The influence of Ti doping on the mechanical properties of TaN film

Titanium and tantalum nitride films (TixTa1 − xN) with different Ti concentrations (0.15 < x < 0.51) were synthesized on bearing steels by ECR-microwave plasma source enhanced DC magnetron sputtering, and the influences of Ti contents on the structures and mechanical properties of TixTa1 − xN films were investigated. The thickness and morphology of films were observed by scanning electronic microscope (SEM). Composition analysis of the films was carried out by energy dispersive spectroscopy (EDS) in SEM. Structure was investigated by X-ray diffraction (XRD). Mechanical properties were evaluated using nano-indentation and scratch tester. The results showed that the orientations of (111) and (002) presented in TixTa1 − xN films with different atomic concentrations of titanium. The minimal grain size of TaN film was lower than 14 nm grown with Ti contents around 22%, and varied strongly with the dopant and doping level. Similarities were in changes of the mechanical properties, the mechanical properties including hardness, modulus, plasticity and adhesion were also sensitive to the Ti concentrations, and were obviously improved with Ti contents around 22%, indicating a strong correlation between these properties. All of the performances indicated that appropriate addition of Ti into TixTa1 − xN films results in the improvement of mechanical properties.