GAN GROWTH USING GAN BUFFER LAYER

High-quality gallium nitride (GaN) film was obtained for the first time using a GaN buffer layer on a sapphire substrate. An optically flat and smooth surface was obtained over a two-inch sapphire substrate. Hall measurement was performed on GaN films grown with a GaN buffer layer as a function of the thickness of the GaN buffer layer. For the GaN film grown with a 200 angstrom-GaN buffer layer, the carrier concentration and Hall mobility were 4 x 10(16)/cm3 and 600 cm2/V.s, respectively, at room temperature. The values became 8 x 10(15)/cm3 and 1500 cm2/V.s at 77 K, respectively. These values of Hall mobility are the highest ever reported for GaN films. The Hall measurement shows that the optimum thickness of the GaN buffer layer is around 200 angstrom.