Growth and Characterization of High Quality Continuous GaN Films on Si-Doped Cracked GaN Templates

It was found that continuous GaN films could be grown on cracked Si-doped GaN templates. Plan-view and cross section micrographs showed that no cracks occurred in the top GaN layer although it was grown on a cracked Si-doped GaN layer. The continuous GaN films on the cracked Si-doped GaN have been characterized by X-ray diffraction and Raman spectroscopy. It was shown that the top GaN film is of high crystal quality. A good surface morphology has been proven by scanning electron microscopy observations. Transmission electron microscopy analysis showed that the screw and/or mixed dislocation density in the top GaN film has been greatly reduced. However, pure edge dislocation density in the film remains unchanged.