Residual Stress Evolution by the ex-situ Annealing of TiN Thin Films Deposited on Steel Substrates

TiN thin films were deposited on high speed steel substrates by a PVD method at substrate temperatures of 450 °C (film A) and 200 °C (film B). Structural properties of the films were studied by X-Ray diffraction and atomic force microscopy. Residual stresses in the films are determined by a X-Ray diffraction method. It is found that film A has an average residual stress of about 8 GPa and a rougher surface. Film B has a smoother surface and a larger residual stress (12 GPa). By annealing at a temperature of 450 °C for four hours, the residual stress in film B is reduced to the same level as that in film A. The mechanisms which affect the residual stress of TiN films will be discussed.