Aluminum gallium nitride grown by halide vapor phase epitaxy: growth on misoriented gallium nitride substrates

The focus of this study was to investigate the influence of substrate misorientation on the growth of aluminum–gallium nitride layers crystallized by Halide Vapor Phase Epitaxy on misoriented ammonothermal GaN seeds. Substrate misorientation was found to have a significant impact on both the morphology and aluminum incorporation in the resulting layers. It was observed that increasing the misorientation angle toward the m-plane (1 –1 0 0), relative to the c-plane (0 0 0 1), led to improved morphology and compositional uniformity. A layer with an average aluminum content of 8.8 at.% and exhibiting step-flow morphology was obtained. Based on the observation of the Borrmann effect in transmission X-ray topography, the layer can be classified as having good structural quality.