Comparison of GaN Buffer Layers Grown on GaAs (111)A and (111)B Surfaces

摘要

Comparison of low-temperature (LT-) GaN buffer layers grown on GaAs {111} surfaces has been performed. LT-GaN buffer layers of 0-160nm thickness were grown simultaneously both on GaAs (111)A and (111)B surfaces by metalorganic hydrogen chloride vapor phase epitaxy (MOHVPE) at 550°C. On GaAs (111)A surface, the LT-GaN buffer layers showed smooth surface and covered the GaAs homogeneously. On GaAs (111)B surface, however, the LT-GaN buffer layers showed rough surface with some pits, and surface roughness increased with increasing thickness of the LT-GaN buffer layer. Due to the poor morphology of the LT-GaN buffer layers on GaAs (111)B, the GaAs was eroded during subsequent heating up to 1000°C in NH_3 ambient, whereas no deterioration was observed on GaAs (111)A surfaces covered with the LT-GaN buffer layers.