Analysis of Current Gain in Al0. 3Ga0. 22In0. 48P/GaAs HBT at High Temperature
高温Al_(0.3)Ga_(0.22)In_(0.48)P/GaAsHBT电流增益的计算分析

An analytical model of current transport process in the Al 0.3 Ga 0.22 In 0.48 P/GaAs HBT (Heterojunction Bipolar Transistor) is presented.Using material parameters extracted from the experiments,we have simulated change of current gain in HBT with respect to temperatures.As temperature rises,current gains suffer large reduction in the low current region,but remain relatively stable in the high current region.Simulation shows that current drop at low current densities is due to the sharp increase of recombination current with temperature in the space charge region of the e\|b junction,but at high current densities current gains decrease less that 10% till 723K.The maximum operation temperature can reach 848K.The theoretical method used in this paper has taken the recombination current in space charge region fully into account,thus can provide better approximation to the experimental results.Our calculation can provide some insight into the material fabrication for high performance HBT.