The morphology on the surface of the GaN homo-epitaxial film grown by HVPE

Bulk GaN materials were grown by hydride vapor phase epitaxy in order to produce a GaN freestanding substrate. The defects, such as pits, pyramids and leaf-like pattern of Ga droplets were found in the GaN film with a scanning electronic microscope and an atom force microscope. The crack existed in the interface between the epitaxial layer and substrate or on the surface of the GaN film. The morphology characters and the effects on the quality of the GaN epilayer were studied.