Growth and Separation of High Quality GaN Epilayer from Sapphire Substrate by Lateral Epitaxial Overgrowth and Wet Chemical Etching

Abstract

We report the growth and separation of a high quality GaN epilayer from a sapphire substrate using lateral epitaxial overgrowth (LEO) and a wet chemical etching process. A high quality GaN epilayer was grown by the LEO method using a SiO2-coated tungsten (W) mask. The LEO GaN epilayer was separated from the sapphire substrate by an etching solution injected through the voids formed by the chemical reaction of GaN with hydrogen gas under the W mask. The crystalline quality and optical properties of the separated GaN epilayer were improved by the reduction in threading dislocation and the release of stress in GaN.