Threading dislocation reduction in a GaN film with a buffer layer grown at an intermediate temperature

Abstract

Remarkable reduction of the threading dislocation (TD) density has been achieved by inserting a GaN layer grown at an intermediate temperature (900 • C) (IT-GaN layer), just prior to the growth of GaN at 1040 • C by using a hydride vapor phase epitaxy. The variation in the dislocation density variation along the growth direction was observed by using cathodoluminescence (CL) and transmission electron microscopy (TEM). A cross-sectional CL image revealed that the reduction of the TD density happened during the growth of IT-GaN layer. The TEM measurement provided the proof that the TD reduction could be ascribed to the masking of the TD by stacking faults in the IT-GaN layer.