Characterization of high-quality relaxed flat InGaN template fabricated by combination of epitaxial lateral overgrowth and chemical mechanical polishing

Abstract

We report the characterization of thick completely relaxed InGaN layers grown using epitaxial lateral overgrowth (ELO) with a facet structure. ELO-InGaN layers were successfully grown on a stripe-patterned GaN template. The full width at half maximum of the X-ray rocking curve of ELO-InGaN on the InGaN templates was smaller than that of non-ELO InGaN. Because of the difficulty in improving the morphology of ELO-InGaN layers grown on patterned GaN templates, chemical and mechanical polishing (CMP) was performed to obtain a flat c-plane surface. The photoluminescence intensity of InGaN/GaN multiple quantum wells (MQWs) on the CMP-ELO-InGaN template was approximately two times stronger than that of MQWs on the GaN template. Furthermore, the peak wavelength of the MQWs on the CMP-ELO-InGaN template was longer than that on the GaN template because of the high In pulling effect.