First-principles methods were used to determine how Si diffused in the layered silicide, ErSi2−x. The Si diffusion was found to be extraordinarily anisotropic, with the migration barrier associated with Si diffusion across Er planes being nearly 4 times larger than that within Si planes. The activation energy for in-plane diffusion of Si decreased by 20% when ErSi2−x was grown hetero-epitaxially onto Si(001); as a result of epitaxial strain. This effect was associated with the manner in which strain modified the formation energy of the diffusing defect and changed the energy landscape for diffusion. The results were consistent with experimental observations of defect formation in hetero-epitaxial ErSi2−x films on Si(001).

Mechanisms of Silicon Diffusion in Erbium Silicide. G.W.Peng, Y.P.Feng, A.C.H.Huan, M.Bouville, D.Z.Chi, D.J.Srolovitz: Physical Review B, 2007, 75[12], 125319 (5pp)