Role of surface effects on silicon carbide polytype stability

We investigated with ab initio calculations the energetics of the most common silicon carbide (SiC) polytypes. We considered the (0001) Si face and the (0001¯) C face of 3C-, 6H-, 4H- and 2H–SiC. Our investigation reveals that the energy differences among SiC polytypes are enhanced at the surface with respect to the bulk. We discuss the relevant role played by the surface for the crystal growth of SiC.

► We investigated the energetics of some silicon carbide polytypes.
► Bulk energy differences are too low to explain the polytype stability.
► However, surface energetics strongly influence the polytype selection.
► This study contributes to explain growth instabilities like step bunching and polytype mixing.