Theory of the AlN/SiC(101¯0) interface

We report first-principles calculations of surface and interface energies for AlN(101¯0) and SiC(101¯0). On the basis of our calculations we predict the atomic structure of the interface. We find that there is an interaction between the surface and the interface mediated by their respective strain fields. Consequently, the formation energy of very thin films of AlN on SiC deviates from that expected on the basis of a simple model in which E_film=σ_film-σ_sub+E_int. Our results indicate that AlN films of thickness 3–4 bilayers will wet the SiC surface.