重掺B对应变SiGe材料能带结构的影响

Band gap Narrowing in heavily B doped Si_(1-x)Ge_x strained layers

硅锗异质结双极晶体管(SiGeHBT)一般以重掺硼(B)的应变SiGe层作为基区.精确表征SiGe材料能带结构对SiGeHBT的设计具有重要的意义.在应变SiGe材料中,B的重掺杂一方面会因为重掺杂效应使带隙收缩,另一方面,B的引入还会部分补偿Ge引起的应变,从而改变应变引起的带隙变化.在重掺B的应变SiGe能带结构研究中,采用半经验方法,考虑了B的应变补偿作用对能带的影响,对Jain-Roulston模型进行修正,并分析了重掺杂引起的带隙收缩在导带和价带的分布.

This paper presents a comprehensive study of the effect of heavy B doping and strain in Si 1-xGex strained layers.On the one hand,bandgap narrowing（BGN）will be generated due to the heavy doping,on the other hand,the dopant boron causes shrinkage in the lattice constant of SiGe materials,thus will compensate for part of the strain.Taking the strain compensation of B into account for the first time and uesing the with semi-empirical method,the Jain-Roulston model is modified.And the real BGN distributed between the conduction and valence bands is calculated,which is important for the accurate design of SiGe HBTs.