Influence of nitrogen partial pressure on the microstructure and morphological properties of sputtered RuN coatings

In this work, the production of RuN thin films using the reactive direct current magnetron sputtering technique is presented. Samples were grown with varying Ar/N2 ratio with values of 60/40, 80/20, 85/15, 90/10, 95/5, and 100/0. X-ray photoelectron spectroscopy was employed to determine the presence of RuN before and after a sputtering etching process. According to the high-resolution of N1s spectra, 3 peaks were identified at 397.4 ± 0.3 eV, 398.3 ± 0.3 eV, and 398.8 ± 0.3 eV binding energies, corresponding to hybridizations of nitrogen with transition metals, oxynitrides, and oxycarbides. X-ray diffraction analyses were performed, showing the coexistence of the RuN face-centered cubic and Ru hexagonal compact packed phases. After the etching process, the samples grown at nitrogen flow rates greater than 15% continued to show the RuN face-centered cubic phase. Atomic force microscope analyses showed that as the nitrogen concentration increased, the grain size and roughness also tended to increase.