Growth parameter dependence of HVPE GaN and polarity and crystal quality of the grown layers

Halide vapor phase epitaxy is a promising growth method for obtaining a free standing GaN substrate, especially when it is grown on a GaAs (111) substrate, but it depends on the growth parameters and conditions in a very complicated way. In this work, dependence of the growth rate and surface morphology on the deposition position, and polarity of the grown layer were investigated. It was found that the growth rate greatly depended on the position when the high-temperature growth was performed continuously to the buffer layer growth. It was demonstrated that GaN could be grown on GaAs (111) substrate at 1000degreesC without deterioration of 1 cm(2) GaAs substrate by optimizing the growth conditions. GaN grown at high temperatures had always Ga polarity, independent of the polarity of GaAs substrate and/or the GaN buffer layer. (C) 2002 Elsevier Science B.V. All rights reserved.