PREPARATION OF GAN FILM OF LOW CARRIER DENSITY BY THE HWE SYSTEM WITHGA AND TMG SOURCES

GaN films with low carrier density of the order of 10(16) cm(-3), smoo th and mirror like surface morphology, and good crystalline quality we re prepared on a (0 0 0 1)sapphire substrate by the hot wall epitaxy s ystem using Ga metal and TMG gas source, respectively. To investigate the dependence of the quality on the thickness of the GaN buffer layer , several ramping rates were performed between the growth of, the buff er and the epi-layer. A simple model is proposed to explain the result s. (C) 1998 Published by Elsevier Science B.V. All rights reserved.