A study was made of the possibility of surface-treating sapphire, using reactive ion beam pre-treatment, as an alternative process for GaN growth via metalorganic chemical vapour deposition. As a result of the reactive ion beam treatment, etching of the sapphire surface and the formation of a very thin disordered AlON layer, occurred. The latter partially crystallized during the growth of GaN. A reduction in the dislocation density and in the lattice strain of GaN on treated sapphire was obtained. Partial crystallization in the reactive ion beam-treated layer promoted 2-dimensional growth on the crystallized regions, and relieved misfit strain via relaxation of the disordered reactive ion beam-treated layer.

Effects of Reactive Ion Beam Treatment of a Sapphire Surface to Optimise the Deposition of GaN Films H.J.Kim, D.Byun, G.Kim, D.W.Kum: Journal of Applied Physics, 2000, 87[11], 7940-5