Study of AlN based materials grown on nano-patterned sapphire substrates for deep ultraviolet LED applications

Abstract

High quality and crack-free AlN films were obtained by using nano-patterned sapphire substrates (NPSS) grown at AMEC Prismo HiT3TM MOCVD platform. It is believed that the introduced epitaxial lateral overgrowth can annihilate most of dislocations and the grain boundary induced tensile stress can be significantly suppressed by NPSS. For a 5 μm thick AlN film, FWHMs of 173 arcsec and 335 arcsec were observed from AlN (002) and (102) X-ray rocking curves, respectively, indicating the high crystalline quality. The surface of AlN films grown on NPSS shows a typical step-bunching morphology with atomic steps on the bunched terrace. In addition, we also obtained excellent thickness uniformity for AlN films grown on NPSS with within-wafer and wafer-to-wafer thickness uniformity of 0.69% and 0.92%, respectively.