Effect of nitrogen content on nanostructure and mechanical properties of TiC x N y thin films

Abstract

A series of TiC_xN_y thin films were deposited at 500°C on Si (100) substrates by way of incorporation of different amounts of nitrogen into TiC_0·45 using reactive unbalanced dc magnetron sputtering method. Their phase configurations, microstructures and mechanical behaviours were subsequently investigated by X-ray diffraction, X-ray photoelectron spectroscopy and microindentation methods. The result indicated that TiC_0·45 showed a fcc-like B-NaCl polycrystallite, and a solid solution nanocrystalline (nc-) TiC_xN_y with the same structure was formed by way of dissolution of nitrogen into TiC_0·45 lattice when the atomic ratio of (C+N)/Ti was less than one unit. Both hardness and residual compressive stress values were increased with increasing N content. Their maximums were believed to be obtained at nc-Ti(C,N) solid solution with an atomic ratio of one unit. Enhancement of both of them was attributed to solid solution.