应变p型Si_(1-x)Ge_x层中载流子冻析

Carrier Freeze-Out in Strained p-Si_(1-x)Ge_x Layers

本文用解析的方法研究了应变P型Si_(1-x)Gex层中载流子冻析现象．研究发现，用Si归一化的Si(1-x)Gex价带有效态密度，随x的增加而减小，而且温度T越低，随Ge组份x的增加而减少的速度越快与Si相比，常温下Ge组份x几乎对电离杂质浓度没有什么影响，而在低温下，随Ge组份x的增加，电离杂质浓度随之增加，载流子冻析减弱，这对低温工作的Si(1-x)Gex器件有利．

The caaccer freeze-out in strained p-Si1--Gex layers is studied analytically. It is found that as the Ge fraction increases, the valences effective densities of states(Nv)SiGe/(Nv)Si normlized bythat in Si decreases, furthermore, as the temperature beecomes lower, the decrease in (Nv)SiGe/(Nv)Si becomes more rapid. It is also shown that as the Ge fraction increases, although it has little effect on theionized doping concentration at room temperature, the ionias doping concentration inereases at low temperatures compared with that in Si. This implies that caaccer freeze-out is mitigated at low temperatures,which is beneficial to the operation of Sil-Gex-based devices at low temperatures.