前中 一介

FETが超高周波領域で使用される際、ゲート電圧給電点をゲートの片端に設けた場合にゲート幅方向に沿って駆動電圧の減衰や位相の回転などが生じる。これがFETの伝達特性にどのような影響を及ぼすかをn形GaAsMES-FETの帯状ゲートに関して解析実験し、ゲート幅に対する遮断周波数特性について考察した。

近年注目を集めている振動型シリコンレートセンサでは振動片の共振を用いることにより、高感度なデバイス設計が可能である。しかしながら、高感度化にともなう安定度の低下が問題となる。本報告では高感度かつ高安定なデバイスの構造及び駆動方法を提案する。

ソースコイルの発生する磁界を任意の位置においた検出コイルにより測定すれば、得られた出力を逆演算することにより、両者の相対的位置を検出することが出来る。本研究では、この逆演算にニューラルネットワークを用いた位置および動き検出システムを提案する。

This paper deals with the silicon angular rate sensor which has a cantilever beam as a vibration mass. Under the open loop control of the mass movement, the mechanical quality-factor influences the sensitivity and stability of the sensor. In this paper, the simple analysis, the tuned device with respect to the sensitivity, and modes of the vibration of the beam which influences the stability are described.

マイクロマシニング技術を用いた振動型シリコンレートセンサでは、Q置の非常に高い素子が作製できる。このため振動子のレート検出方向の機械的共振周波数ωοと、振動子をレート検出方向と直交して駆動する周波数ωの関係がセンサの出力ゲイン及び応答速度の重要な問題となる。そこで本研究では理論的解析により最適な周波数設定の指針を示す。

マイクロマシニング技術を用いたシリコンレートセンサ(角速度センサ)の、加速度に対する出力(加速度感度)を低減するため、解析的にその発生機構を明らかにしたので報告する。

Silicon angular rate sensors are studied. The structure and fabrication process are quite simple and mass-producible. The silicon rate sensors have an oscillation bar and detection electrodes on a glass base. The oscillation bar and the detection electrodes are simultaneously formed by a silicon anisotropic etching process. The oscillation bar is vibrated at its resonance frequency by a piezo-actuator. The applied angular rate generates the Coriolis' force to the oscillation bar, and the oscillation bar deviates from its normal orbit of the vibration. This deviation makes the capacitance change between the oscillation bar and the detection electrodes. The capacitance change is converted into the voltage level which is the output voltage of the sensor. The test device shows a sensitivity of about 20 mV/(rad/s) and a linearity of 2% FS (full scale). The resolution (or equivalent noise level) is now 0.1 rad/s. In this paper, the fabrication process and the measured data of the test device are presented. Moreover, the improved structure with respect to the acceleration sensitivity is discussed. © 1994.

This report introduces the activity of education and research in our clean room. With the move of our college at 1990,various apparatuses for the fabrication of the bipolar-and nMOS-IC have been introduced in the clean room. At first, we installed electric furnaces, a mask aligner, a vacuum evaporator, a wire bonding machine, etc. Next, the fabrication processes of the integrated circuit including the bipolar and nMOS technology were established. Moreover, a mask fabrication system was build up. Now, we have two courses of the technical education for 4th and 5th grades and the special resarch course for 5th grade for the process technology of integrated ciruits. The report shows the outline of such courses.

The offset voltage shift in Hall cells due to a mechanical strain (piezoresistive effect) was studied. The experiment shows that the vertical Hall effect, which has a compatible structure with a bipolar integrated circuit, has an extremely small offset voltage shift against mechanical strain in contrast with conventional Hall cells. © 1993, The Institution of Electrical Engineers. All rights reserved.

A monolithic integrated magnetic sensor realizing omnidirectional measurement is presented. This monolithic integrated sensor consists of three Hall cells which detect magnetic components in x, y, and z directions and the bipolar circuit which converts the output signal of Hall cells VX, VY, and VZ into its absolute value (=(V2X + V2Y + V2Z)1/2). For the magnetic detector, a new “lateral Hall cell” is proposed to detect the magnetic components parallel to the chip surface (x, y directions). The three‐dimensional (3‐D) magnetic detection has been realized by combining two lateral Hall cells and a conventional epitaxial (lateral) Hall cell (for z direction). The signal conversion circuit uses a Gilbert multiplier for square calculation and a translinear circuit for a root circuit, with a total device count of 158 elements. The test device realized an omnidirectional magnetic measurement with a maximum error of ±4 percent, sensitivity of 14 V/T, and a temperature coefficient of 2100 ppm/°C in the magnetic flux range of −250 to +250 mT. Copyright © 1992 Wiley Periodicals, Inc., A Wiley Company

An analysis of the sensitivity of a pnp lateral magnetotransistor (LMT) fabricated in bipolar technology is presented. In addition, the role of the n+-buried layer is studied. The devices were designed as differential LMTs. It has been found that the change in sensitivity of pnp LMT increases by one order of magnitude if the n+-buried layer is not omitted. The obtained sensitivity is the highest ever reported for a pnp LMT.

In this report, an integrated magnetic sensor which offers the direction of the applied magnetic field is presented. This integrated sensor contains a two-dimensional magnetic detector which detects the in-plane magnetic vectors, Bx and By, and a signal conversion circuit which calculates the direction θ (=tan-1(By/Bx)) using the translinear circuit technology. This integrated magnetic sensor has not only the direction output but the output for the intensity (the absolute value) of the applied magnetic field. The test device was fabricated using the standard bipolar analog IC technology and its characteristics were examined. As a result, the direction of the applied magnetic field was obtained with maximum error of ± 2% full-scale deflection. © 1990.

Recent silicon magnetic sensors and integrated sensors are described. The silicon magnetic sensors, whose fabrication is compatible with the standard IC process, are in the limelight because they can easily be incorporated into integrated circuits and it may be possible to realize intelligent sensors. However, although there are some cases of successful integrated magnetic sensors on the market, such as the Hall IC, their function is too simple to call them intelligent sensors. In this paper the present situation is described, and attention is focused on the coming intelligent sensors. © 1990.

A new class of integrated magnetic sensors, a magneto-operational amplifier (MOP) is presented. The MOP is a universal magnetic sensor which can be used for many purposes. The principle of the MOP is a feedback amplifier similar to the usual operational amplifier which is widely used for realizing any analog function. In order to make use of the advantages of an operational amplifier, the MOP has similar components: a differential amplifier stage which includes a magnetic detector; a sufficiently large gain amplifier; and an output stage. By changing external feedback elements, the MOP can realize various magnetic operations, such as a linear magnetic sensor, a magnetic switch, a magnetic filter, etc. In this paper experimental results of some applications of the MOP are given. © 1990.

We report experimental results that clarify the operation of vertical magnetotransistors. The experiments consist of a direct measurement of the possible presence of any Hall voltage in the base region, and allow the dependence of sensitivity on the emitter length and the base impurity concentration to be studied. The experimental results are discussed with respect to the two well-known models of device operation: carrier deflection and emitter injection modulation. The results indicate that the operation mechanism is based on carrier deflection, with no contribution whatsoever from emitter injection modulation. © 1989.

Computations using a two-dimensional numerical model as well as experimental data obtained from Hall probe measurements indicate the presence of a weak Hall field along the emitter-base junction of magnetotransistors. This field is too minute to cause any appreciable “emitter injection modulation” or “asymmetric injection,” an effect that has been widely invoked to describe the magnetic sensitivity of magnetotransistors (MT) fabricated in standard IC technologies. The results presented in this paper, as well as our previous findings, lead us to conclude that emitter injection modulation as an MT operating principle can be ruled out in favor of carrier deflection (for linear MT's) and magnetoconcentration (for nonlinear MT's). © 1989 IEEE

Novel vertical Hall cells which detect the magnetic field parallel to the chip surface were developed using the standard bipolar technology. In the devices, an n+ buried layer makes a vertical current flow and introduces the sensitivity parallel to the chip surface. A sensitivity of 75 V/AT was measured. © 1987, The Institution of Electrical Engineers. All rights reserved.