Effects of residual stress on the mechanical and structural properties of TiC thin films grown by RF sputtering

Titanium carbide thin films show attractive mechanical properties for engineering applications. Thin films of TiC were deposited on a 〈100〉 silicon substrate by RF sputtering from a TiC target. Various sputtering pressures were carried out in order to observe the influence of this parameter on structural and mechanical properties. The sputtering pressure was varied from 0.35 to 1 Pa at a sputtering power of 300 W. Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to characterize TiC thin films. Hardness was obtained by nanoindentation. Residual stress was determined by radius of curvature measurements. Lower pressures induce the formation of a distorted titanium carbide and a dense structure. In correlation to the lower pressure, large residual stress was measured and changed the TiC texture in XRD results. Both the compressive stress and the hardness exhibited a maximum value at a process pressure using pure argon at 0.35 Pa with a pressure of 1 Pa necessary to obtain TiC films with 〈111〉 texture.