Elemental composition of reactively sputtered indium nitride thin films

Indium nitride (InN) thin films have been grown on a variety of substrates using low-temperature radio frequency reactive sputtering of indium metal in pure nitrogen plasma. Quantitative compositional analyses of the films, carried out using X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectrometry (RBS), suggest that large amounts of oxygen are present in them. The high concentration of oxygen in our films is attributed to the voided microstructure as revealed by cross-sectional scanning electron microscopy. The XPS studies also suggest that the oxygen incorporated into the films is bonded to nitrogen.