Improvement of crystal quality HVPE grown GaN on an H3PO4 etched template

Abstract

In this paper, GaN films were grown on an H₃PO₄ etched MOCVD-GaN/Al₂O₃ template (EMGA) by hydride vapor phase epitaxy (HVPE). The GaN film grown on the EMAG template showed a smaller full width at half maximum (FWHM) of the (002) and (102) reflections in the XRD measurement than that grown on the MOCVD-GaN/Al₂O₃ (MGA) template. A stronger PL band edge emission was observed for the GaN grown on the EMGA template compared to the MGA template. Defect related yellow luminescence was observed for GaN grown on the MGA template, which did not appear for the EMGA template. The Raman results showed that the stress of the GaN grown on the EMGA is much smaller than that on the MGA template. The penetrated etch pits played an important role in the reduction of threading dislocations. These results indicate that the quality of the GaN films is improved by using an EMGA template.