Damage effect and mechanism of the GaAs pseudomorphic high electron mobility transistor induced by the electromagnetic pulse

The damage effect and mechanism of the electromagnetic pulse(EMP) on the GaAs pseudomorphic high electron mobility transistor(PHEMT) are investigated in this paper. By using the device simulation software, the distributions and variations of the electric field, the current density and the temperature are analyzed. The simulation results show that there are three physical effects, i.e., the forward-biased effect of the gate Schottky junction, the avalanche breakdown, and the thermal breakdown of the barrier layer, which influence the device current in the damage process. It is found that the damage position of the device changes with the amplitude of the step voltage pulse. The damage appears under the gate near the drain when the amplitude of the pulse is low, and it also occurs under the gate near the source when the amplitude is sufficiently high, which is consistent with the experimental results.     

A Very Low-Noise Integrated 3MM-Wave Schottky Diode Mixer and PHEMT IF Amplifier

An integrated 3mm-wave Schottky diode mixer and pseudomorphic high-electron-mobility transistor (PHEMT) IF amplifier with record noise performance at room temperature is described. The design has shown the room-temperature double-sideband (DSB) receiver noise temperature T_R^DSB of 190 K at 100 GHz due to a very low conversion loss in the full-height waveguide mixer and an ultra-low noise of the PHEMT IF amplifier. The receiver noise temperature has been reduced by a factor of 1.5 in comparison with the best previously reported 3mm-wave Schottky diode mixer receiver.     

High Doping Density Schottky Diodes in the 3MM Wavelength Cryogenic Heterodyne Receiver

The paper describes a 3mm cryogenic mixer receiver using high doping density (“room-temperature”) Schottky diodes. The measured equivalent noise temperature T_eq of the diodes is 109 K at 20 K, which is much higher than the T_eq of the low doping density (“cryogenic”) diodes. In spite of this, the double-sideband (DSB) noise temperature of the cryogenic receiver developed is 55 K at 110 GHz, owing to the low conversion loss of the mixer and ultra-low noise of the PHEMT IF amplifier. This is the lowest noise temperature ever reported for a Schottky diode mixer receiver. The results obtained are useful for the development of submm receivers in which high doping density Schottky diodes are used.     

外界条件在电磁脉冲对GaAs赝高电子迁移率晶体管损伤过程中的影响

结合器件仿真软件Sentaurus TCAD,建立了GaAs赝高电子迁移率晶体管器件的电磁脉冲损伤模型.基于此模型,从信号参数和外接电阻两个方面出发讨论了外界条件对器件电磁脉冲损伤效应的影响.结果表明,信号参数的改变能够显著影响器件的损伤时间:信号幅度通过改变器件的吸收能量速度来影响器件的损伤效应,其与器件损伤时间成反比;信号上升时间的改变能够提前或延迟器件的击穿点,其与器件损伤时间成正比.器件外接电阻能够减弱器件的电流沟道,进而延缓器件的损伤进程,且源极外接电阻的影响更加明显.     

An Improved Pinchoff Equivalent Circuit Model for Determining PHEMT Model Parameters for Millimeterwave Application

An improved equivalent circuit model under pinchoff condition for extracting parasitic model parameters for Double Heterojunction -doped PHEMTs is presented. Good prediction for S parameters and noise performance are obtained up to 40GHz. A modified parameter extraction technique based on this new model was use to determine a PHEMT equivalent circuit model. Signification improvements of the accuracy of S parameters are obtained by using the new pinchoff model.     

An Improved On-Wafer Measurement Method for PHEMT Modeling for Millimeter Wave Application

An improved on-wafer measurement method by using coaxial calibration instead of on-wafer calibration for PHEMT modeling is proposed in this paper. The advantage is that S-parameters of PHEMT device can be measured on wafer without impedance standard substrate (ISS) after the S-parameters of the microprobes have been determined. Excellent agreement is obtained between on-wafer calibration measurement and coaxial calibration measurements, respectively.     

An Approach for Extracting Small-Signal Equivalent Circuit of Double Heterojunction δ-Doped PHEMTs for Millimeter Wave Applications

Pseudomorphic high electron mobility transistors (PHEMTs) are very important in millimeterwave application. A simple and accurate method for extracting small-signal equivalent curcuit for Double Heterojunction -doped PHEMT valid up to 40GHz is presented. First, the parasitic parameters of the equivalent circuit are determined using pinch off PHEMT except for PAD capacitances. The initial intrinsic elements are then determined by conventional analytical method. Advanced Design System is then used to optimize the whole model parameters with very small dispersion of initial values. Good agreement is obtained between simulation results and measured results for a 0.25um DH PHEMT.     

AlGaAs/InGaAs PHEMT栅电流参数退化模型研究

为定量研究在PHEMT栅电流退化过程中, 不同失效机理对应的参数退化时间常数及退化比例, 本文基于退化过程中物理化学反应中反应量浓度与反应速率的关系, 建立了PHEMT栅电流参数退化模型. 利用在线实验的方法获得PHEMT电学参数的退化规律, 分析参数随时间的退化规律, 得到不同时间段内影响栅电流退化的失效机理, 并基于栅电流参数退化模型, 得到了不同的失效机理对应的参数退化时间常数及退化比例. 关键词： PHEMT 栅电流 肖特基接触 退化模型     

An Approach for Determining PHEMT Small-Signal Circuit Model Parameters Up to 110GHz

This paper describes a method to determine the small-signal equivalent circuit model elements for Double Heterojunction δ-doped PHEMTs, which combines the analytical approach and empirical optimization procedure. The PAD capacitances are determined by measuring an open structure which consists of only the pads. Intrinsic elements determined by a conventional analytical parameter transformation technique are described as function of extrinsic elements. Variation ranges of extrinsic elements for optimization are obtained by using coldfet method. An excellent fit between measured and simulated S-parameters in the frequency range of 2-110GHz is obtained for 2×100um gate width (number of gate fingers × unit gate width) DH PHEMT.     

Analysis of the damage threshold of the GaAs pseudomorphic high electron mobility transistor induced by the electromagnetic pulse

An electromagnetic pulse(EMP)-induced damage model based on the internal damage mechanism of the Ga As pseudomorphic high electron mobility transistor(PHEMT) is established in this paper. With this model, the relationships among the damage power, damage energy, pulse width and signal amplitude are investigated. Simulation results show that the pulse width index from the damage power formula obtained here is higher than that from the empirical formula due to the hotspot transferring in the damage process of the device. It is observed that the damage energy is not a constant, which decreases with the signal amplitude increasing, and then changes little when the signal amplitude reaches up to a certain level.