Kinetic Monte Carlo simulations for AlN and AlGaN epitaxial growth on AlN

With increasing availability of AlN substrates, growth of AlN and AlGaN epitaxial layers on AlN(0001) has become a subject of extended experimental investigations. For a deeper understanding of the growth process, we developed a kinetic Monte Carlo (KMC) model for the adsorption, desorption, and diffusion on a stepped Al(001) surface under MOVPE conditions. Nitrogen is provided via ammonia and we assumed that the surface is covered by N in a 2 × 2 N reconstruction. This reconstruction could be obtained in our calculations for a flat surface. We performed several runs for a vicinal AlN(0001) surface with a miscut of 3° in m-direction [11¯00] direction. The results are analysed in detail both for AlN and AlGaN epitaxial layers. In addition, we investigate the influence of dislocations by a simple approach for bond and diffusion energies.