First-principles study of beta-AlN thin films on beta-SiC(001)

We have investigated the initial stages of formation of cubic AlN films on SiC(001) by studying the energetics of possible structures. We have conside red 1X1 and p(4X1) surface reconstructions for the films, and we have allow ed for different interface arrangements including atomic mixing. The result s of our first-principles calculations reveal that, in N-rich conditions, n o two-dimensional film structure is stable. However, in Al-rich conditions, it is possible to stabilize a thick wetting layer of cubic AlN provided th e proper interface mixing is achieved. The most stable AlN film exhibits a p(4X1) surface reconstruction. (C) 1999 American Institute of Physics. [S00 03-6951(99)03915-7].