GaN films deposited by middle-frequency magnetron sputtering

GaN films were deposited on Si (111) substrates by middle-frequency magnetron sputtering. X-ray diffraction revealed preferential GaN (0 0 0 2) orientation normal to the substrate surface for all the films deposited. The diffraction intensity and N contents were found to depend strongly on the total gas pressure. Good quality films were only obtained at pressures in the range of 0.4-1.0 Pa. Little diffraction of GaN (0 0 0 2) could be observed either at total pressures below 0.4 Pa or above 1.0 Pa. The GaN films produced under the optimized conditions have an N:Ga ratio of 1:1 as determined by energy-dispersive X-ray spectroscopy.