Photoreflectance study of AIN thin films grown by reactive gas-timing rf magnetron sputtering

Band-gap energy of AIN thin films was investigated by room-temperature photoreflectance (PR) spectroscopy. Using rf magnetron sputtering, the reactive gas-timing technique was successfully applied to grow cubic-AIN thin films. The define XRD patterns of all deposited films show orientation of cubic structure in (111) and (200) planes. The PR spectra clearly exhibit a band-gap energy of cubic-AIN depending on the flow rate of N-2 gas. The band-gap transition energies were determined by fitting the PR spectra to theoretical line-shape expression. The band-gap transition energies decreased with increasing flow rate of N-2.