Low-temperature growth of InxGa1−xN films by radio-frequency magnetron sputtering

The low-temperature growth of InxGa1−xN films on quartz glass substrates utilizing radio-frequency magnetron sputtering is investigated. In the InxGa1−xN films prepared using an In–Ga alloy target, grazing incidence X-ray diffraction (GIXRD) peaks corresponding to wurtzite structure were observed. X-ray photoelectron spectroscopy (XPS) was applied to study the extent of oxygen contamination and chemical states, and secondary ion mass spectrometry (SIMS) was used to evaluate the distribution profiles of oxygen impurity in the as-grown InxGa1−xN thin films. XPS and SIMS analysis indicate that the entire thin films have oxide phases. However, no evidence of In2O3, Ga2O3, or indium oxynitride phases was shown in XRD studies. It may be predicted that the oxygen impurities formed amorphous oxide phases embedded in InxGa1−xN matrix. According to our findings, indium is a major phase in the InxGa1−xN thin films which suggests that a significant amount of indium remains un-reacted with N2. The optical transmittance spectra of the as-grown films show interference fringe patterns. The indium fraction x of the as-deposited InxGa1−xN thin films can be calculated out by the transmittance data.