Evolutionary growth strategy of GaN on (1 1 1) diamond modulated by nano-patterned buffer engineering

GaN-on-diamond wafers are investigated to overcome the heat accumulation issues in GaN-based electronic devices. Until now, growing the high-quality GaN film on the diamond for device manufacture is still a great challenge. In this study, a new strategy of high-quality GaN on (111) diamond was proposed for the realization of high-performance GaN-on-diamond devices. The nano-patterned buffer engineering was utilized to greatly improved the GaN film on (111) diamond. The Al0.78Ga0.22N nano-patterned buffer reformed the morphology, ensuring that c orientation is the primary growth direction. The subsequent overgrowth of Al0.47Ga0.53N broadened the nano pillars and introduced stacking faults, improving the coalescence process and dislocations blockage. In addition, the coalescence process of the Al0.26Ga0.74N layer bent the treading dislocations, inducing the dislocations to annihilate. As a result, we could obtain remarkably high-quality GaN films on (111) diamond. The high-resolution X-ray diffraction rocking curve showed a full width at half maximum (FWHM) value of 770/986 arcsec at (002)/(102), which is the narrowest result reported. To the best of our knowledge, the RC FWHM at (102) of epitaxial GaN on diamond is reported firstly. Overall, this study provided a new strategy for obtaining high-quality GaN films on (111) diamonds for high-performance GaN-on-diamond devices.