考虑自热效应的重掺杂AlGaAs/GaAs HBT电流特性分析

The Analysis of Currents of AlGaAs/GaAs HBT with Heavy Doping of the Base Including Self-heating Effects

重掺杂使导带、价带带边同时发生了收缩 ,从而产生能带变窄效应 ( BGN)。对于因重掺杂 NPN突变 Al Ga As/Ga As HBT,而引起 BGN导带和价带突变界面势垒形状及高度都发生改变结果 ,以致对电流输出特性产生重要的影响。本文基于 Jain-Roulston禁带收缩模型及热场发射——扩散载流子输运机制 ,对考虑自热效应下的重掺杂 Al Ga As/Ga-As HBT电流特性进行了深入的研究。通过与其它计算程序常用的几种 BGN模型比较得出 :为了更好描述电流传输 ,利用 Jain-Roulston的 BGN模型 ,考虑导带。

Heavy impurity doping makes the conduction and valence bands shift, and brings about the so-called Band Gap Narrowing(BGN). Due to BGN, the form and height of energy barriers in abrupt HBT is disturbed, which change the values of the currents flowing through its interfaces. In this work, the real bandgap narrowing is distributed between the conduction and valence bands according to Jain-Roulston model, and its effects on the output of the currents of AlGaAs/GaAs HBT including self-heating effects is analysis. This analysis is carried out through so-called Thermionic-Field-Diffusion model which combines the drift-diffusion transport in the bulk of the transistor with the thermionic emission and tunneling at the base-emitter interface. By comparison, it can be concluded that using more accurate bandgap modeling is important for a better description of the currents.