Low Defect density of GaN fabricated by compound pattern sapphire substrate

Using a patterned sapphire substrate (PSSs) in the epitaxial gallium nitride thin film can reduce the threading dislocation density and increase the crystal quality, and reduce the defect density (defect density). Commercial patterned sapphire substrate has single period microstructure; however , we have two different period microstructure on the sapphire substrate, but we found that with the change between the different microstructures of the top c-plane size and microstructure of different cycles difference, gallium nitride crystal growth will present two very different faces, and are subject to different stress, which can affect the efficiency of the use made of the subsequent electronic components. In the final stage, this paper will discuss the stress and defect density between compound patterned sapphire substrates and commercial patterned sapphire substrate (CPSSs). Compound patterned sapphire substrate suffered only about half the amount of stress with commercial patterned sapphire substrate. Using appropriate periodic microstructures, stress and defect density will decrease; thus improving efficiency of electronic devices which was grown on the gallium nitride thin film.