SiGe合金半导体中自间隙缺陷和两种碳相关缺陷的计算研究

Calculation of Si-interstitial Defect and Two Carbon-Related Defects in SiGe Alloy Semiconductors

采用从头计算(abinitio)的方法对比研究了Si1-xGex合金半导体材料中W缺陷、CiCs缺陷和CiOi缺陷的性质。在Si1-xGex合金中,Ge原子不能与缺陷核心的C原子和O原子直接成键,但可能与W缺陷核心的间隙Si原子相连。在含CiOi缺陷的晶胞中,Ge原子倾向于取代沿[110]伸长方向的Si原子。随着合金中Ge含量的升高,W缺陷的形成能不断增加,结构稳定性逐渐降低。与W缺陷不同的是,CiCs缺陷和CiOi缺陷在不同Ge含量的Si1-xGex合金中形成能变化较小,变化幅度在0.15eV以内,理论研究结果与前人的实验结果相吻合。

The characteristics of W defect, CiCs and CiOi defects in the Si1-xGex alloys were investigated using the ab initio method. In the Si1-xGex alloys, a direct Ge-C or Ge-O bond was unlikely to be formed, but the direct connection of Si and Ge in W center could not be excluded. In the Si1-x Gex alloy containing CiOi defect, Ge atom was apt to substitute the Si atom in the [ 110 ] tensile direction. With the increase of Ge content in the Si1-xGex alloys, ergy of W defect increased rapidly, the formation entherefore the stability of W defect decreased. Different from W defect, the formation energy of CiCs and CiOi defects changed a little in the alloys with various Ge content, smaller than 0.15 eV. The theoretical calculation results were consistent with experimental results.