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

Abstract

TiN/SiN x 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/SiN x 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 SiN x 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 SiN x layer thickness but it varied from 3.8 to 29.7 nm with increasing TiN layer thickness. The surface roughness of the TiN/SiN x multilayer was calculated from its AFM images and it remains constant with varying SiN x layer thickness but increases in the other cases, with varying TiN layer thickness. The hardness and Young's modulus values of TiN/SiN x multilayer films have increased up to 31.4 and 365.8 GPa, respectively, with varying SiN x layer thickness (1.2 nm) but it decreased beyond the SiN x layer thickness of 1.2 nm. In the other case, the hardness and Young's modulus values of TiN/SiN x 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.