The energetics and migration of B in ordered Si-epitaxial Si0.5Ge0.5, were studied by using first-principles calculations. Particular attention was paid to the interstitial-mediated mechanism that had been associated with B transient enhanced diffusion in Si. The temperature dependence of the migration length of a B-interstitial complex was deduced from migration barriers and dissociation energies. The migration length was similar to that in Si; due to the preference of B for Si-like equilibrium sites and diffusion paths. In Si epistrained SiGe, the solubility was enhanced by 2 orders of magnitude and, in free-standing SiGe, by one order of magnitude.

Energetics of Transient Enhanced Diffusion of Boron in Ge and SiGe. P.Delugas, V.Fiorentini: Physical Review B, 2004, 69[8], 085203 (5pp)