First-principles calculations were made of internal interfaces in Si and SiC. Density-functional calculations within the local-density approximation and the pseudopotential-plane-wave approach were performed in order to understand the effect of such 2-dimensional defects upon the electronic properties. A study was made of the interface between the 3C and 2H polytypes along the [111]/[00▪1] direction. A {221} tilt boundary between two cubic crystals, which was often observed in chemical vapor deposited films of SiC, was examined. The interface corresponding to a {115}/{3¯3▪2} plane between the 3C and 2H phases was also considered. It was especially interesting since it could contribute to a quantum-wire like inclusion of cubic SiC in hexagonal SiC. Whereas the {111}/{00▪1} interface introduced only shallow states into the bulk fundamental gaps, the particular bond-ring topology of the {221} and {115}/{3¯3▪2} interfaces gave rise to a variety of states; even resulting in a metallic behavior in the latter case for SiC.

Ab initio Study of Structural and Electronic Properties of Planar Defects in Si and SiC. C.Raffy, J.Furthmüller, J.M.Wagner, F.Bechstedt: Physical Review B, 2004, 70[19], 195344 (12pp)