Simulation of High Speed AlGaAs/GaAs Heterojunction Bipolar Transistors

这是马萨诸塞大学关于先进半导体设备的计算机建模研究计划的继续。一个具体的目标是扩展用于高速和/或高频应用的异质结半导体器件的数值建模的最新技术。在过去的12年里，我们在实验室对从大型VMOS功率晶体管到亚微米可渗透基区晶体管(PBT)的各种半导体器件进行了建模。鉴于最近人们对高速异质结晶体管，如高电子迁移率晶体管(HEMT)和异质结双极晶体管(HBT)的兴趣，我们的研究自然会扩展到涉及异质结的半导体器件的建模。在时间允许的情况下，重点将放在AlGaAs/GaAs系统上，但InGaP/GaAs异质结和InGaAs/GaAs应变层异质结也可能包括在内。需要模拟的基本异质结结构是垂直器件，如HBT。将研究这些器件的梯度基区中的热载流子输运。将进行暂态和小信号交流漂移-扩散分析，以准确确定单位电流增益截止频率。

This is a continuation of the research program at the University of Massachusetts on the computer modeling of advanced semiconductor devices. A specific objective is to extend the state-of-the-art of the numerical modeling of heterojunction semiconductor devices for high speed and/or high frequency applications. Over the past twelve years, we have modeled semiconductor devices ranging from large VMOS power transistors to submicron permeable base transistors (PBT) in our laboratory. In view of recent interest in high speed heterojunction transistors such as HEMT (high electron mobility transistors) and HBT (heterojunction bipolar transistors), it is natural to extend our research to the modeling of semiconductor devices involving heterojunctions. Focus will be placed on the AlGaAs/GaAs system but the InGaP/GaAs heterojunction and the InGaAs/GaAs strained-layer heterojunction may be included as well, time permitting. The basic heterojunction GaAs structures to be modeled are vertical devices such as HBTs. Hot carrier transport in the graded base region of these devices will be investigated. Both transient and small-signal ac drift-diffusion analysis will be performed to accurately determine the unit-current gain cutoff frequency.