The prospects for ultrahigh-speed VLSI GaAs digital logic

Recent advances of GaAs integrated circuit fabrication technology have made possible the demonstration of ultrahigh performance GaAs digital ICs with up to 64 gate MSI circuit complexities and with gate areas and power dissipations sufficiently low to make VLSI circuits achievable. The authors evaluate, based on the current state of GaAs IC technology and the fundamental device physics involved, the prospects of achieving an ultrahigh-speed VLSI GaAs IC technology. GaAs IC fabrication and logic circuit approaches is reviewed. The experimental performance results are compared for the leading GaAs logic circuit approaches, both for simple ring oscillators and for more complex sequential logic circuits.     

超高速单电源GaAs判决再生电路

设计并模拟分析了光纤通信用超高速单电源 Ga As判决再生电路 ,采用非掺 SI Ga As衬底直接离子注入、1μm耗尽型 Ga As MESFET、平面电路工艺研制出单片 Ga As判决再生电路。实验测试结果表明 ,该电路可对输入信号进行正确的“0”、“1”判决 ,并经时钟抽样后 ,输出正确的数字信号 ,传输速率可达 2 .8Gbit/s,可用于覆盖 2 .5Gbit/s系列光通信系统     

高压微型砷化镓太阳电池的研究

介绍了高压微型砷化镓太阳电池的研究情况,研究了MOCVD砷化镓外延片的结构设计和制作,研究了高压微型砷化镓太阳电池串联结构设计和器件工艺的情况。研制的高压微型砷化镓太阳电池在1cm2面积内串联了118个电池单元,每个电池单元有效面积为500μm×400μm。在AMO光强下,开路电压大于80V,短路电流大于50μA。     

The prospects for ultrahigh-speed VLSI GaAs digital logic

Recent advances in the state of GaAs integrated circuit fabrication technology have made possible the demonstration of ultrahigh performance (tau_{d} sim 100ps) GaAs digital IC's with up to 64 gate MSI circuit complexities and with gate areas and power dissipations sufficiently low to make VLSI circuits achievable. It is the purpose of this paper to evaluate, based on the current state of GaAs IC technology and the fundamental device physics involved, the prospects of achieving an ultrahigh-speed VLSI GaAs IC technology. The paper includes a performance comparison analysis of Si and GaAs FET's and switching circuits which indicates that, for equivalent speed-power product operation, GaAs IC's should be about six times faster than Si IC's. The state of the art in GaAs IC fabrication and logic circuit approaches is reviewed, with particular emphasis on those approaches which are LSI/VLSI compatible in power and density. The experimental performance results are compared for the leading GaAs logic circuit approaches, both for simple ring oscillators and for more complex sequential logic circuits (which have demonstrated equivalent gate delays as low astau_{d} = 110ps).     

GaAs／Si衬底电路制备中Ge元素分布的研究

Ｓｉ衬底上外延ＧａＡｓ材料是微电子学研究的重要课题之一，本文介绍了以大直径的ＧａＡｓ／Ｓｉ材料取代ＧａＡｓ衬底的工艺技术，对Ｇｅ元素在ＧａＡｓ／Ｓｉ集成电路中的分布影响进行了俄联电子能谱分析研究，并确定了该技术在大规模集成电路中的应用价值。     

AlGaAs/GaAs HBT的低频噪声

测试了AlGaAs／GaAsHBT的低频噪声，并将测试结果分解为1／f噪声、G－R噪声和白噪声，阐述了它们的产生机理，在此基础上建立了AlGaAs／GaAsHBT输入噪声电压的等效电路模型，该模型有助于AlGaAs／GaAsHBT电路的CAD。     

Determination of the Electrode Capacitance Matrix for GaAs FET's

In this paper, a method is presented which provides the electrode capacitance matrix for GaAs FET's. The method incorporates a Green's function, valid for conductors printed on or embedded in a grounded substrate, with the moment method technique. Although calculations for various geometries of printed conductors are considered, emphasis is placed on the computation of self- and mutual-capacitances for the source, gate, drain equivalent circuit of a GaAs FET. As an example, the speed power characteristics of a depletion-rnode GaAs FET inverter circuit are examined, as a function of device width, pad and gate length.     

11.GHz GaAs Power MESFET Load-Pull Measurements Utilizing a New Method of Determining Tuner Y Parameters

A Ioad-pull technique utilizing a new method of determining tuner Y parameters is proposed for huge-signal characterization of microwave power transistors. Large-signal input-output transfer characteristics of an active circuit containing a GaAs FET and an input matching circuit are measured by inserting a microstrip tuner between the active circuit output drain terminal and the 50-Omega load. The microstrip-tuner Y parameters are determined by comparing the dc bias-dependent small-signal S parameter S/sub 22/ of the active circuit and that of the circuit which contains the active circuit and microstrip tuner. The reflection coefficient presented to the active circuit output drain terminal is derived from tuner Y parameters. Optimal load impedances for output power, obtained with this new Ioad-pull technique, are used to design X-band GaAs FET power amplifiers. An 11-GHz power amplifier with a 3000-mu m gate-width FET chip delivers 1-W microwave power output with 4-dB gain in the 500-MHz band.     

High frequency GaAs switched capacitor filter implemented with GaAs insulated gate FET switches

A switched capacitor filter implemented with 5 mu m GaAs IGFET switches and GaAs MESFET operational amplifiers is presented. The circuit is clocked at 25 MHz. By scaling to 1 mu m IGFETs, a switching speed of about 625 MHz should be attainable. Use of GaAs IGFET switches is shown to greatly reduce power consumption and complexity of the circuit. The low frequency switching instability of the GaAs IGFET is shown to be of no consequence in this application.<>     

基于InGaP/GaAs HBT的X波段MMIC功率放大器研制

研制了X波段的InGaP/GaAs HBT单级MMIC功率放大器,该电路采用自行开发的GaAs HBT自对准工艺技术制作.电路偏置于AB类,小信号S参数测试在8～8.5GHz范围内,线性增益为8～9dB,输入驻波比小于2,输出驻波比小于3,优化集电极偏置后,线性增益为9～10dB.在8.5GHz进行连续波功率测试,在优化的负载阻抗条件下,P1dB输出功率为29.4dBm,相应增益7.2dB,相应PAE〉40%,电路的饱和输出功率Psat为30dBm.     

High-speed integrated logic with GaAs MESFET's

The feasibility of using GaAs metal-semiconductor field-effect transistors (GaAs MESFET's) in fast switching and high-speed digital integrated circuit applications is demonstrated. GaAs MESFET's with 1-/spl mu/m gate length are shown to have a current-gain-bandwidth product f/SUB T/ equal to 15 GHz. These devices exhibit a 15 ps internal delay in a large-signal switching test. A simple logic circuit consisting of MESFET's and Schottky diodes was monolithically integrated on a semiinsulating GaAs substrate. This logic circuit exhibits a propagation delay of 60 ps with no output load, and 105 ps when its output is loaded by three similar logic gates. A useful bandwidth of approximately 3 GHz is observed.     

Ultra-Broad-Band GaAs Monolithic Amplifier

GaAs monolithic IC design and fabrication techniques suitable for baseband pulse amplification have been developed. The developed GaAs monolithic amplifier has a two-stage construction using two source-grounded FET's. To reduce input VSWR without serious noise-figure degradation, an inter-gate-drain negative feedback circuit was adopted. An interstage circuit is a dc-coupled circuit consisting of an appropriate impedance transmission line. Gate voltage for the second-stage FET is self-biased. The amplifier has 13.5-dB gain over the 3-dB bandwidth from below 500 MHz to 2.8 GHz. Less than 6-dB (7-dB) noise figure was obtained from 700 MHz to 2.2 GHz (150 MHz to 3 GHz). Input VSWR is less than 1.5     

Ultra-broad-band GaAs monolithic amplifier

GaAs monolithic IC design and fabrication techniques suitable for baseband pulse amplification have been developed. The developed GaAs monolithic amplifier has a two-stage construction using two source-grounded FET's. To reduce input VSWR without serious noise-figure degradation, an inter-gate-drain negative feedback circuit was adopted. An interstage circuit is a dc-coupled circuit consisting of an appropriate impedance transmission line. Gate voltage for the second-stage FET is self-biased. The amplifier has 13.5-dB gain over the 3-dB bandwidth from below 500 kHz to 2.8 GHz. Less than 6-dB (7-dB) noise figure was obtained from 700 MHz to 2.2 GHz (150 MHz to 3 GHz). Input VSWR is less than 1.5     

GaAs DCFL电路研究

给出了对ＤＣＦＬ电路单元的研究，包括电路设计和用先进的Ｐ埋层自对准栅工艺制作电路的实验结果。表明它可以适用于大规模ＧａＡｓＤＣＦＬ电路的设计和制造。     

Compensation-circuit to improve radiation-hardness in GaAsdigital-circuits, based on X-ray studies

Earlier results have shown that GaAs devices do not exhibit appreciable degradation up to a radiation dose of nearly 10⁸ rad (GaAs). The results of this work suggest that GaAs devices and circuits are sensitive to radiation exposure at dose levels below 10⁸ rad(GaAs). Degradation was observed in E-MESFET and D-MESFET parameters and in circuit performance for devices which were designed and fabricated in a 1.2 μm GaAs process, when exposed to varying doses of 1.49 keV X-rays in the range 40-65 Mrad (GaAs). The degradation is attributed to the change in the properties of the MESFET channel region, caused by the transport of the atomic hydrogen from the passivation layer to the channel. A compensation circuit, based on the observed behavior of radiation effects on GaAs devices, has been designed to improve the radiation insensitivity of GaAs (E/D) based circuits under SPICE (Simulation Program with IC Emphasis) simulated conditions. Its usefulness is demonstrated through a DCFL inverter circuit up to nearly 10⁸ rad (GaAs) dose level. The results of this work can be used in the design of complex-function radiation-insensitive DCFL based circuits     

GaAs switched capacitor DC-to-DC converter

A switched capacitor DC-to-DC negative converter fabricated in GaAs MESFET technology is introduced in this paper. The converter has an oscillator that runs at 250 kHz, and requires two external capacitors, 0.1 and 1 μF. The converter runs off a wide range of supply voltage, 2 to 10 V, and has a typical output impedance of 75 Ω. A typical open circuit voltage conversion efficiency of 99.6% is achieved. The circuit can be integrated with other GaAs circuits to provide an on-chip negative supply. Measured, simulated and analytical results are introduced in this paper     

一种GaAs HBT微波功率放大器的设计

介绍了C波段宽带固态功率放大器的设计方法和实际测试结果。该放大器用于某雷达发射组件推动级,采用GaAs HBT器件,宽带匹配电路、直流偏置、负反馈设计。根据负载牵引分析,运用微波仿真软件对功率管的输入、输出阻抗匹配电路及其偏置电路进行优化仿真设计,增加电源控制电路保证可靠性,研制出了符合整机指标要求的放大器。     

An improved GaAs device model for the simulation of analog integrated circuit

This paper describes an improved device model of GaAs MESFETs and heterojunction FETs for the design and analysis of analog integrated circuits. The proposed device model provides a new expression for the current and the capacitance of the device,which gives excellent agreements with experimental data for all regions of device operation. For the expression of the low frequency anomalies of GaAs devices, an improved technique with an equivalent circuit are presented to model the frequency dispersion of the transconductance and the drain conductance of the device, which give a good agreement with the experimental data of both the frequency dispersion and the lag effect of the device. The new device model proposed here clearly provides a superior prediction of the performance of GaAs analog integrated circuit.     

An ultrahigh-speed GaAs MESFET operational amplifier

A wide-bandwidth GaAs MESFET operational amplifier is reported, with a 65-dB DC gain and a 20-GHz gain-bandwidth product at 500 MHz. The circuit uses a variety of local feedback techniques to enhance the overall gain. The use of an undoped GaAs buffer, grown at a relatively low temperature (≈300°C), eliminates backgating and light sensitivity. The circuit was fabricated in an 80-GHz f_T MESFET process, with 0.2-μm electron-beam defined gates. The high levels of 1/f noise, MESFET frequency-dependent output conductance, and large offset voltage standard deviation limit the application of the circuit to moderate precision applications     

Numerical modeling of energy balance equations in quantum well AlxGa1-xAs/GaAs p-i-n photodiodes

The energy balance equations coupled with drift diffusion transport equations in heterojunction semiconductor devices are solved modeling hot electron effects in single quantum well p-i-n photodiodes. The transports across the heterojunction boundary and through quantum wells are modeled by thermionic emission theory. The simulation and experimental current-voltage characteristics of a single p-i-n GaAs/Al _xGa_1-xAs quantum well agree over a wide range of current and voltage, The GaAs/Al_xGa_1-xAs p-i-n structures with multi quantum wells are simulated and the dark current voltage characteristics, short circuit current, and open circuit voltage results are compared with the available experimental data, In agreement with the experimental data, simulated results show that by adding GaAs quantum wells to the conventional cell made of wider bandgap Al_x Ga_1-xAs, short circuit current is improved, but there is a loss of the voltage of the host cell, In the limit of radiative recombination, the maximum power point of an Al_0.35Ga_0.65As/GaAs p-i-n photodiode with 30-quantum-well periods is higher than the maximum power point of similar conventional bulk p-i-n cells made out of either host Al_0.35Ga_0.65As or bulk GaAs material