砷化镓MESFET器件的电路模拟

临于器件模拟参数在电路模拟中的重要性，本文选择了较为理想的模型参数提取方法－－统计试验法，并从理论上解决了该方法在迭代求解过程中存在的隐函数问题，以及解的唯一怀问题。同时提出了加速求的方法。在此基础上设计的软件可获得精确的器件模型参数。该软件与通用的ＳＰＩＣＥ３集成为一个针对ＧａＡｓＭＥＳＦＥＴ器件的电路模拟系统。本文给出了该系统对不同的电路形式基不同的器件参数下的模拟结果，为我们的ＧａＡｓ６００     

基于MESFET的GaAs基微加速度计的设计与性能测试

利用金属-半导体结型场效应晶体管(MESFET)作为微加速度计的敏感单元,设计一种4梁-质量块微加速度计结构.通过ANSYS分析软件进行仿真,敏感单位放置于悬臂梁根部的应力最大处,以获得最大的灵敏度.将封装好的微加速度计结构,利用惠斯通电桥测试电路,检测不同载荷下的输出特性,验证了微加速度计的力电耦合效应.测试结果表明,该微加速度计的线性度较好,其最大加载范围可达到24 g,且饱和区的灵敏度可达到4.5 mV/g,为高灵敏微传感器的研究奠定了一定的基础.     

GaAs功率场效应管失效中源一漏烧毁现象的SEM／SAM研究

采用光学显微镜、扫描电子显微镜（ＳＥＭ）及扫描俄歇微探针（ＳＡＭ）等表面分析技术对ＧａＡｓ功率场效应管（ＦＥＴ）源－漏烧毁失效现象进行了分析研究。ＳＥＭ分析结果表明，源－漏烧毁失效的表面形貌状况较为复杂，烧伤区域的表面形态不尽一致。有源极烧毁较为严重的情况，也有漏极烧伤较严重的情况。ＳＡＭ分析结果说明，源－漏烧毁ＦＥＴ中烧毁处附近的外表完好的源、漏条Ａｕ薄膜下欧姆接触金属薄膜层已完全消失，烧毁源、漏条部位表面化学元素有Ｃ、Ｏ、Ｔｉ、Ｎ和Ｇａ，其中Ｃ、Ｏ在表层几十纳米深度内均有相当高的含量。结合分析结果，讨论了源－漏烧毁的物理机理。     

微波GaAs金属－半导体场效应管可靠性研究的进展

综述了近年来微波ＧａＡｓＭＥＳＦＥＴ可靠性的研究进展。重点介绍了影响其可靠性的因素如栅肖特基结和源／漏欧姆结的相互扩散及表面效应等。     

GaAs－InP复合材料的外延生长方法及金属半导体场效应晶体管器件制备

提出了一种新的生长过渡层的方法，并利用低压金属有机气相外延技术在ＩｎＰ衬底上生长出高质量ＧａＡｓ外延材料，用Ｘ射线双晶衍射测得５μｍ厚ＧａＡｓ外延层的（００４）晶面衍射半峰高宽（ＦＷＨＭ）低至１４０ａｒｃｓｅｃ。并制出ＧａＡｓ金属半导体场效应晶体管（ＭＥＳＦＥＴ），其单位跨导为１００ｍｓ／ｍｍ，可满足与长波长光学器件进行单片集成的需要。     

高速光纤通信用定时恢复判决电路

对光纤通信用定时恢复判决电路进行了研究,设计了由1μm耗尽型GaAs金属－半导体势垒场效应晶体管（MESFET）器件构成的判决电路和时钟提取电路。判决电路的基本单元为源耦合场效应晶体管逻辑（SCFL）电路,时钟提取电路由预处理器和锁相环构成。模拟分析表明,时钟提取电路可从输入信号中提取判决电路所需的时钟脉冲,频率达2．5GHz,判决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,传输速率达2．5Gbit/s。实测电路可正确判决,时钟抽样后,输出正确的数字信号,传输速率达2．5Gbit/s。     

Al0.15Ga0.85As／GaAs与In0.15Ga0.85As／GaAs甚长波QWIPs响应率的仿真对比

对In0.15Ga0.85As／GaAs和Al0.15Ga0.85As／GaAs两种甚长波段量子阱红外探测器（QwIP）响应率进行计算。采用物理模型与等效电路模型，结合Crosslight和Spice等软件详细表征了这两种QWIPs的吸收系数、暗电流、响应率、量子效率等物理特性。结果表明随外加偏压的升高QWIP的响应率增加，T=40K时，In0.15Ga0.85As／GaAs QwIP的响应率明显比Al0.15Ga0.85As／GaAs QWIP高出2倍以上，通过对量子效率的对比，使仿真结果得到验证。     

High‐temperature device performance and thermal characteristics of GaAs MESFETs on CVD diamond substrates

The temperature degradation and high‐temperature characteristics of GaAs FETs on CVD diamond heat sinks were investigated by modeling the high‐temperature electrical characteristics for GaAs MESFETs and by experimentally measuring the elevated‐temperature degradation. The bias region for the Zero‐Temperature Coefficient (ZTC) was determined. The thermal characteristics were determined by infra‐red microscopy and the results were correlated with a finite element analysis calculation of GaAs FET thermal distribution. Copyright © 2000 John Wiley & Sons, Ltd.     

InGaP/GaAs微波HBT器件与电路研究及应用进展

概述了近年来微波InGaP/GaAs异质结双极晶管(HBT)器件和集成电路的研究和应用现状,着重阐述了HBT器件的热设计、降低偏移电压、离子注入隔离、湿法腐蚀,以及用于电路设计的等效电路模型等关键问题.     

GaAsHBT直接耦合微波单片集成电路

叙述了基于ＧａＡｓ ＨＢＴ的直接耦合级联形式,设计制造的几种微波单片集成电路,包括２．５Ｇｂ／ｓ跨阻放大器、３ＧＨｚ可级联放大器和１０Ｇｂ／ｓ跨阻放大器的设计、制造和测试结果。     

Development of a vertical gradient freeze process for low EPD GaAs substrates

The main characteristics of low EPD 4 in semi-insulating and Si-doped conductive GaAs single crystals grown by a proprietary low thermal gradient vertical gradient freeze (VGF) technique on an industrial scale are presented.     

GaAs光电阴极智能激活研究

研制了一套基于计算机控制的GaAs光电阴极智能激活系统,该系统可在计算机控制下严格按照标准工艺对GaAs光电阴极进行智能激活,并可在线测量阴极的光谱响应曲线.利用该系统分别进行了智能激活和人工激活实验,采集了激活过程中的光电流变化曲线,分析发现,和智能激活过程相比,由于人工激活过程出现了误操作,相邻光电流峰值间的差值下降很快,Cs、O交替的次数也较少.人工激活过程中Cs、O交替6次,光电流最大值为43μA,激活后GaAs光电阴极的积分灵敏度为796μA/lm.智能激活过程中Cs、O交替9次,光电流最大值为65μA,激活后GaAs光电阴极的积分灵敏度为1100μA/lm.     

GaAs MMIC reliability studies

Three types of GaAs monolithic microwave integrated circuits (MMICs) were RF high temperature accelerated life tested to determine the median time before failure (MTBF). Life testing was performed under the d.c. bias conditions and RF input power levels the MMICs would be expected to use under actual operating conditions. the accelleration condition was to raise the base-plate temperature high enough to result in degradation in approximately 1000 hours at the highest test temperature. Because the MMICs were designed for power applications, the input signal level was large enough to cause approximately 1 dB compression. Device failure was defined as a 20 per cent decrease in output power as measured at 125°C, or room temperature when the temperature control system was turned off. Under these conditions the MTBF extrapolated to a channel temperature of 125°C varied between 8 × 10³ hours and 2 × 10⁵ hours depending on the MMIC type. The primary failure mode appeared to be surface leakage currents under the passivation layer.     

DC and AC electrical characteristics of porous GaAs/p-GaAs heterostructure

This paper reports on studying Au/porous GaAs/p⁺-GaAs heterostructure through current-voltage I (V), conductance- and capacitance-frequency dependencies (G (f) and C (f)). Diode parameters such as ideality factor and zero bias barrier energy have been calculated by using Schottky model corrected from the series resistance. The obtained ideality factor is generally high and it was explained by space charge limited current (SCLC) regime, characterised by the presence of single trapping level. A model based upon TFE tunnelling of carriers at reverse current was used to explain the non-saturation of reverse current after series resistance correction. The G (f) characteristics exhibit the presence of three frequency regions. In the first region the conductance is independent of frequency. Moreover, in the second region the AC conductance increases with increasing frequency and approximately follows ω^s dependence. These results were interpreted as the result of the transport of injected carrier via hopping mechanism involving defect. In the third region a peak conductance appeared after which the conductance decreased with increasing frequency. C (f) measurements exhibit that the capacitance behaviour is typical of material with traps. From G (f) and C (f) measurement trap density and relaxation time were calculated.     

GaAs/AIGaAs laser arrays with and without proton isolation

Abstract

Two types of GaAs/AIGaAs laser arrays, each consisting of five emitters and suitable for high power operations, have been fabricated and tested. They are easily fabricated, have high yield and deliver high power. The first array structure was fabricated using proton implantation to define the active lasing channels. Damage introduced by proton bombardment provides both electrical and optical confinement for the lasing channels. We have investigated the effect of heat treatment on the performance of these lasers and have found that the heat treated samples had a lower threshold current and higher quantum efficiency. For 400 μm long devices, with uncoated facets, we have measured a threshold current of 200 mA and a peak power of 231 mW/facet. The highest external quantum efficiency is 60%. We have also fabricated laser arrays with a simple, self‐aligned, index guided ridge waveguide structures. We have obtain a pulsed output power of up to 551 mW/facet with a quantum efficiency of 37.4%. The typical threshold current is 370 mA.     

微光管大面积GaAs负电子亲合势光电阴极(NEA)光谱特性测试与分析

结合微光管研制,对大面积GaAs与玻璃粘接制备的透射式光电阴极的光谱特性进行在线测试,并对测试结果进行了分析讨论。依据光谱特性的变化,分析了影响阴极发射性能的根源。当激活工艺稳定状态下,光谱性能差是因GaAs发射层表面氧化,受碳污染及玻璃粘接应力过大等因素造成。通过对发射层表面处理技术研究,确定了阴极制备工艺,制成了管内阴极灵敏度为1400μA/lm的NEA光电阴极和主要性能合格的微光管,使微光管研究有了突破性进展。     

GaAs超高速光调制器的研制

从理论与实验两方面研究了ＧａＡｓ定向耦合型行波光调制器，首次报导了重掺杂ｎ＾＋型薄层对电场分量相当于导体，对磁场分量相当于绝缘体这一发现；首次提出了一种具有对称宽电极的新型结构，并研制成功开关电压为８．５Ｖ，微波折射率为３．６，在３０ＧＨｚ情况下传输损耗小于１０ｄＢ／ｃｍ，根据ｓ参数测试３ｄＢ带宽达到３２ＧＨｚ的行波调制器。     

Optimisation of the epi-ready semi-insulating GaAs wafer preparation procedure

The surface quality is crucial for growth of epitaxial layers on III-V semiconductor substrates. In this work the procedures of epi-ready semi-insulating (SI) GaAs wafer preparation were developed. The atomic force microscopy (AFM), triple crystal X-ray diffraction (TCD) and X-ray photoelectron spectroscopy (XPS) were used to monitor morphology and composition of substrates with different chemical treatment history. We propose an optimised epi-ready SI GaAs wafer preparation procedure involving NH₄OH:H₂O₂:H₂O/NaOCl:H₂O₂:H₂O etching/polishing.     

NEA GaN和GaAs光电阴极激活机理对比研究

本文结合激活过程中光电流变化规律和成功激活后阴极表面模型,研究了NEA CaN和GaAs光电阴极激活机理的异同.实验表明:NEA CaN激活过程中光电流不象GaAs那样按近似指数规律的包络慢速循环上升,而是在约1min之内就可达到峰值,Cs/O激活时引入O后光电流的增长幅度不大,NEA特性仅在Cs激活时即可获得.GaAs光电阴极激活过程中O的引入是获得NEA特性的必要条件,也是真空能级下降的重要转折点,O引入后光电流幅值有较大幅度的增长.采用双偶极层模型可以解释GaN和GeAs光电阴极Cs/O激活后表面势垒的降低,但偶极层在降低表面势垒的程度方面有较大差异,CaN光电阴极降得更低.     

自组织InAs/GaAs与InGaAs/GaAs量子点生长及退火情况的比较

本文采用MBE进行InAs/GaAs与InGaAs/GaAs量子点的生长,利用RHEED进行实时监测,并利用RHEED强度振荡测量生长速率。对生长的InAs/GaAs和InGaAs/GaAs两种量子点生长过程与退火情况进行对比,观察到当RHEED衍射图像由条纹状变为网格斑点时,InAs所需要的时间远小于InGaAs;高温退火下RHEED衍射图像恢复到条纹状所需要的时间InAs比InGaAs要长。