Deposition of silicon carbon nitride thin films by microwave ECR plasma enhanced unbalance magnetron sputtering

Silicon carbon nitride thin films were prepared by microwave ECR plasma enhanced unbalanced magnetron sputtering. Chemical structure, mechanical and optical properties of the films as a function of graphite target voltage has been studied. The chemical structure in the deposited film is investigated with Fourier transform infrared spectroscopy (FTIR). The Si–C–N bonds increased from 17.14% to 23.56% while the graphite target voltage changed from 450 V to 650 V. The composition of SiCN thin films was analyzed by X-ray photoemission spectroscopy (XPS). The optical property was measured with UV–visible spectrophotometer. It was found that the transmittance of SiCN thin films decreases with the increasing carbon content; the optical gap value progressively decreases from 2.65 to 1.95 eV as the carbon content changes from 19.7% to 26.4%. The hardness of the thin films has been studied by nano-indentation, it increased with the graphite target voltage. The maximum hardness of the thin films reaches 25 GPa.