A new memory cell array structure for high density DRAMs is proposed. This new structure is superior to both conventional open bit line and folded bit line structures when the use of isolation merged trench cells, such as FC cell, are considered. The application of this structure to a 16 M bit DRAM cell array design will be also discussed.

Binary code representation successfully reducing device count for radix-2 Signed-Digit arithmetic has been proposed and an adder using this binary code has been designed. Delay time of addition is estimated at 5.5 ns regardless of digit length using 1.2 µm CMOS technology. The occupied area is almost the same compared with CLA.

An array of monolithically integrated composite-cavity lasers which has been fabricated on the basis of the chemical etching technique is reported. Each composite-cavity laser consists of a laser and an external reflector, and the reflector is used also as a photodetector. The array is designed so that each laser can be operated independently of the other for parallel processing of optical data with high stability operation and independent monitoring capability. Experimental devices have been successfully fabricated.

This letter describes a novel coupled-transmission-line directional coupler using an asymmetrical suspended stripline with unequal conducting strips on both sides of a dielectric substrate. The directional coupler has a rang of coupling values from 5 to 9 dB which is difficult to be realized by a conventional symmetrical suspended stripline coupler.

Feed back control approach for stabilization phase modulator index of PZT phase modulator in all-fiber optic gyroscope is described. Dual core fiber interferometric sensor is applied to detect phase modulating index of PZT cylinder. Fluctuation of modulator versus temperature variation can be approximately eliminated 15 dB by this method.

This letter reports the estimation for the decay rates of ab and a in a 758.8 nm He-Zn laser under the actual lasing condition. The values of ab and a are estimated to be 195 MHz and 145 MHz, respectively at He pressure of 9.0 Torr.

Optical pulse compression by using optical fiber and either conventional Gires-Tournois interferometer or modified one, instead of the grating pair is analysed. The separation of adjacent two pulses by such separation system is also proposed and analysed for the first time.

An analogue equipment is developed and described, which can automatically identify and track the magnetospheric whistler signal so that we can measure the amplitude ratio and phase difference between two horizontal magnetic field components of each whistler over a wide frequency range (6 to 3 kHz) and then we can study the ionospheric transmission characteristics of whistlers.

Hot carrier effects in narrow-channel MOSETs are investigated. With decreasing channel width below 1µm, the ratio of substrate to channel currents show marked increase. By using the newly developed full three-dimensional process/device simulation system, two significant causes of the hot carrier effects are clarified.

The relation between driving current and active again drift in 600 MHz band 2-port SAW resonators on quartz substrate is clarified and the threshold level causing the metal-migration is grasped. A practical method for measuring the driving current is proposed.

The effects of current gain and emitter resistance on the switching performance of ECL gates with GaAs/AlGaAs HBTs are analyzed by circuit simulation. A minimum current gain of 10 and a maximum emitter resistance of less than one fifth of the load resistance were found to be necessary for stable ECL inverter operation.

Mechanical interaction in a multi-actuator is suppressed by utilizing a trapezoidal driving current. Fundamental performance of this method is examined experimentally and analytically.

Switching devices capable of handling more than 800 V exhibit relatively large switching loss. A new current feedback Bi-MOS consisting of a Bipolar Junction Transistor, MOS-FET and current transformer is proposed in this note. The new device reduces switching loss in 100 kHz operation and is expected to result in a DC-DC converter efficiency greater than 90%.

Emitter crowding effect and emitter Gummel number of amorphous SiC: H emitter HBT have been investigated. Collector current density has been remarkably enhanced by narrowing the emitter stripe width. The emitter Gummel number has been estimated as high as 21014s/cm4.

The threshold current Ith of a 1.5 µm range InGaAsP/InP λ/4-shifted DFB laser with low-reflectivity ends was theoretically expected to be 10 mA or less. Experimentally, Ith of 14-16 mA at 20 and the sub-mode suppression ratio of about 35 dB or more in the temperature range of 10-70 were obtained.

A 1.3 µm edge-emitting LED is used to launch an average optical power of 13.7 dBm into single-mode fibers. This permits analog video signal transmission over a distance of 42 km with a loss margin of 5 dB. No degradations of DG, DP, and signal-to-noise ratio have been observed.

A 20 GHz band monolithic low noise amplifier combining improved SAINT-FET technology and optimized circuit design has been developed. The amplifier has a measured noise figure of less than 3.5 dB with a minimum gain of 4.2 dB over the 18.5 GHz to 20 GHz range. The optimal noise figure is 2.9 dB with a gain of 5.5 dB at 19 GHz. Standard threshold-voltage deviation of the process monitor FRTs is only 70 mV over the entire area of the 2-inch wafer.

The modulation performance of traveling-wave type LiNbO3 guided-wave light modulators with coplanar waveguide structure is studied. The analysis shows that the use of a y-cut plate offers a low voltage modulation with decreased electrode separation although the characteristic impedance becomes low.

Using buffered GaAs MESFET logic (BFL) circuits with source follower architecture, ultra-high-speed, master-slave, flip-flop circuits were designed and fabricated. Newly-developed buried p-layer SAINT-FETs with 0.5 µm gate length by electron-beam lithography were used in the frequency divider IC process. A maximum operating frequency of the binary frequency divider was 6.8 GHz with a power consumption of 350 mW. Using dislocation free wafers, a 100% fabrication yield for more than 3.3 GHz operation was attained from four wafers; all frequency divider chips from one wafer operated at more than 5.1 GHz. Using the Advanced SAINT process, a maximum operating frequency of 9.2 GHz with a power consumption of 290 mW was also obtained based on the same circuit design.

A new threshold voltage formula is derived for a U-shaped gate MOSFET where the gate oxide becomes thicker at both channel ends. It is found that when charge-sharing effect due to source/drain-junctions is not accounted for, threshold voltage increases with decreasing channel length, exhibiting an inverse short-channel effect (ISCE). When charge-sharing effect is taken into account, the ISCE reduces remarkably, resulting in a flat threshold voltage characteristic over a wide range of channel lengths. Computer simulations using a two-dimensional device simulator show a good agreement with these analytical findings.