Growth condition dependence of structure and surface morphology of GaN films on (111)GaAs substrates prepared by reactive sputtering

GaN films were grown on (111)GaAs substrates by radio frequency magnetron sputtering in an ambient of nitrogen using a pure gallium target. The effect of the growth condition including the substrate temperature and the sputtering pressure on the structural properties of GaN films was investigated in relation to the surface morphology. It was found that both the substrate temperature and the sputtering pressure strongly affect the surface morphology and crystalline quality. High-quality crystalline GaN film with smooth surface could be obtained at a substrate temperature of 700 deg. C with a sputtering pressure of 45 mTorr. Based on the experimental results, the growth mechanism for reactive sputtered GaN films was discussed