Impact of 3D growth and SiNx interlayer on the quality of (11–22) semi-polar GaN grown on m-plane sapphire

Abstract

We report the growth of semi-polar (11−22) GaN films with low defect densities on m-plane sapphire substrates by incorporating a porous SiNx interlayer in a three-stage growth process. The linewidth of X-ray diffraction rocking curves for our semi-polar GaN films decrease with increasing SiNx deposition time. Cross-sectional transmission electron microscopy analyzes confirm that the proposed three-stage growth process greatly reduces the semi-polar GaN threading dislocation densities down to 7 × 108 cm−2. Photoluminescence measurements demonstrate that InGaN/GaN quantum wells grown on our semi-polar GaN films provide peak intensities that are 26-fold greater than those grown on semi-polar GaN by a standard method.