The universality classes in growth of iron nitride thin films deposited by magnetron sputtering

Fe-N thin films were deposited on glass substrates by DC magnetron sputtering at different Ar/N2 discharges (N2 fraction of 30, 10, and 5%, respectively). The composition of the films was analyzed by using X-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD), grazing incidence X-ray scattering (GIXS), and atomic force microscopy (AFM) were used for analyzing the structure and the universality classes. Films deposited at different nitrogen pressures exhibited different structures with different nitrogen contents. The FeN, ε-Fe3N, FeN0.056 were detected in iron nitride films which deposited at N2 fractions of 30, 10, and 5%, respectively. The exponents for all of them are in agreement with KPZ universality classes