Effect of growth temperature of AlN interlayers on the properties of GaN epilayers grown on c‐plane sapphire by metal organic chemical vapor deposition

Abstract

AbstractThe effect of growth temperature of AlN interlayers on the properties of GaN epilayers grown on c‐plane sapphire by metal organic chemical vapor deposition has been investigated by high resolution X‐ray diffraction (HRXRD) and Raman spectroscopy. It is concluded that the crystalline quality of GaN epilayers is improved significantly by using the high temperature AlN (HT‐AlN) interlayer in GaN buffers. The density of threading dislocation is reduced especially for edge type dislocations. Higher compressive stress exists in GaN epilayers with HT‐AlN interlayer than with low temperature AlN (LT‐AlN) interlayer, which is related to the reduction of strain relaxation caused by the formation of misfit dislocation. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)