单载流子传输双异质结光敏晶体管频率特性分析

摘要

To relieve the contradiction between phototransistor response and its working speed, the influences of photo-generated carriers in UTC-DHPT on the junction capacitances of emitter junction and collector junction were discussed in detail and then the high frequency modeling of UTC-DHPT was built in this paper. Based on the proposed modeling, the optical gain and optical characteristic frequency of UTC-DHPT were analyzed under three different working modes, namely DHBT working mode, 2T two-terminal working mode with only optical base biasing and 3 T three-terminal working mode with hybrid optical and electrical base biasing. The results show that UTC-DHPT have better frequency response than traditional SHPT, and UTC-DHPT can provide high responsivity and high response speed simultaneously at 3T working mode.%为了缓解光敏晶体管探测器在响应度和响应速度优化时存在的矛盾并提高响应度和响应速度,分析了单载流子传输( uni-travelling-carrier,UTC)双异质结光敏晶体管( double hetero-junction phototransistor,DHPT)中光生载流子对发射结结电容和集电结结电容的影响,建立了UTC-DHPT的频率特性模型. 基于所建模型,研究了UTC-DHPT在电学晶体管工作状态( double hetero-junction transistor, DHBT)、基极光偏置的二端工作模式( two terminal, 2T)和基极光电混合偏置的三端工作模式( three terminal, 3T)的光电流增益和光学特征频率. 结果表明:UTC-DHPT比传统的単异质结光敏晶体管( single hetero-junction phototransistor,SHPT)有更好的频率特性,3T工作模式下的UTC-DHPT可以同时提供高响应度和高响应速度.