Microstructural and mechanical properties of sputter deposited TiN/SiNx multilayer thin films

TiN/SiNx multilayer films were deposited on Si (1 0 0) substrate by DC/RF magnetron sputtering. The effect of varying deposition parameters on the structural and mechanical properties of TiN/SiNx multilayer films was investigated by several characterization techniques such as XRD, FE-SEM, AFM, TEM and nanoindentation technique. XRD analysis of the films, with varying SiNx layer thickness, revealed the (1 1 1), (2 0 0) and (2 2 0) orientation and with variation of TiN layer thickness, same orientations were observed initially but (2 0 0) orientation has increased with increase of TiN layer thickness. The grain size of the multilayers calculated by TEM was found to be 13.0–15.0 nm with varying SiNx layer thickness but it varied from 3.8 to 29.7 nm with increasing TiN layer thickness. The surface roughness of the TiN/SiNx multilayer was calculated from its AFM images and it remains constant with varying SiNx layer thickness but increases in the other cases, with varying TiN layer thickness. The hardness and Young's modulus values of TiN/SiNx multilayer films have increased up to 31.4 and 365.8 GPa, respectively, with varying SiNx layer thickness (1.2 nm) but it decreased beyond the SiNx layer thickness of 1.2 nm. In the other case, the hardness and Young's modulus values of TiN/SiNx multilayer films have increased initially, with increase in thickness for TiN layer, followed by uniform decrease and then finally it has increased sharply up to 33.4 and 370.5 GPa, respectively.