具有超高掺杂基区的GaAs赝HBT分析

Analysis on GaAs Pseudo-HBTs with Ultrahigh Doped Base

超高掺杂GaAs具有明显的禁带变窄(BGN)效应,因此采用超高掺杂基区的GaAs同质晶体管也可获得HBT的效果.故称之为赝HBT(p—HBT)。本文根据实验结果讨论了超高掺杂情况下GaAs的BGN效应及其对有效本征载流子浓度的影响,并对np^+n型结构GaAs p—HBT的发射极注入效率和共发射极电流增益进行了理论分析。结果表明,当基区掺杂浓度高于1×10^(20)/cm^3时可以获得较好的器件特性。

Ultrahigh doped GaAs has considerable bandgap narrowing (BGN) effect, so that GaAs homo-BTs with ultrahigh doped base act as HBT and can be called as pseudo -HBT. In this paper,the BGN effect and its influence on the effective intrinsic carrier concentration of GaAs under ultrahigh doping were discussed based on the experimental results reported in literature,and the emitter injection efficiency and common-emitter de current gain of np+n GaAs p-HBT's were analysed theoretically.It was shown that the devices can possess higher and can be applied for high frequency amplification when the base region is doped higher than 1X1020/cm3.