EBSD crystallographic orientation research on strain distribution in hydride vapor phase epitaxy GaN grown on patterned substrate

Abstract

A GaN crystal was grown by hydride vapor phase epitaxy (HVPE) on a substrate with patterned SiO₂ masks. The growth mode of HVPE-GaN was analysed, and the crystallographic orientation relationship between GaN and the sapphire substrate was identified by electron backscatter diffraction (EBSD) Kikuchi diffraction patterns and pole figures. The lattice mismatch was calculated from the crystallographic orientation relationship of the heteroepitaxial structure and the lattice parameters. EBSD mapping was employed to investigate the disorientation distribution of GaN along the [001] direction. The GaN strain in the heteroepitaxial structure was identified from the crystallographic orientation information. Raman spectrum results demonstrated that the residual stress in GaN was beneficially reduced in this growth mode.