The strain dependence of stability and diffusion barrier height of the O vacancy in Si oxide is examined using the first-principles calculation. It is found that the stability and the diffusion barrier height increase as the oxide is compressed. The analysis shows that the diffusion barrier height is determined by the Si–Si distance of the O vacancy. Based on these results, the dielectric breakdown of the gate Si oxide film in the three-dimensional structure metal-oxide-semiconductor field-effect transistor is also considered. It is suggested that the interfacial O-vacancy density increases because the interfacial oxide is subjected to compressive strain. On the other hand, the surface O-vacancy density decreases and the surface O-vacancy diffusion is promoted because the surface oxide is subjected to tensile strain. The reliability of the oxide film might be thus affected by the strain.

使用第一性原理计算来检查氧化硅中O的稳定性和扩散势垒高度对应变的依赖性。发现随着氧化物被压缩，稳定性和扩散势垒高度增加。分析表明，扩散势垒高度由O空位的Si-Si距离决定。基于这些结果，还考虑了三维结构的金属氧化物半导体场效应晶体管中的栅极Si氧化物膜的介电击穿。由于界面氧化物受到压缩应变，因此建议界面O空位密度增加。另一方面，因为表面氧化物受到拉伸应变，所以表面O-空位密度降低并且促进了表面O-空位扩散。