Influence of Ammonia Flow on Microstructural Properties of Polar GaN Layers Grown by HTVPE on Sapphire Substrates

Abstract

AbstractIn this contribution, the correlation between the microstructure of thin gallium nitride films and the ammonia flow applied during their growth by high‐temperature vapor phase epitaxy is described. The films were grown directly on (001)‐oriented sapphire substrates. Their microstructure was investigated using high‐resolution X‐ray diffraction, electron microscopy and micro‐Raman spectroscopy. The ammonia flow was found to affect the residual stress, the density of threading dislocations, the density of basal‐plane stacking faults and the density of inversion domain boundaries. It is shown that the ammonia flow is an important parameter of the deposition process that can be used to reduce concurrently the residual stress and the density of microstructure defects.