Density functional theory calculations and molecular dynamics simulations were used to decouple the influence of strain and the effect of Ge content upon the diffusivity of intrinsic defects and group-V dopants in strained Si and SiGe. Vacancy diffusivities increased with increasing Ge content. In contrast, interstitial diffusivities in SiGe remained roughly constant until the Ge content reached 25% and then decreased. Tensile strain increased interstitial-assisted dopant diffusivity and decreased vacancy-assisted diffusivity. The Ge reduced interstitial diffusivity in a manner controlled by dopant V size but assisted vacancy diffusivity (lowering formation energies by ~0.2eV).

Effects of Ge Content on the Diffusion of Group-V Dopants in SiGe Alloys. M.Haran, J.A.Catherwood, P.Clancy: Applied Physics Letters, 2006, 88[17], 173502 (3pp)