Epitaxial ScN(001) Grown and Analyzed In situ by XPS and UPS. II. Analysis of Ar+ Sputter Etched Layers

X-ray and ultraviolet photoelectron spectroscopies (XPS and UPS) were used to characterize as-deposited epitaxial ScN(001) layers grown in situ which were Ar+ sputter etched. The films were deposited by ultrahigh vacuum reactive magnetron sputter deposition on MgO(001) at 800 °C in pure N2 discharges maintained at a pressure of 5 mTorr (0.67 Pa) and shown to have a N/Sc ratio of 1.11 ± 0.03 by Rutherford backscattering spectroscopy (RBS). The films were sputter etched with 3 keV Ar+ at an angle of 40° until a constant nitrogen-to-scandium ratio was established. A Mg Kα x-ray source was used to obtain the XPS data, while the UPS data was generated by He I and He II UV radiation. The sputter etched films have a N/Sc ratio of 0.99 indicating a preferential removal of nitrogen.