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A Micro platform for micro gas sensor consisted of micro heater, insulator, and sensing electrode on 2 uNthick SiN x membrane.Three types of micro platforms were designed and fabricated with membrane sizes. Total size of micro platform was 2.6 mm by 2.6 mm.Measured power consumptions were 28 mW, 28 mW, and 32.5 mW for Type 1, Type 2, and Type 3. At this moment, temperatures ofmembranes on the platforms were 295 \C, 297 \C, and 296 \C, respectively. Fabricated micro platform considered appropriate to applyfor low power consumption micro gas sensor. Micro gas sensors were prepared by the sequence that SnO 2 nanopowder pastes weredropped on membrane of Type 1 platforms, dried in oven, heat-treated with micro heaters in platforms. One of the micro gas sensors wastested for gas response to 1157 ppm, 578 ppm, and 231 ppm of methane and 1.68 ppm, 0.84 ppm, and 0.42 ppm of NO 2 . Keywords : MEMS, Micro Gas Sensor, Micro Platform, Low Power Consumption ² y > } a B A Ž : × > A ² ×b & @ ³ 2 : t E Þ PD A ² 3 2 & A Ž Þ × jI a A P 3 Ž Þ × j i I D ( ?8 «L uS i n A ² ENd 3 ? Þ t ENd D ( 3 u ýy o c± × E a8 Þ × O O ¬7 s O & @ 2 ‰ ³ 2 Þ × oI >N ‹ × n7y nI ³ : t u Ý 3 m × a uS ( þ × > > Þ c a i .&.4 •7I i M7 ~x8 > Þ Þ q Þ Ý x ™ A > A ² 3X Þ Ý$ c m O A FI Ž : » i O 3 \ ¯ CI u ýd 3 * ; NO D y A R o = ý ' ? Þ E ? a ƒ > ; 8 CI u ý™ i ³‘ ý ? Þ E u ý C 7 O Ð O ³5 ýC E ?, Ý a › > hN 3 a ƒ CI u ýd i ENy O8 ¯ eI ýX a ƒ CI u ýd 3 « ;I · X • A —Q Þ EX a ƒ >S i E ³ A ² ×.&.4 •8O i Þ E > A ² ýI a CI u ý O O ¬8‘ Þ Š CI u ý O O ¬D CI u ýd AK > : × × :y n — O O ¬o , a ( 3  Þ E ` ?8‘ Ž Þ O5 t > A ²Dx ?8 K Þ Ý$ c‘ ; CI u ý O O ¬ A ENd 3 ? Þ E CI u ý > A ² ýX Þ Š k —/0

Using mixed SnO2 nanoparticles with 1 wt.% MWCNTs sensing materials, NO2, NH3, and xylene gas sensors were fabricated on micro-platforms. A micro-platform consists of micro-sensing electrode and micro-heater on 2 μm thick SiNx membrane. The fabricated gas sensors were characterized to NO2, NH3, and xylene gases, respectively, as a function of concentration at 300 °C and temperature from 180 °C to 380 °C at constant concentration. The measured highest sensitivities for the NO2, NH3, and xylene were 1.06 at 1.2 ppm and 220 °C, 0.19 at 60 ppm, and 220 °C, and 0.15 at 3.6 ppm and 220 °C, respectively. So, it was found that 220 °C was the optimum temperature to have the best sensitivities. From these results, mixed SnO2 nanoparticles with 1 wt.% MWCNTs showed good sensitivity and selectivity at low power operation below 30 mW. Fabricated micro-gas sensors could be used for ubiquitous sensor network applications to monitor environmental pollutants in the air.

In this study, a InGaAs/InP passive unit pixel with an optical-sensitivity-improved heterojunction phototransistor (HPT) for array imaging applications has been designed and characterized for low-light signal detection considering light-dependent shunt resistance. Using the proposed devices, a 1×256 highly sensitive linear array chip with suitable shunt resistance has been fabricated and characterized. The designed passive unit pixel consists of one photodetector and one select transistor with a collector–base terminal tied configuration for a wide dynamic range. We also present epitaxial structures and an equivalent model to optimize optical gain and shunt resistance characteristics. The device operation mechanism and experimental results are discussed. The experimental results show that our device has an optical sensitivity of 118 A/W, which is significantly higher than that of a conventional PIN photodetector with the same light-absorbing area. This high sensitivity originates from the optical gain-enhanced device structure. A typical optical gain is approximately 236, which means HPTs are 236-fold more sensitive than PIN photodetectors. The proposed HPT also has tens of kΩ shunt resistance with high optical sensitivity under low illumination, which is sufficient for effective signal conversion through a transimpedance amplifier circuit.

An InGaAs/InP heterojunction phototransistor (HPT) 1×128 one dimensional array chip with an improved optical sensitivity and shunt resistance has been designed and characterized for the detection of a low light signal intensity. We also present epitaxial structures and an equivalent model for optimizing the optical gain and shunt resistance characteristics. The device operation mechanism and experimental results are discussed. The experimental results show that our device has an optical sensitivity of 46 A/W, which is significantly higher than that of a conventional PIN photodetector with the same light absorbing area. This high sensitivity originates from the optical gain-enhanced device structure. The typical optical gain is approximately 94, indicating that HPTs are 94 times more sensitive than PIN photodetectors. The proposed HPT also has over 100–200 of kΩ shunt resistance and a high optical sensitivity under a low illumination condition, which is sufficient for effective signal conversion through a trans-impedance amplifier circuit. In addition, we also discuss a high-power optical-stress-induced dark current reduction effect that is similar to a thermal-annealing-induced dark current reduction effect. of An optical-stress-induced dark current reduction of approximately 1 order is observed in our experiments.

Various types of piezoelectrically driven microtransducers which have a similar physical dimension, i.e., microcantilever, microdiaphragm and microbridge, were fabricated by micro electromechanical system (MEMS) technique and are compared on the mass sensing behavior. The diol based sol-gel derived Pb(Zr0.52,Ti0.48)O3 (PZT) thin film capacitors were integrated for the piezoelectric actuation. We have used the resonant frequency change of microtransducer upon mass increase as a sensing mechanism. The resonant frequency of the microtransducer was measured by analysis of electrical signals from microtransducer such as impedance, capacitance, phase and dielectric loss. The fundamental resonant frequencies of the microcantilever, microbridge and microdiaphragm with similar dimension (∼300 μm) were about 26 kHz, 260 kHz and 290 kHz, respectively. The mass sensitivities of bare microtransducers were measured by metallic thin film deposition and analysis of spectral responses from microtransducers. When ...

An integrated microammonia analysis system (IMAAS) with microreactor and in-plane ( x -axis) type optical source and optical detector with ease and precise optical alignment method using microchannels for optical fiber guide by silicon deep RIE process based on the Berthelot reaction was newly proposed and investigated. It is not necessary to do difficult and complex optical alignment process for ammonia analysis than the case of using out-of-plane ( z -axis) type optical detector perpendicular to microfluidic devices. The proposed IMAAS with the size of 5 cm × 5 cm and thickness of 1 mm was fabricated using typical and simple MEMS processes. IMAAS was packaged with inlet and outlet tube, and optical fiber connected with in-plane type optical source and optical detector using UV epoxy bonding. Reaction rates from ammonia of the concentration of 16.5 ppm to indophenols at IMAAS were remarkably increased with temperatures from 308 to 318 K on hot plate as a heater. In case of reaction temperature of 318 K, complete reaction time was less than 1 min. Reaction rates were increased with ammonia concentrations from 4.1 to 33.0 ppm at the temperatures of 308, 313 and 318 K. In order to remarkably decrease total analysis system, thermoelectric heater of 2 cm × 2 cm was used as a heater. In case of using thermoelectric heater at the temperature of 308 K and the ammonia concentration of 2 ppm, the complete reaction time of indophenol in IMAAS was in the range of 100–150 s. From these results, IMAAS on thermoelectric heater has advantage for small size and local heating of reaction region in IMAAS than the case of using hot plate heater. Fabricated IMAAS were reproducible and suitable for the determination of ammonia concentrations. For the future works, it was thought these microsystems could be used for other microreactions for versatile species analyses as well as detections for N-containing organic species.

Piezoelectrically driven microbridge gas sensors have been fabricated by MEMS process. We have used the resonant frequency change of the microbridge transducer upon mass increase. The sol-gel derived Pb(Zr0.52,Ti0.48)O3 (PZT) film capacitor as an actuating part was integrated into the thin SiN x bridge structure. The resonant frequency of the microbridge was in the range of 250 kHz to 260 kHz. The microbridge exhibited a mass sensitivity and gravimetric sensitivity factor of ca. 7.27 pg/Hz and 345 cm 2 /g, respectively. With the PMMA polymer sensing layer, the microbridge showed the gas sensitivity of 1.67 ppm/Hz for ethanol vapor.

A low actuation voltage and no contact stiction are important factors in applying micro-electro-mechanical-system (MEMS) RF switches to mobile communication devices. Conventional electrostatic RF MEMS switches require several tens of voltages for actuation. In this paper we propose a piezoelectric actuated seesaw (PAS) RF MEMS switch which adopts Pb(Zr, Ti)O3 (PZT) actuators and seesaw cantilevers to meet the above requirements. The fundamental structures of PAS RF MEMS switches were designed, optimized, and fabricated. Through the developed process of PAS single pole double through (SPDT), RF MEMS switches were successfully fabricated on a 4'' wafer and they showed good electrical properties. The driving voltage was less than 5 volts and the insertion loss was −0.5dB and the isolation was −35dB at 5GHz. The maximum switching speed was about 5kHz. Thus these RF MEMS switches can be applicable to mobile communication devices or wireless multi-media devices at a frequency lower than 6GHz.

A capacitive absolute pressure sensor was fabricated using a large deflected diaphragm with a sealed vacuum cavity formed by removing handling silicon wafer and oxide layers from a SOI wafer after eutectic bonding of a silicon wafer to the SOI wafer. The deflected displacements of the diaphragm formed by the vacuum cavity in the fabricated sensor were similar to simulation results. Initial capacitance values were about 2.18pF and 3.65pF under normal atmosphere, where the thicknesses of the diaphragm used to fabricate the vacuum cavity were 20 µm and 30 µm, respectively. Also, it was confirmed that the differences of capacitance value from 1000hPa to 5hPa were about 2.57pF and 5.35pF, respectively.

We present the fabrication process and characteristics of a 3-axes flexible tactile sensor available for normal and shear mode fabricated using Si micromachining and packaging technologies. The fabrication processes for the 3 axes flexible tactile sensor were classified in the fabrication of sensor chips and their packaging on the flexible PCB. The variation rate of resistance was about 2.1%/N and 0.5%/N in applying normal and shear force, respectively. Because this tactile sensor can measure the variations of resistance of the semiconductor strain gauge for normal and shear force, it can be used to sense touch, pressure, hardness, and slip.

We have fabricated piezoelectric microcantilever transducer for a miniaturized gas sensor, to detect environmental gas molecules, i.e., volatile organic compound (VOC). The microcantilever consist of Pb(Zr, Ti)O 3 (PZT) capacitors and SiNx layer as an actuating and a supporting layer respectively. The fundamental resonant frequency of microcantilever was in the range of 17∼29 kHz. To measure the gas sensitivity, the microcantilever surface was coated with polymethylmetacrylate (PMMA), which is known to have sensibility for primary alcohols. The resonant frequency shift of the microcantilever was measured by complex impedance analysis, which only uses electrical signal output from the microcantilever. As the vapor concentration of the alcohol (ethanol or methanol) increased, the resonant frequency of microcantilever was linearly shifted toward the lower frequency range. The gas sensitivity of microcantilever was 0.03 Hz/ppm for methanol vapor.

Recently, many researchers have been attempted to reduce the power consumption in the sensor system and to increase the sensitivity for toxic gases. Most metal oxide sensing films are deposited on an alumina substrate which is easy process but needs high power consumption. Moreover, thin film sensor deposited on the Si substrate shows low sensitivity. Accordingly, this study investigated the fabrication of thick film gas sensors based on tin oxide on a Si substrate. Two heater shapes using a micro electro mechanical system (MEMS) are designed and simulated, and their gas response characteristics to test gases were examined. The sensing materials are SnO2 mixed with Al2O3, and test gases are CH2Cl2, CH3CN as simulant chemical warfare agents. Consequently, high sensitivity is acquired by using a thick sensing film and low power consumption is achieved by using MEMS technology.

Design and fabrication of micro mixing cells and detection cells were investigated. Glass micro mixing cells with island structures among channels were fabricated using sand blaster methods. Depth and width of mixing channel were 200 ㎛ and 180 ㎛ and island size was 90 ㎛ by 90 ㎛. Two 45° mirrors surfaces faced on each other in one detection cell which were fabricated by silicon anisotropic etching using 20% TMAH (Tetramethylammonium hydroxide) solution with 20% or 30% IPA (iso propyl alcohol) at 80°C, respectively. Up side glass wafer for mixing cell and down side silicon wafer for detection cell were bonded using anodic bonding method at 350ı, -600 V and 300 N. Synthetic indophenol was injected at inlet and moved to the detection cell through the mixing channel. HeNe laser of 632.8 nm was focused on one side of a 45° mirror, and passed through indophenol solution until the other side of a 45° mirror. The light of 632.8 nm was absorbed in indophenol solution between two 45° mirrors at detection cell. By the Beer-Lambert’s law, indophenol concentration could be calculated from the measured result of the absorbance.

Fabrication processes of PZT micro cantilevers using isotropic silicon dry etching process by XeF 2 gas of front side were newly proposed and investigated. The purpose of study was to compare the proposed processes using only front side for release process of PZT micro cantilevers with conventional processes using bulk silicon micromachining of backside, and so on. In case of the proposed method, it was not necessary to use double side aligner, and wet chemical solutions and other protection jigs for silicon bulk micromachining of backside. During release process using isotropic silicon dry etching by XeF 2 gas, patterned 1.2 μm-thick photo-resist film layers were used for protective film on upper Pt electrode and PZT film. Degradation of properties of PZT films after release process using XeF 2 gas was not found. In case of operating at 3.9 V and 1.9 kHz of fabricated PZT micro cantilevers with 650 μm length by 100 μm width, these were actuated with resonant and vibrated up to the width of 125.9 μm. Consequently, microstructures and electromechanical properties of PZT micro cantilever by new proposed method were compatible to other conventional methods. It was thought that proposed processes were more cost effective, stable and mass productive than other reported processes.

We have fabricated high sensitive gas sensor based on piezoelectrically driven micro-diaphragm transducers. The micro-diaphragm transducer was fabricated using micro-electro-mechanical-system (MEMS) technique. The diol based sol-gel derived Pb(Zr0.52,Ti0.48)O3(PZT) film was used as a piezoelectric actuating layer. We have used the resonant frequency change of micro-diaphragm transducer upon mass increase as a sensing signal. The resonant frequency values were measured by analysis of electrical signals from the micro-diaphragm transducer. The fundamental resonant frequency of the micro-diaphragm was in the range of 250 to 360 kHz, depending on their physical boundary conditions. The mass sensitivity of bare micro-diaphragm transducer was 66.5 Hz/ng. Two polymer sensing layers such as the polymethylmethacrylate (PMMA) and polydimethylsiloxane (PDMS) films were used to estimate the gas sensing behavior of microtransducers for various vapors of organic compounds. PMMA was used to detect primary alcoh...

We have studied structural and electrical properties of one dimensionally grown single crystalline gallium nitride (GaN) nanowires (NWs) for nanoscale devices using a metal-initiated metal-organic chemical vapor deposition (MOCVD). GaN nanowires were formed via the vapor-liquid-solid (VLS) mechanism with gold, iron, or nickel as growth initiators and were found to have triangular cross-sections with widths of 15 ∼ 200 nm and lengths of 5 ∼ 20 μm. TEM confirmed that the nanowires were single crystalline and were well oriented along the [210] or [110] direction on substrate depending on the metal initiators. For electrical transport properties of un-doped GaN nanowires, the back-gated field effect transistors (FET) were also fabricated by standard e-beam lithography. In our electrical measurement, the carrier concentration and mobility were 2 ∼ 4 × 10 18 cm -3 and 60 ∼ 70 cm2/V s, respectively.

The microstructures and electrical properties of thin and thick Pb(Zr0.52, Ti0.48)O3 (52/48 PZT) films for microdevice applications with thicknesses from 480 nm to 2.3 µm on 350 nm Pt(111)/40 nm Ti/300 nm SiO2/Si 525 µm substrates fabricated by a sol–gel multicoating process were investigated. These PZT films showed dense and homogeneous surface microstructures. The crystalline structures of 480-nm-thick PZT films showed a (111) preferred orientation over (100), (200) and (110) orientations. The intensity ratios of (100) and (200) to (111) increased at PZT film thicknesses greater than 480 nm. By Auger electron spectroscopy, small-composition-variation peaks at an interval of approximately 120 nm at interfaces produced by each PZT coating process of 480 nm PZT films were found. Dielectric constants increased from 825 to 880 at 100 kHz and PZT film thicknesses from 480 nm to 2.3 µm. The Pr and Ec of 2.3-µm-thick PZT films were about 30 µC/cm2 and 58 kV/cm, respectively. The e31,f of 1-µm- and 2-µm-thick PZT films was characterized by the fabricated e31,f measurement system before and after poling.

Thermal stability and characterizations of silicon to silicon wafer bonding at low temperature using B-staged polymer, bisbenzocyclobutene (BCB), were investigated. Bare silicon to bare silicon wafer (briefly, bare to bare) and patterned silicon by chemical etching to bare silicon wafer (pattern to bare) bonding with 4 in. size were achieved by heating BCB coated wafer pairs at 230 °C. In case of bare to bare bonding, interfaces of bonded wafers were mechanically stable and strong enough to withstand a tensile force of at least 190 kg/cm2 at room temperature. Bond strength was drastically decreased over 300 °C because of decomposition of polymer. In case of pattern to bare, interfaces of bonded wafers were dense and good enough to withstand a tensile force of at least 60 kg/cm2 at room temperature. Silicon to silicon wafer bonding using BCB was suitable for fabricating and packaging of microstructures for micro-electro-mechanical system (MEMS) devices at low temperatures (

The fabrication and analysis of a cantilever microtransducer were performed for a mass-detecting device. We designed piezoelectric microcantilever arrays with various lengths and shapes to investigate their resonance properties and sensitivity. Finite element method (FEM) simulation was carried out to estimate the resonant property of the microcantilever. A multilayered piezoelectric microcantilever has been successfully fabricated using micro-electromechanical systems (MEMS) processing. The microcantilever employs a sol-gel derived Pb(Zr0.52Ti0.48)O3 (PZT) capacitor fabricated on a low-stress SiNx layer. The microcantilever showed a natural resonant frequency of 16–26 kHz. The microcantilever exhibited a mass sensitivity of 34.1 Hz/ng, which enables its application to nanobalance, i.e., to detect biomolecules or gas molecules in a nanogram regime.

The SnO2/Al2O3/Pd and SnO2/Al2O3/Nb2O5/SiO2 thick film sensors were fabricated by screen printing and dipping methods, and their sensing characteristics to CH3CN gas were investigated. The oxidation products of CH3CN on the thick film were analyzed by FT-IR using a heatable gas cell. For the SnO2/Al2O3/Pd thick film, metallic Pd played a great role as a co-catalyst for the oxidation of CH3CN. The IR results showed that the products formed by oxidation of CH3CN at 300°C on the SnO2/Al2O3/Nb2O5 thick film without SiO2 were mainly CO2, H2O, and NH3, while on the SnO2/Al2O3/Nb2O5/SiO2 thick film products such as CO2, H2O, N2O, HNO3, and HNO2 were observed. The thick film devices containing SiO2 showed high selectivity and negative sensitivity to CH3CN due to the presence of nitrogen compounds produced by oxidation of CH3CN. The optimum amount of Nb2O5 and operating temperature were 1.0 wt% and 300°C, respectively.

A piezoresistive silicon pressure sensor with bipolar on-chip signal conditioning circuits permits offset voltage, full scale span and temperature coefficient of offset voltage and full scale span to be calibrated from a trimming ion-implanted resistors. The ion-implanted resistors with temperature coefficient of 1700 ppm/°C or 4700 ppm/°C were fabricated by the same process as that used for the base and piezoresistors. The fabricated sensor exhibits a sensitivity of 40.5 mV/kPa and temperature coefficient of 46 ppm/°C at the temperature range of −10 to 70°C.

MEMS six-element array platforms (MAP) with low power consumption for micro/nano gas sensors were newly designed, fabricated and characterized. The total size of MAPs was same as 8 mm by 12mm. Five samples of MAPs were designed with ratios of SiN x membrane areas to Pt heater areas 7.14(sample 1), 10.90(sample 2), 13.63(sample 3), 16.51(sample 4), and 19.51(sample 5). Good linearity of temperatures from 300 degree C to 625 degree C with increasing input power consumptions of individual elements of MAPs was shown. Power consumptions of five samples were in the range of about 58∼62 mW at 300 degree C measured at the center of membranes of MAPs. At different applied voltages to micro heaters for all six elements of a MAP sample, they showed good temperature uniformity. It was thought that the suggested MAP could be used for portable micro/nano gas sensor arrays for detection and discrimination mixture gases, simultaneously.

In this letter, we discuss a sensor-integrated system model for metabolic syndrome prediction with workflow system. This model measures not only a cell temperature variation using invasive method but also controlling simulation for metabolic syndrome prediction. To identify the system realization, we discuss the schemes for predicting metabolic syndrome from measurement of mitochondrial activity by using high precision sensors and integrated simulation model of human energetic under high performance workflow computing environment. To predict metabolic syndrome, we built a sensor-integrated chamber that had network interface to deliver analysis results of human cells, annotation data from public hospital, and metabolic data. Using the proposed system, we showed the possibility to evaluate the functionality of human mitochondria and analyze energy metabolism.

In this paper, we discuss nano sensor-integrated system model for metabolic syndrome estimation with workflow management system. We also represent function modules which can measure the heat metabolism in cell level and analyze it to distinguish condition of cell and human system. As for the evaluation of proposed system, we composed prototype workflows that automate each step of metabolism estimation simulation experiment processes with Kepler Extension model that is useful for distributed collaborative simulation. Through the experimental results, we conclude that the proposed system enhanced distributed workflow execution performance according to the cell metabolism simulation model.

To measure the thickness of the subcutaneous adipose tissue layer, a novel non-invasive optical measurement system (λ=1300 nm) is introduced. Animal and human subjects are used for the experiments. The results of human subjects are compared with the data of ultrasound device measurements, and a high correlation (r=0.94 for n=11) is observed. There are two modes in the corresponding signals measured by the optical system, which can be explained by two-layered and three-layered tissue models. If the target tissue is thinner than the critical thickness, detected data using diffuse reflectance method follow the three-layered tissue model, so the data increase as the thickness increases. On the other hand, if the target tissue is thicker than the critical thickness, the data follow the two-layered tissue model, so they decrease as the thickness increases.

Background/purpose: It is important to measure the thickness of hypodermis, including the subcutaneous fat layer in several fields such as global assessment of nutritional status and monitoring of dietary manipulation. It also provides useful information concerning the amount of peripheral adipose tissue and can be used as an index of obesity. Methods: To measure the thickness of the subcutaneous adipose tissue layer, the optical properties of tissue components, several lipids and animal tissue samples in vitro were measured over the wavelength range from 1000 to 1700 nm, using the transmittance measurement system and the diffuse reflectance measurement system. A wavelength range for the thickness measurements was selected from the experimental result. The corresponding signal according to the changes of adipose tissue thickness was measured. Results: Experimental data measured by the non-invasive measurement system were compared with the actual thickness of animal samples, and the results could be explained by the three-layered tissue model. The result showed high correlation to the thickness changes (R2 = 0.9954). Conclusions: The experimental result implies positive possibility for the development of a system to measure the thickness of subcutaneous adipose tissue using near infrared in vivo.

We present fabrication of flexible tactile sensing module with NiCr strain gauge as sensing element and interconnecter for signal treatment by polymer MEMS (micro electro mechanical system) technologies using polyimide materials. The tactile sensor array is composed of 16 times 16 sensing elements with 2 mm times 2 mm cell size and its overall size is 4 cm times 5 cm. Both the tactile sensor array and interconnecter are placed in the sensing module during the fabrication process. The fabricated tactile sensing module is measured continuously in the normal force range of 0~1 N with tactile sensor evaluation system. The variation of resistance is relatively increased linearly in the range of 0~0.6 N and saturated after 0.6 N. The variation rate of resistance is approximately 3%/N in the linear range. In addition, the flexibility of the sensing module is adequate to be placed on any curved surface like cylinder because the matrix consists of polymer and metal thin film.

We present the fabrication process and the characteristics of a flexible tactile sensor by silicon micromachining, polymer processing and packaging technologies. The fabrication process for the tactile sensor was composed of in the fabrication of sensor chips and their packaging on the flexible printed circuit board (FPCB). The variation rate of resistance was about 4.6%/N when normal force was applied. This sensor can be used to sense touch, pressure, and slip because the signals are is are determined by the variations of resistance of the metal strain gauge for normal and shear force in tactile sensor.

Integrated micro ammonia analysis systems (IMAAS) with micro reactor and in-plane type optical detector using Berthelot reaction and micro fluidic devices were newly proposed and investigated. IMAAS with the size of 5 cm by 5 cm and thickness of 1 mm were fabricated using MEMS processes. IMAAS were packaged with inlet and outlet tube, and optical fiber connected with in-plane type optical source and optical detector using UV epoxy bonding. Reaction rates from ammonia to indophenols at IMAAS were increased with temperatures. In case of reaction temperature of 318 K, reaction time was less than 1 min. From these results, fabricated IMAAS were reproducible and suitable for ammonia analysis. For the future works, it was thought these micro systems could be used for other micro reactions for versatile species analyses as well as detections for N-containing organic species including ammonia.

The wafer-level packaging of an electrostatic Si microgripper was investigated. It is important to ensure safe handling and freedom from damage during fabrication and assembly of micro devices. Some reliability problems have occurred during packaging or handling of the microgripper, regardless of actuation principles. After pre-release of the sacrificial layer, a new wafer-level packaging was processed by anodic bonding between a glass wafer with through-holes and a Si wafer device. A laser dicing has been performed before wire bonding for freedom from damage during both dicing and packaging processes. After the laser dicing, post-releasing has been done. The diced chips were actuated by applied voltage from 0 V/sub dc/ to 15 V/sub dc/. The jaws of the fabricated microgripper have been actuated from 0 /spl mu/m to 25 /spl mu/m.

In this paper we present a micromirror fabrication technique without using silicon-on-insulator (SOI) wafers. Torsional electrostatic micromirrors have been fabricated using a combination of chemical mechanical polishing (CMP) process and anodic bonding. The size of fabricated silicon mirror plate was 610x400 μm 2 and 20 μm thick. The steering electrodes have been fabricated in the dry etched trench on the glass wafer by electroplating process and CMP processing without damage of electrodes during anodic bonding process. The surface roughness of polished silicon micromirror(Ra) was 3.19nm. The single crystal silicon mirrors are electrostatically actuated with parallel bottom electrodes placed 8 μm below the mirror plate, and they could be stably operated in a ±1.1°. The pull-in voltage has been measured as 520 V. The resonant frequency of the fabricated torsion mirror was 47.3 kHz.

The authors add a missing reference to the article published in phys. stat. sol. (b) 241, 2775 (2004), referring to one of their own earlier papers in Nano Lett. 3, 1063 (2003). (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

【Properties of Ag thick films fabricated by using low temperature curable silver pastes were investigated. Ag pastes were consisted of polymer resins and silver powders. Ag pastes were used for conductive or fixing materials between board and various electrical and electronic devices. Low temperature curable Ag pastes have some advantages over high temperature curable types. In cases of chip mounting, soldering properties were required for screen printed Ag thick films. In this study, four types of Ag pastes were fabricated with different compositions. Screen printed Ag thick films on alumina substrates were fabricated at various curing temperatures and times. Thickness, resistivity, adhesive strength and solderability of fabricated Ag thick films were characterized. Finally, Ag thick films produced using Ag pastes, sample A and B, cured at $150^{\circ}C$ for longer than 6 h and $180^{\circ}C$ for longer than 2 h, and $150^{\circ}C$ for longer than 1 h and $180^{\circ}C$ for 1 h, respectively, showed low resistivities of $10^{-4}$ $∼10^{-5}$ Ωcm and good adhesive strength of 1∼5 Mpa. Soldering properties of those Ag thick films with curing temperatures at solder of 62Sn/36Pb/3Ag were also investigated.】