An ab initio investigation of the electronic and structural properties of the intrinsic stacking fault in SixGe1–x was presented. A study was also made of the interaction of vacancies with the intrinsic stacking fault. The formation energy, per unit area, of the intrinsic stacking fault was 2.1, 3.0 and 3.3meV/Å2, in pure Si, Si0.5Ge0.5 and pure Ge, respectively. It was also shown that the intrinsic stacking fault did not locally alter the randomness of the of the Si0.5Ge0.5 alloy. As far as the interaction of vacancies with the intrinsic stacking fault was concerned, it was shown that the intrinsic stacking fault acted as a sink to vacancies in Ge and in Si0.5Ge0.5, similarly to what was known to happen in Si. The formation of vacancies close to the intrinsic stacking fault was energetically favorable, by about 0.2eV, in comparison with the formation of vacancies in bulk-like environments. Similarly to what happens in bulk SixGe1–x, the formation energy of the vacancies near the intrinsic stacking fault depended strongly on the number of Si and Ge atoms in its nearest neighborhood.

Theoretical Investigation of Extended Defects and their Interactions with Vacancies in SixGe1–x. R.H.Miwa, P.Venezuela, A.Fazzio: Physical Review B, 2003, 67[20], 205317 (5pp)