Semipolar (202¯1) GaN and InGaN quantum wells on sapphire substrates

Here, we demonstrate a process to produce planar semipolar (202¯1) GaN templates on sapphire substrates. We obtain (202¯1) oriented GaN by inclined c-plane sidewall growth from etched sapphire, resulting in single crystal material with on-axis x-ray diffraction linewidth below 200 arc sec. The surface, composed of (101¯1) and (101¯0) facets, is planarized by the chemical-mechanical polishing of full 2 in. wafers, with a final surface root mean square roughness of