应变Si/(001)Si1-xGex能带结构模型

应变Si材料的能带结构是研究设计高速/高性能器件和电路的理论基础。采用结合形变势理论的K.P微扰法建立了(001)面弛豫Si1-xGex衬底上生长的张应变Si的能带结构模型。结果表明:[001]、[001]方向能谷构成了张应变Si导带带边,其能量值随Ge组分的增加而变小;导带劈裂能与Ge组分成线性关系;价带三个带边能级都随Ge组分的增加而增加,而且Ge组分越高价带带边劈裂能值越大;禁带宽度随着Ge组分的增加而变小。该模型可获得量化的数据,对器件研究设计可提供有价值的参考。

Band Structure Models of Strained Si/(001)Si_(1-x)Ge_x

The band structure of strained Si is the theoretical basis for the design of the high-speed and high-performance devices and circuits. The band structure models of strained Si on (001) relaxed Si1-xGex were presented using K.P perturbation method coupled with deformation potential theory. The results show that the [001]、[001]valleys constitute the conduction band (CB) edge,which moves down in electron energy as Ge fraction (x) increases,and the CB splitting energy is in direct proportion to x as well as all the valence band (VB) edges move up in electron energy as x increases. In addition,the decrease in the indirect bandgap and the increase in the VB edge splitting energy with increasing x were found. The quantitative data from the models supply valuable references to the devices design.