High quality GaN films on miscut (1 1 1) diamond substrates through non-c orientation suppression

Abstract

The GaN films are grown on 4° miscut to (110) and (100) orientation (111) diamond substrates by metal organic chemical vapor deposition respectively. The ordinary (111) diamond substrate is used as reference. The morphology and crystal quality of the three GaN films are characterized by atomic force microscope, scanning electron microscope, Raman spectra, photoluminescence, and X-ray diffraction (XRD). The GaN epilayer on miscut to (110) orientation (111) diamond presents a superior quality with smooth surface, clear A1(LO) peak of Raman shift and XRD rocking curve with full width half maximum of 1357 arcsec, which is a remarkable result reported. Through the analysis, we found that when GaN grows on miscut to (110) orientation (111) diamond substrates, non-c orientation grain would be greatly suppressed so that c orientation buffers easier to grow laterally and merge into thin films. The non-c orientation suppression process greatly improves the quality of GaN film on (111) diamond.