First principles study of the decomposition processes of AlN in a hydrogen atmosphere

The growth of AlN films by the hydrogen vapor phase epitaxy method is generally carried out at a high temperature over a hydrogen atmosphere. The difficulties concerned with the decomposition processes on the surface during the film growth result in necessity of computer modelling of that processes. First principles calculations of the decomposition processes of AlN in a hydrogen atmosphere are reported. The mechanism of desorption of atoms from the surface was deter-mined. Al atoms desorb as AlH from (0001) surface and as Al from (000-1) surface of AlN. And N atoms desorb as NH3 from (0001) surface and as NH from (000-1) surface of AlN. The desorption of Al atoms is a rate limiting reaction. The calculation results correspond well with the experimental date published earlier. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.