Structures and mechanical properties of TiN/SiNx multilayer films deposited by magnetron sputtering at different N2/Ar gas flow ratios

Polycrystalline TiN/SiNx multilayer films are deposited using reactive magnetron sputtering Ti and Si, respectively, discharging a mixture of N2 and Ar gas with different N2/Ar gas flow ratios, and their structures and mechanical properties are characterized by X-ray reflectivity (XRR), X-ray diffraction (XRD) and nanoindentation. It is found that when the N2/Ar gas flow ratio is low, the interface between TiN and SiNx layer for the obtained TiN/SiNx film is sharp and the preferred orientation for TiN layer is TiN (200). In contrast, when the N2/Ar gas flow ratio is high, the interface becomes rough and the preferred orientation for TiN layer changes to TiN (111). Nanoindentation experiments exhibit that the TiN/SiNx film with a TiN (111) preferred orientation is harder than that with a TiN (200) preferred orientation, and all films have nano-scale fracture characteristics.