Influence of Si content on the microstructure and mechanical properties of VSiN films deposited by reactive magnetron sputtering

•By using XRD, HRTEM and XPS, the microstructure of the VSiN films was studied in details.•The microhardness and stress of VSiN films were investigated in details.•A new simple four-stage model was proposed.

A series of VSiN composite films with different Si content were deposited at room temperature by reactive magnetron sputtering. XPS, XRD, SEM, SAED, HRTEM, 3D Profilometer and Nano-indentation were employed to characterize the composition, microstructure, cross-sectional morphology and mechanical properties of the films. The results reveal that the c-VN phase and t-V5N phase coexist in films with different Si content and the c-VN is the major phase. The substitutional solid solution of (V,Si)N is formed when the Si content is less than 1.3 at.%. With a further increase of Si content, excess Si are aggregated in the grain boundary and amorphous Si3N4 is formed. It was found that minute traces of Si atoms can promote the growth of grain. A two-dimensional model was built in this study to reveal the existing forms of Si element and its influence on the microstructure and mechanical properties of VSiN films at different stages of the modelling process.