Surface morphology study of basic ammonothermal GaN grown on non-polar GaN seed crystals of varying surface orientations from m-plane to a-plane

摘要

GaN crystals were grown on hydride vapor phase epitaxy (HVPE) GaN seed crystals with non-polar surface orientations varying between on-axis m-plane and a-plane using the basic ammonothermal method. Three different surface morphology regimes were observed with the surface features including mounds, slate-like morphologies, and pyramidal 'spikes' composed of (0001) and non-polar micro-facets. A macroscopic off-orientation of the non-steady-state surface and newly appearing steady-state growth surfaces towards [0001] by approximately 1° was observed with geometric constraints suggesting an off-orientation of the observed {10-10} microfacets towards [000T] by approximately 1° or greater.