We have developed a 22 µm pitch and 320 × 240 pixel uncooled IR (infrared) image sensor. For IR detection, we utilized single crystal silicon series p–n junctions, which were fabricated on a SOI (silicon on insulator) wafer utilizing 8 inch CMOS technology and MEMS processes. The p–n junctions were passivated with buried and laminated oxide layers from wet crystalline etching of the silicon substrate. The oxide layers were also utilized to absorb the IR radiation and to form supporting beams. The partially released pixels were utilized as thermal black pixels (TBs) instead of optical black pixels (OBs) for correlated double sampling. The IR image sensor utilizing TBs obtained a thermal image of the human body stably without the smearing phenomenon.
We have developed a 32 μm pitch and 160 × 120 pixel uncooled infrared radiation focal plane array (IRFPA) on SOI by 0.35 μm CMOS technology and bulk-micromachining. For IR detection, we use silicon single crystal series p-n junctions which can realize high uniformity of temperature coefficient and low voltage drift. We have also developed a low-noise CMOS readout circuit on the same SOI which can calibrate the substrate temperature variation in every frame period, comparing two types of pixels, a bulk-micromachined infrared detection pixel and a non-micromachined reference pixel. Then the FPA requires no thermo-electric cooler (TEC) and is mounted on a low-cost standard ceramic package for the consumer products market.
The first study as regard with the application of robotic technology to the field of joint biomechaics was reported more than 20 years ago1). Since then, a variety of studies have employed commercially available articulated manipulators for the joint biomechanical studies1–4). However, such articulated manipulators are generally poor at stiffness and precision although they were basically designed to achieve high speeds of motion while performing tasks in a large work space. To solve the problem, we have previously developed a robotic system consisting of a custom-made 6-degree of freedom (6-DOF) manipulator and a universal force-moment sensor (UFS)5). Referring to the robotic system, the present study was aimed to develop a novel robotic system of rigid body/structure that allows a high-rate displacement/force control of the knee using a velocity-impedance control.
Etch rate control in a 27 MHz reactive ion etching system for ultralarge scale integrated circuit processing ''Notching,'' which is a kind of local side etching caused by charging of pattern structures, is a serious obstacle to achieving tight critical dimension ͑CD͒ control in fabrication beyond quarter micron devices. Although sidewall protection with increased polymer deposition on the sidewall can reduce notching, it tends to enhance the so-called proximity effect, which is the variation of etched profiles observed when the pattern spacing is varied. Therefore, notching has to be suppressed without extra sidewall protection to achieve tight CD control. To solve this problem, we studied the effects of rf bias frequency for both continuous mode and pulse modulated mode electron cyclotron resonance plasma sources with divergent magnetic fields, and found out that lowering the bias frequency can reduce the notching by itself. We found that the notch depth is markedly decreased by lowering the bias frequency from 13.56 MHz to 400 kHz under most conditions. In continuous mode plasma, however, this improvement becomes minimal when the pressure is decreased to reduce the proximity effect. On the other hand, using a pulsed plasma source having a 100 s cycle and 25%-50% duty, we succeeded in suppressing notching even in cases of 1 mT and lower. Consequently, we have achieved a vertical etched profile with minimal proximity effect.
We have analyzed the dominant noise sources in the driving circuit of an uncooled infrared radiation focal plane array fabricated on a silicon-on-insulator (SOI) substrate by 0.35 μm CMOS technology and bulk-micromachining. We found no noise property of SOI-MOSFET inferior compared to those of NMOSs formed on SOI and bulk substrate, respectively. In addition, we reduced the total noise of the sensor chip by designing the current source NMOS sufficiently large, and optimized the operating current of pixel pn-junctions.
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