Experimental data indicated that B diffused very differently in Ge than in Si. To examine the kinetics of B diffusion, density functional calculations were performed on a variety of B diffusion mechanisms, including interstitial and vacancy-mediated paths, as well as a correlated exchange mechanism. It was found that, although vacancy and correlated exchange mechanisms possessed high diffusion barriers, comparable with experiment, the barrier for interstitial-mediated diffusion lay at around 3.8eV and was similar to those found for B diffusion in Si. This estimate was well below the experimental activation energy. The difference was attributed to the failure of the theory to include the effect of electronic excitations.Ab initio Investigation of Boron Diffusion Paths in Germanium. C.Janke, R.Jones, S.Öberg, P.R.Briddon: Physical Review B, 2008, 77[7], 075208 (6pp)

Table 3

Diffusivity of Sb in Ge