宽带GaAs三栅MESFET开关模型

提出一种三栅MESFET开关的模型--附加栅控开关模型,模型是根据三栅MESFET开关器件的结构,考虑了栅极对微波信号的影响,适用于MMIC开关电路的设计,具有很好的宽带微波特性.器件测试值与模型模拟值吻合较好.     

宽带GaAs MESFET开关模型

提出了一种 MESFET开关的模型——附加栅控开关模型 ,适用于 MMIC电路的设计 ,具有很好的宽带微波特性。在 0 .1～ 2 0 GHz频率范围内 ,器件测试值与模型模拟值吻合较好     

单片微波集成GaAs MESFET开关

<正>一九八0年以来,GaAs MESFET单片集成微波开关的研制工作已经取得了一些令人鼓舞的进展.与MESFET用于放大、振荡、变频等有源场合不同,在开关模型中,器件的源-漏端之间并无直流偏压,而是作为微波信号的通道,器件仅以栅偏压V_g的变化来控制开关的工作状态.当V_g=0时,器件的源-漏端之间呈现低阻抗状态,|V_g|≥V_p对应于器件的高阻抗状态.因此,MESFET作为微波开关器件实质上是一种无源应用.这种开关电路较之用PIN二极管的微波开关具有以下的优点:亚毫微秒数量级的开关时间,控制用直流耗散功率为零,双向性好,微波信号难以从栅端口泄漏,由于工艺的相容性,便于在多功能单片微波集成系统中实现高性能和小型轻量的微波开关.     

GaAs MESFET开关模型

本文提出了一种MESFET开关的模型———附加栅控开关模型 ,适用于MMIC电路的设计 ,其具有很好的宽带微波特性。开关单片的设计值与模型模拟值吻合较好。     

1～18GHz GaAs微波单片集成电调衰减器

<正> 目前用于微波控制电路的半导体器件主要是PIN管,然而,随着微波器件和微波技术的改进,微波部件不仅应有较宽的频率特性,同时还需具有体积小、重量轻、成本低的特点。近几年来,随着GaAs MESFET性能的不断提高、成本明显降低,使MESFET在微波控制电路方面具有令人振奋的应用前景,且已取得了许多可喜的成果。同样,在属于微波控制电路的衰减器方面,现已研究出GaAs MESFET数字控制和模拟控制单片微波衰减器。 MESFET用于衰减工作模型时,与放大、振荡,变频等场合不同,器件的源-漏之间并无直流偏压,而是作为微波信号的通道,器件仅以改变栅偏压Vg来控制器件的阻抗变化,使MESFET作为电调可变电阻。当栅偏压Vg=0时,栅下空间电荷层薄,沟道是开通的,器件的源-漏之间呈低阻抗状态;当|Vg|大于夹断电压|Vg|时,栅下沟道已全部耗尽,构成     

GaAs双栅MESFET的设计与性能分析

本文将双栅MESFET模拟成两个级联的单栅MESFET,用三端信号流通图来分析它的性能特征.并将双栅MESFET当作一个短的行波管来说明其工作原理的物理本质.可以看出,它是一种在微波领域中有着广泛用途的多功能器件.本文还讨论了GaAs双栅MESFET的设计.采用金属剥离工艺制作的双指状、深凹糟1微米栅的双栅MESFET,在4千兆赫下相关增益为20分贝,噪声系数为1.9分贝,在8千兆赫下相关增益为18分贝,噪声系数为2.8分贝.     

高温正向栅电流下Ti/Pt/Au栅SiC MESFET的栅退化机理

SiC MESFET器件的性能强烈依赖于栅肖特基结的特性,而栅肖特基接触的稳定性直接影响其可靠性.针对SiC MESFET器件在微波频率的应用中射频过驱动导致高栅电流密度的现象,设计了两种栅极大电流的条件,观察栅肖特基接触和器件特性的变化,并通过对试验数据的分析,确定了栅的寄生并联电阻的缓慢退化是导致栅肖特基结和器件特性退化,甚至器件烧毁失效的主要原因.     

微波功率SiC MESFET小信号等效电路建模研究

在传统GaAs MESFET器件小信号模型基础上提出一种更适合SiC MESFET器件的小信号等效电路模型.该模型在引入了与栅压相关的输入电导后,明显改善了S11的拟合精度.提出直接利用cold FET反向栅压偏置下的S参数,通过曲线拟合和外插技术提取SiC MESFET小信号等效电路寄生参数的方法.该模型应用于国内SiCMESFET工艺线,在O.5～18GHz范围内S参数的仿真值和实测值非常吻合.     

8.9W/mm高功率密度SiC MESFET器件研制

基于自主研发的碳化硅(SiC)材料外延技术,优化了材料各层结构及参数,减小了Al记忆效应,最终得到了高质量SiC外延片。采用自主研发成熟的SiC MESFET工艺平台,制作了多凹栅器件结构,优化了凹槽尺寸,采用细栅制作技术完成了栅电极制作,最终得到了不同栅宽的SiC MESFET芯片。突破了大栅宽芯片流片、封装及大功率脉冲测试技术,研制成功了微波功率特性良好的MESFET器件。微波测试结果表明,在2 GHz脉冲条件下,0.25 mm栅宽器件,输出功率密度达到8.96 W/mm,功率附加效率达到30%。单胞20 mm大栅宽器件,3.4 GHz脉冲条件下,功率输出达到94 W,功率附加效率达到22.4%。     

采用离子注入N~+层和质子隔离的12GHz 200mW功率GaAs MESFET

本文报导了采用质子隔离和Si~+离子注入N~+接触层技术,提高了功率GaAa MESFET的微波性能和可靠性.已经制成栅长1μm,总栅宽600μm的GaAs功率MESFET,12GHz下最大输出功率210mW,经严格考核表明器件具有较高的可靠性.     

GaAs MESFET直流解析模型

根据FET沟道区电场分布的特点,用电子速场特性的分段近似提出了一种新的GaAs MESFET直流解析模型。本文提出的模型可用以计算高夹断电压和低夹断电压GaAs MESFET的直流特性,比完全速度饱和模型及平方律模型更为精确。     

Principles of large-signal MESFET operation

The large-signal RF operating principles of MESFET amplifiers are investigated using a circuit simulator that incorporates a physics based MESFET model which has been augmented with a new gate breakdown model. It is demonstrated that the main saturating mechanisms of the MESFET under large-signal RF operation are forward and reverse conduction of the gate electrode. Maximized RF performance of MESFET amplifiers is obtained by optimally positioning the dynamic load line relative to the RF-IV plane. The position of the dynamic V-I characteristic is determined by device breakdown, bias, and circuit tuning conditions     

大信号设计GaAs MESFET功率合成

利用ＧａＡｓＭＥＳＦＥＴ功率特性的线性化模型，求出ＧａＡｓＭＥＳＦＥＴ近似最佳功率负载阻抗，为利用谐波平衡法计算提供初值。然后，使用自行研制的谐波平衡分析软件包，进行ＧａＡｓＭＥＳＦＥＴ大信号模型参数的提取和非线性电路模拟计算。将两只总栅宽为９．６ｍｍ的ＧａＡｓＭＥＳＦＥＴ管芯，利用内匹配功率合成技术，在Ｃ波段（５．５～５．８ＧＨＺ）制成１ｄＢ压缩功率大于８Ｗ，典型功率增益９ｄＢ的ＧａＡｓＭＥＳＦＥＴ内匹配功率管。     

SiCOI MESFET的特性分析

提出了一种新的器件结构-SiCOI结构,即硅衬底上外延SiC制造MESFET器件,并建立了SiCOI MESFET器件结构与模型。使用ISE-TCAD二维器件仿真软件,对SiCOI MESFET的电学特性进行模拟分析。结果表明,通过调整器件结构参数,例如门极栅长、有源层掺杂浓度、有源区厚度等,对器件转移特性、输出特性有较大影响。同时,还对SiCOI MESFET器件的击穿特性进行了模拟。这些电学特性数据为进一步设计及优化SiCOI MESFET器件提供理论基础。     

A capacitance model for GaAs MESFETs

A capacitance model for a GaAs MESFET suitable for implementation in the circuit analysis program SPICE is presented. The model consists of nonlinear capacitances that are a function of two voltages. Such a model gives rise to ordinary nonlinear capacitances and transcapacitances. The placement of these elements in the Y matrix is shown. The empirical equations for the gate charge of a GaAs MESFET given provide an accurate SPICE model for the gate charge and capacitances of a MESFET. A comparison of measured capacitance values with the modeled values gives close enough agreement for circuit simulation purposes     

Full band Monte Carlo simulation of zincblende GaN MESFET'sincluding realistic impact ionization rates

In this paper, we present the first theoretical study of the breakdown properties of zincblende phase GaN MESFET devices. The calculations are made using a full band, ensemble Monte Carlo simulation that includes a numerical formulation of the impact ionization transition rates. The breakdown voltage, transconductance and cutoff frequency are calculated for the GaN MESFET under two different conditions, with and without semiconductor-oxide interface states. Uniform surface depletion regions model the effect of the interface states. It is found that the breakdown voltage of the zincblende GaN MESFET is less dependent upon the surface depletion conditions than a corresponding GaAs MESFET. It is also found that the drain current increases more gradually with increasing drain-source voltage at the onset of breakdown and that the breakdown voltage of the zincblende GaN MESFET is predicted to be several times larger than that of a comparable GaAs MESFET. The maximum current gain cutoff frequency of a 0.1 μm gate length GaN MESFET is calculated to be 230 and 220 GHz, for the non-surface-depleted and the surface depleted devices respectively     

Distributed scaling approach of MESFETs and its comparison with thelumped-element approach

An appropriate scaling procedure is described for large four-finger MESFET cells with experimental verification. A comparison is presented between lumped and distributed modeling approaches. The scalability of elements in the equivalent circuit model of a MESFET is discussed     

Compact modeling of a PD SOI MESFET for wide temperature designs

A compact model for the partially depleted (PD) silicon-on-insulator (SOI) metal semiconductor field effect transistor (MESFET) is presented. The absence of a gate-oxide makes the SOI MESFET extremely robust, able to withstand high voltages, and useful for extreme environment electronics. These devices have been fabricated using a standard SOI CMOS process. In contrast to SOI MOSFETs and GaAs MESFETs, the source-substrate voltage has a significant impact on the channel current. In this work a model has been developed that includes the effect of the buried oxide on the performance of the MESFET. The model has been verified for a wide temperature range of −180 to 150 °C. A behavioral model has been included to model the breakdown voltage. The core DC and RF models have been adapted from the commercially available Triquint's Own Model (TOM3) MESFET model. Building from the TOM3 model, a measurement-based approach is used to develop a four-terminal compact model using Verilog-A. The charge-based approach, using S-parameter measurements was used to develop the capacitance model. We also present a voltage reference circuit using two MESFET transistors to verify the model and explore wide temperature range circuit applications.