A new mechanism of elastic energy relaxation in heteroepitaxy of monocrystalline films: Interaction of point defects and dilatation dipoles

Abstract

A new method for growing a low-defect elastic-stress-free silicon carbide film on silicon substrates is theoretically developed and experimentally implemented. In this method, the relaxation of inevitable elastic stresses is attained by an essentially new mechanism, namely, by dilatation dipoles (stable complexes consisting of attracting dilatation centers) formed by a carbon atom in interstitial position and a silicon vacancy. The tensor Green function for elastic-anisotropic media is used to obtain the dependence of the point defect interaction energy on their mutual crystallographic location in silicon. It is shown that the situation where the dilatation dipole is perpendicular to the plane (111) is most efficient for a cubic crystal. In this case, practically the whole elastic energy of the film dilatation can be relaxed only at the expense of dipoles, and this must produce a high quality of silicon carbide films.