Advanced HEMT characteristics of epitaxial quality-improved GaN by using patterned sapphire

An efficient method to modify the defect density of a gallium nitride (GaN) epi-wafer is proposed in this study. A patterned sapphire substrate (PSS) was used here acting as the medium for defect adjustment. The characteristics of yielded samples were analyzed by Raman scattering and etching pitch density (EPD) methods, which did show the improved crystal quality of GaN. Following high electron mobility transistor (HEMT) application based on the yield sample was executed, and the performances of the devices did improve as well.