aid for Young Scientists (B), Kyoto University, 2010 - 2011, Principal investigatorI developed the highly-precise arrangement technique of nanoparticles, which can control the nanoscale gap between two particles from 10 to 60 nm, by Template-Assisted Self-Assembly using the nanoscale template trenches. In this study, by solving the problem of electrostatic repulsive force between particles by the addition of electrolyte, I achieved high assembly yield of around 90% for the gap-controllable nanoparticles dimer.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B), Grant-in-Aid for Young Scientists (B), Kyoto University, 2006 - 2007, Principal investigatorマイクロチップを用いた脈動混合による単分散金ナノ粒子創製金ナノ粒子の局所プラズモン共鳴(LPR)や表面増強ラマン散乱(SERS)を用いた化学分析の高感度化を実現するために,最も大きな電場増強を示す粒子径60nmで粒子径分布の小さな金ナノ粒子を還元法により作製することを目的とした.そのため,マイクロポンプと混合用マイクロ流路を用いた脈動混合を2液に適用した.この手法により迅速な2液混合を行い,小さな粒子径分布の金ナノ粒子を作製する.研究成果を以下に示す. (1)脈動混合法の混合速度評価: 蛍光顕微鏡を用いて蛍光色素と純水の2液が混合する様子を観察し,混合速度を計算した.その結果,最短で95msecの混合が可能であり,混合速度をマイクロポンプの切替周波数により制御できることがわかった. (2)ポリマーマイクロ流路の設計・製作: ポリマー製の最適な混合流路形状を設計するために,流路内圧による流路変形を考慮することができる新しい電気等価回路解析モデルを構築した.このモデルにより,流路形状による流量や流れの応答性を正確に解析することができる. (3)脈動混合を用いた金ナノ粒子作製と粒子生成メカニズムの考察: 脈動混合により混合速度を制御し金ナノ粒子を作製した.(1)での混合速度と生成した粒子の粒子径・粒子径分布の関係から生成メカニズムについて考察を行った. (4)化学分析への応用の検討: LSPもしくはSERSを用いた化学分析に応用するために,金ナノ粒子の電場増強と消失スペクトルを有限差分領域法(FDTD)を用いて計算し,最適な構造を導出した.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B), Grant-in-Aid for Young Scientists (B), Kyoto University, 2004 - 2005, Principal investigator異種材料微粒子アセンブル技術による卓上型シンクロトロンのための軟X線源の開発本研究では新規な微粒子のアセンブル技術を用いて卓上型シンクロトロン用の軟X線源構造を作製することを目的とした.本年度は1)理論計算による軟X線源構造の設計と2)軟X線源の中の微細構造を実現する粒子アセンブル技術の開発を行った. 1)理論計算による軟X線源構造の設計 理論計算によって軟X線放射に必要な膜厚と間隔を求めることができる.その際に,膜厚と間隔の誤差が放射強度に与える影響を計算した.その結果,使用する軟X線放射の角度によって誤差の影響が変わった.41mradの放射角度を使用する場合,寸法誤差による放射強度の減少を10%に抑えるためには約0.2μmの寸法誤差まで許容することが明らかになった. 2)粒子アセンブル技術 軟X線源実現のために膜厚の間隔を上記で求めた許容誤差範囲に抑えることが重要である.そのため,膜厚間に支柱を設けるための微粒子アセンブル技術を開発した.微粒子として直径500nmのポリスチレン粒子を用いた.支柱となる微粒子を所望の形状にパターン化するために,a)微細溝を有するテンプレート基板へのセルフアセンブル技術とb)アセンブルによって形成したパターンのターゲット基板への転写技術を実現した.a)ではテンプレート基板上のコロイド溶液を乾燥させ,メニスカスの後退速度を制御することで,微細溝への高収率なアセンブルが可能となった.b)では自己組織化膜を用いて基板の撥水性を変えることで,粒子と基板間の付着力を制御した.これらの結果により所望の粒子パターンを得ることができ,軟X線源のための支柱構造が実現される.