The Effect of RF Magnetron Sputtered AlN Buffer in GaN Epitaxy by MOVPE on the m-plane Sapphire

The GaN films deposited by metal organic vapor phase epitaxy (MOVPE) on m-plane sapphire using sputtered AlN as buffer with different oxygen and nitridation deposition conditions were studied. We find the suitable PVD condition that can be used for semi-polar GaN epitaxy. Only using nitridation for preparation and non-oxygen gas during deposition can result in a single crystal structure of semi-polar GaN. Further researches on the nitridation durations and film thicknesses have been discussed as well. By adjusting the nitridation and deposition durations appropriately, the photoluminescence (PL) intensities of GaN increased by 200% indicating the improvements of crystal qualities. The PVD AlN can replace the GaN buffer which may substantially reduce the epitaxy time and improve the crystalline quality of epi-layers.