Heteroepitaxial Lateral Overgrowth of GaN on Periodically Grooved Substrates: A New Approach for Growing Low-Dislocation-Density GaN Single Crystals

Abstract

Using periodically grooved substrates, we propose a new approach to the growth of low-dislocation-density GaN single crystal. Three different substrates of basal-plane sapphire, 6H-SiC(0001)_Si and Si(111) were used. Each substrate's surface geometry was formed as periodical straight trenches oriented in either the _GaN or _GaN direction. No selective-growth mask of dielectric or metallic materials was deposited on any part of the substrates during the growth. The laterally grown area had etch pit densities of 4×10⁶ cm^-2 or less.