Epitaxial growth of a self-separated GaN crystal by using a novel high temperature annealing porous template

Abstract

In this paper, a MOCVD-GaN/Al₂O₃ (MGA) template was annealed under appropriate annealing conditions and N₂ flow to form a porous template. The porous template was used for growing GaN by HVPE. The GaN crystal was easily separated from the porous template with the assistance of the microporous structure. The self-separated GaN crystal grown on the porous template showed a smaller full width at half maximum (FWHM) for (002) and (102) reflections in the HRXRD measurement than that grown on the MGA template. The PL results indicate that the optical quality of the GaN crystal on the porous template was improved and the dislocation density decreased. The Raman results showed that the stress in the GaN crystal grown on the porous template is much smaller than that on the MGA template. These results show that the crystalline quality of GaN crystals was improved by using the porous template.