Recently demands for thermal IR sensors are increasing for industrial or automotive uses. This is due to their simple structure and operation without cooling. An advance in micromachining techniques has enabled the realization of thermally isolated structures and the miniaturization of IR detection cells for an array sensor. Various types of silicon micromachined IR sensors with cantilevers or diaphragms have been developed, mainly using pyroelectric or thermopile detecting techniques. Among them are the thermopile IR sensors utilizing the Seebeck effect of silicon. This type of sensors has the potential of being used in an array for imaging applications, due to considerable integration from their compatibility with the IC fabrication process, although someapplications require larger responsivities.
This paper describes the fabrication, testing and modeling of the thermal resistance of an IR sensor using p-type/n-type polysilicon thermocouples on a dielectric diaphragm and incorporating a heater resistor on the center of the diaphragm. This structure increases the thermal resistance by eliminating metal interconnections on the diaphragm and doubles the output of each thermocouple compared to the Si/metal type. The measured responsivity of the sensor with a 1mm square diapharagm using thermal excitation was 83.5V/W, which was in reasonable agreement with the calculated value, although the one, measured using optical excitation by a laser diode, was a little smaller. A larger responsivity will be obtained through the design optimization of this sensor.

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A new fabrication process of micromachines using oxidized porous silicon film has been developed. The porous silicon film with thickness of several micrometers was made from p-type silicon by anodization in 46% HF solution and at a constant current density of 30mA/cm². The porous silicon was thermally oxidized at 1, 100°C for 30 min. in dry O₂ gas. Two types of microbridges were fabricated by using oxidized porous silicon as a sacrificial layer. It is shown that thick oxide layer can be selectively formed by using the porous silicon.

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We describe a new method for measuring the mechanical properties of micro mechanical structures by using a force microscope. A high resolution scanning force microscope (SFM) system using a laser heterodyne interferometory was developed. The interaction between the SFM probe and the sample was investigated under the condition that the sample was so thin as to be deflected by the interaction force. The SiO₂ micro cantilevers were fabricated by the lithographic process and the spring constants were determined from the SFM force curves. The measured spring constant was used to obtain the Young's modulus of the material. Moreover, the Young's modulus of thin aluminium film coated on the cantilever was obtained by this method. This method is simple and applicable to the evaluation of elasticity for the micro mechanical structures.

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A friction force acts at the surface of elements and it's not affected by the volume of elements. Therefore, with the decrease of the size of moving elements, a knowledge of friction is becoming important to analyze movements of micro-machines. In the present paper, we studied the static friction coefficient for various thin films. In order to measure the static friction coefficient, millimeter-size mover was driven electrostatically on those thin films. The electrostatic forces which can drive the mover are different among those thin films because of differences in the friction coefficient. Therefore, we determined the static friction coefficient from the minimum electrostatic force. It was found that the friction coefficient of SiO₂ thin film against metalic thin films show a smaller value. However, the friction coefficient between SiO₂-SiO₂ thin film shows a little larger value. It was also found that the friction coefficient of thin films show a little larger value than that of lump.

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New concept of electrostatic microactuator is proposed. It consists of many distfibuted driving units. Each driving unit has two wave-like electrodes which are insulated and pulled each other by electrostatic force. As the driving units have narrow gap portions, the strong electrostatic force enough to deform is obtained. When voltage is applied between the electrodes, the microactuator shrinks by the electrostatic force. We simulated the behavior of the actuator using FEM analysis, and a macro model actuator was fabricated. Its behavior was nearly equal to the result of a simulation.

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In this paper, the design, the fabrication and the operation of electro-static microactuators with sub-micron gaps are reported. As the fabrication of sub-micron gap we employed a technology called "Oxidation Machining" that aims at the fine tuning of gap width. Micro-resonator with sub-micron gaps were fabricated by this technology. The resonator with 0.3μm gap can be operated under 11.5V (peak) with the amplitude of ±5.2μm. Then, a novel post-releasing fabrication called "Post Release Positioning" was invented. By applying this technology, the linear actuator, which changes its position when DC voltage is applied, was fabricated. The linear actuator with 0.2μm gap moved 3.6μm when 11.1V was applied. The relationship between square of applied voltage and the displacement of this linear actuator is very linear; that means this actuator is capable of fine position control. The experimental performance of the actuator is compared with the theoretical calculation.

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In this paper, the design, the fabrication and the operation of two dimensional micro actuators using Yttrium High Temperature Super-Conductors (HTSC) in vacuum condition are reported. This microactuator consists of two parts; (a) a slider made by a permanent magnet, (b) a stator with patterned electrodes on bulk HTSC. The slider is levitated by repulsive force between the magnet and HTSC, when HTSC is cooled by liquid nitrogen. We can control the position of the slider by switching current in electrodes using Lorentz forces between the current and the magnet. The maximum speed of the sliders is 37mm/s at the driving current of 400mA. Two dimensional position control of the slider is achieved in this study with strokes of a few millimeters for each direction.

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Electron energy distribution functions (EEDF) in argon RF plasmas have been measured by using an improved driven probe. The presence of RF potential fluctuations between probe and plasma distorts a Langmuir probe characteristic. Therefore it introduces large errors into plasma parameters. The improved method, which removes the effect of the RF fluctuation on probe characteristics, consists of superimposing the fluctuation of the space potential measured by an emissive probe to the dc voltage applied to the probe. It offered an efficient improvement of probe characteristics. This technique was applied to the measurements of EEDFs in argon plasmas at 13.56MHz. The measured EEDFs in the RF plasmas were non-Maxwellian. It was found that the high energy electrons present in the vicinity of the boundary between the powered electrode sheath and plasma. The electrons will play an important role to maintain the RF discharges.

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This paper describes experimental and analytical results of electromagnetic pulses from a charged copper pipe. Electromagnetic pulses from a copper pipe were measured by EMI type antennas (a loop antenna, a biconical antenna, and a double ridged guide antenna). In this paper, electromagnetic energy of the electromagnetic pulses was analyzed by integrating enegy spectrums of three frequency domains (1-30MHz, 30-300MHz, 300-750MHz).
As a result, the analysis shows that radiated electromagnetic energy by discahrge events does not always increase in propotion to charging voltage. In addition, high speed touch discharges by charging voltgae of 7 or 10 kV increase electromagnetic energy especilly in the frequency region of 300-750MHz.

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Monte Carlo Simulation of a-Si: H thin film growth deposited by plasma CVD are carried out to examine the morphology model of a-Si: H in the terms of film groth reaction, etching reaction by atomic hydrogen and surface diffusion of silane radicals along the surface. A model have been proposed by us(1) based on various experimental facts in which the morphology of a-Si: H consists of Si cluster regions and Si-H alloy regions. Experimentally, cluster regions seem to increase and alloy regions decrease with increasing substrate temperature, respectively. The simulated results about the hydrogen content and graphics turned out to support our proposed model. The physical phenomena depending on substrate temperature such as Staebler-Wronski effect and carrier drift mobility can be explained well by the results of this Monte Carlo Simulation.

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