The effect of compressive biaxial stress on vacancy clustering in thin Si-Ge layers

The paper presents the results of the study of elastic interaction and clustering of vacancies in Si75Ge25 and Si50Ge50 alloys under plane stress loading, as appropriate to thin SiGe layers grown coherently on top of a bulk silicon substrate. The first-principles calculation of the total energies of vacancy-vacancy and vacancy-Ge atom pairs predicts that the energy of a vacancy pair is sensitive to the pair orientation with respect to the principal crystalline axes. Lattice kinetic Monte-Carlo simulation of vacancy annealing demonstrates that such orientational dependence of vacancy interaction noticeably influences both the kinetics of vacancy annealing at elevated temperatures and the shape of the resulting vacancy clusters. (C) 2006 Elsevier Ltd. All rights reserved.