Dislocation defects in a GaN epilayer grown on a low-temperature GaN-rich GaNP (LT-GaNP) buffer on sapphire substrate by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) were investigated by means of transmission electron microscopy and atomic force microscopy. The GaNP-buffer-based high-temperature GaN (HT-GaN) layers had a dislocation density as low as 5 x 108/cm2, which could be compared to the best results for GaN epilayers grown on sapphire by atmospheric pressure MOCVD by using the conventional LT-GaN or -AlN buffer. The dislocation density reduction could be predominately attributed to an enhanced lateral overgrowth for the HT-GaN layer grown on a GaNP buffer, which was confirmed by the observation of a special morphology evolution beginning from the GaNP buffer.

Dislocation Reduction in GaN Epilayers Grown on a GaNP Buffer on Sapphire Substrate by Metalorganic Chemical Vapor Deposition. H.Li, M.Tsukihara, Y.Naoi, S.Sakai: Japanese Journal of Applied Physics - 2, 2002, 41[11B], L1332-5