Epitaxial ScN(001) Grown and Analyzed In situ by XPS and UPS. I. Analysis of As-deposited Layers

X-ray and ultraviolet photoelectron spectroscopies (XPS and UPS) were used to characterize as-deposited ScN(001) layers grown in situ. The films were deposited by ultrahigh vacuum reactive magnetron sputtering on MgO(001) at 800 °C in pure N2 discharges maintained at a pressure of 5 mTorr (0.67 Pa). Mg Kα and monochromatic Al Kα x-ray sources were used to obtain the XPS spectra, while the UPS data were generated by He I and He II UV radiation. The spectra show that the ScN(001) surfaces are free of O and C. The films were found to have a slight excess of nitrogen, in agreement with Rutherford backscattering spectroscopy (RBS) results, yielding a N/Sc ratio of 1.11 ± 0.03.