A thin film bulk acoustic wave resonator (TBAR) has been fabricated using a ZnO piezoelectric thin film sandwiched by top and bottom electrodes on a SiO₂ diaphragm by MEMS techniques. The elctrode/ZnO/electrode/SiO₂ structure can be designed to cancel a temperature coefficient of frequency constant (TCF) by optimizing the ZnO/SiO₂ thickness ratio, because the TCF of ZnO is negative, and that of SiO₂ is positive. The ZnO thin film on the SiO₂ shows a c-axis orientation by RF sputtering. The crystallinity of the ZnO thin film is influenced by surface conditions of under layer. ZnO thin films have been deposited on bottom electrode, that is Au/NiCr, Au/Ti and Au/Cr, respectively. The Au/Ti/ZnO/Au/Ti/SiO₂ structure thin film bulk acoustic resonator shows the best resonant characteristics in this experiment. The resonant characteristics depend on the crystallinity of the ZnO thin film. The resonant resistance at 205MHz using a Au/Ti bottom electrode is about 8% less than that using a Au/Cr electrode. The X-ray diffraction result shows that the crystallinity of ZnO is greatly influenced by the crystallinity of the bottom electrode. The buffer electrode between an Au electrode and substrate give an influence on both the crystallinity of the ZnO thin film and the resonant characteristics through the Au electrode.

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Metal Organic Decomposition (MOD) has been applied to prepare Barium Strontium Titanate (Ba_1-xSr_xTiO₃) ferroelectric thin film on micromachined Si wafer with an aim to fabricate dielectric bolometer(DB) type infrared image sensor. The detector pixel circuit is a capacitor-capacitor serially connected circuit, with one capacitor of BST film on Si membrane structure and the other on Si bulk structure. When exposed to IR radiation, the capacitance of the IR detecting capacitor on membrane structure changed as a result of the change in dielectric constant against temperature of BST ferroelectric film. Temperature Coefficient of Dielectric constant (TCD) of the MOD made BST (x=0.25, Ba/Sr=75/25) thin film is about 1%/K. Uniform and reproducible capacitance behavior in the BST ferroelectric thin film capacitor on micromachined Si substrate has been confirmed. Chopperless operation has been attained and IR responses of the fabricated sensor also have been obtained with R_v of 0.4kV/W and D^* of 1×10⁸ cmHz^1/2/W, respectively.

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This study shows the possibility of controlling dielectric or piezoelectric properties of PZT thin film by applying strain after the deposition. We investigate the relationship between applied strain and relative dielectric coefficient of PZT films deposited on SUS304 and SUS430 stainless steel. The results show that the relative dielectric coefficient increases with decreasing compressive strain. While the crystal orientation of PZT film deposited on SUS304 coincide with that on SUS430, the residual compressive strain in the former is different from the latter. We compare the dielectric properties of PZT film deposited on SUS304 with that on SUS430 at the same strains in the films. Dielectric properties of the former agree fairly well with those of the latter.

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Through-hole interconnections were fabricated by refilling the through-holes, formed by the optical excitation electropolishing method(1) (OEEM), with indium by the molten metal suction method. In the specimen used for this experiment, through-holes were formed with a density of 11.6 holes/mm² and an aspect ratio of 52. On the wall surfaces of the through-holes, a 500nm thick oxide film was formed by pyrogenic oxidation to provide a dielectric film. The dielectric breakdown voltage of this film was over 300V, and the stray capacity was less than 80pF/hole. Indium sheets of 4N (99.99%) purity were placed on the specimen surface and melted at 350°C by a halogen lamp, and the molten indium was sucked into the through-holes in a vacuum of 0.05 Torr. By this open-type method of sucking molten metal in the air, the whole process could be completed in less than 5 minutes and the through-holes less than 50 aspect ratio could be refilled with indium with an efficiency higher than 90%. To use the refilled holes as through-hole interconnections, a pole or mushroom type solder (Sn: Pb=6.4) bump was formed on the top of the holes by electroplating. The obtained through-hole interconnections had a resistivity of less than 100mΩ and were excellent in gastightness with no leakage exceeding the detection limit of Radiflo leak test (1.0×10^-10Pa⋅m³/sec). Based on the result, it was confirmed that through-hole interconnections having an aspect ratio of 50 and a superior gastightness could be formed, suggesting success in producing self-package type three-dimensional devices.

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The fabrication and characterization of a fiber-optic micro accelerometer for downhole seismic measurement is described. This sensor consists of a Fabry-Perot interferometer using a half-mirror at the end of an optical fiber and a total reflection mirror on a silicon mass suspended with thin beams. When acceleration is applied to the sensor, the intensity of the reflected light is modulated interferometrically according to the displacement of the silicon mass.
The sensor is fabricated by using silicon micromachining and hence is small sized (6.6mm in diameter and 11mm in height) and cost effective. By reason of the small size and the low cost, it is possible to install many sensors in a micro borehole. Since the sensor has not active devices like transistors, it can stand in harsh environment i.e. high temperature. The fabricated sensor has the frequency range from DC to 300Hz, the maximum detectable acceleration of 0.27g and the dynamic range of 36dB.

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The present paper describes a new method for calculating the tribo-charge distribution of a spherical toner particle. The forces which act on the particle adhered on the inner surface of the parallel electrodes connected to the power supply are the adhesion, the gravity and the Coulomb forces. By the movement of the toner particle under these conditions, the tribo-charge can be calculated by the following equation:
q=(8πσgd/3)/(V₁-V₂)
where V₁ V₂ d, σ, g and r are the voltage applied across the upper and the lower electrodes in the case that the toner particle put on the lower electrode is lifted toward the upper one, the voltage in the case that the toner particle gets back again to the lower one, the air gap distance between the two electrodes, the density of the toner particle, the acceleration of gravity and the radius of a toner particle, respectively. By using this method, the charge amounts of the toner particle can be easily obtained.

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Mono-channel taste sensor using polyion-complex LB file is described. The sensing film deposited on the silver plate was dioctadecyldimethylammonium bromide (DOABr) combined by potassium polyvinyl sulfate (PVSK) as an under layer. New method was developed by detecting both parameters of membrane potential change and time response for titration. Five basic taste substances could be experimentally discriminate by these parameters.

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A potential method for evaluating the concentration of gaseous nitrogen oxides in the exhaust gas from the pressurized fluidized bed combustion (PFBC) system was developed, and then its effectiveness was certified in a 71MWe PFBC demonstration plant at Wakamatsu Work, Electric Power Development Co. The total amount of nitrogen oxides (NO, NO₂ and N₂O) in the exhaust gas was closely related with the N content in the coal used as a fuel and contained no thermal-and prompt-NO_x (NO and NO₂) originating from N₂ in air, due to a low combustion temperature of around 1, 130K in the PFBC system. The concentration of NO_x and N₂O was estimabed as a function of the temperature and oxygen partial Pressue in the exhaust gas, if burning coal was specified. By pseudo thermodynamic equilibrium over the fluidized bed under the successive supply of the slurry fuel and pressurized air, conversions of N in the fuel coal into NO_x and N₂O could be expressed by ASH^TR-NO_x and -N₂O equations, respectively, based on the temperature measured by thermocouple and the oxygen partial pressure by a YSZ oxygen sensor. The calculated NO_x and N₂O concentrations by the equations were well agreed with the measured values by commercially available instruments, demonstrating the potential use of this method for rapid and indirect monitoring of gaseous nitrogen oxides in the exhaust gas from the PFBC system.

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Factors responsible for a sidewall formation of thick PZT films prepared by impact based deposition technique were experimentally investigated. An inclination of patterns sidewall is mainly determined by velocity of the impacted particles. For 100μm film obtained by aerosol deposition method a pattern with the sidewall angle 60⁰ was achieved.

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