Synthesis of carbon nitride thin films by vacuum arcs

Carbon nitride (CN) thin films were synthesized by combining vacuum arcs and plasma ion implantation techniques. Three methods were investigated: plasma ion implantation into carbon films deposited by anodic vacuum arcs (AAPII), continuous cathodic vacuum arc with plasma ion implantation (CAPII) and pulsed cathodic vacuum arc (PCA). The films were found to be amorphous by X-ray diffraction (XRD). X-Ray photoelectron spectroscopy (XPS) and Raman spectroscopy analysis indicated the formation of CN, CN and C≡N bonds. Calculations of the surface tension components (dispersion and polar) of the films using the contact angle measurement technique suggested the formation of covalent carbon-nitrogen bonds. The CN films exhibited improved adhesion relative to the pure carbon films as indicated by adhesion calculations and the reduction in interfacial tension between the films and the substrate. A hardness of 18.9 GPa was obtained by nanoindentation measurements for CN films with an N/C ratio of 0.135.