Hard carbon nanocomposite films with low stress

Ti- and Al-containing carbon nanocomposite films were deposited by the filtered cathode vacuum arc technique. The influence of Ti and Al content in the target on the surface morphology, structure, internal stress, hardness and Young's modulus of the deposited films were studied. The surface of all carbon nanocomposite films was atomically smooth. The incorporation of metal atoms in the films led to an increase in surface roughness and I_D/I_G ratio. The RMS and I_D/I_G ratio of ta-C:Al films was higher than that of ta-C:Ti films deposited from a target with the same metal content. The incorporation of both Ti and Al atoms in ta-C films resulted in a decrease in internal stress, hardness and Young's modulus. The effect of Al on the internal stress, hardness and Young's modulus of carbon nanocomposite films was more pronounced than that of Ti. For ta-C:Ti and ta-C:Al films deposited from a target with a metal content of 10 at.%, the internal stress was reduced to 4.29 and 1.94 GPa, respectively, whereas the hardness remained at a high level (24 and 18 GPa, respectively). Raman spectra clearly indicate that the Ti atoms in ta-C:Ti films exist as a TiC phase, which contributes to the higher internal stress, hardness, and Young's modulus of ta-C:Ti films.