The effect of N2 partial pressure on the properties of Nb–Si–N films by RF reactive magnetron sputtering

Nb–Si–N films were sputtered by RF reactive magnetron sputtering with various N2 partial pressure in argon and nitrogen gas mixture. The characterizers of Nb–Si–N films were performed with energy dispersive spectroscopy, four-point probe method, X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscope, and transmission electron microscope, respectively. The results reveal that the Nb/Si ratio of Nb–Si–N films decreases as N2 partial pressure increases. The microstructure of Nb–Si–N films is of a nano-composite that consists of amorphous SiNx phase and nano-sized NbN crystallites embedding in amorphous SiNx matrix. When sputtered with high N2 partial pressure there is more amorphous SiNx phase in Nb–Si–N films and the grain size of NbN decreases. High N2 partial pressure is in favor of the growth of hcp ε-NbN phase in the Nb–Si–N films. The value of surface roughness of Nb–Si–N films decreases as N2 partial pressure increases.