Properties of carbon nitride films with composition ratio C/N=0.5–3.0 prepared by the ion and vapor deposition method

Carbon nitride films with the composition ratio CR(C/N)=0.5–3.0 were prepared by the ion and vapor deposition method, where carbon was evaporated on various substrates while being simultaneously bombarded with 0.5–10.0 keV nitrogen ions. The properties of the films were studied by x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometry (FT-IR), ultraviolet transmission spectroscopy, x-ray diffraction, and hardness measurements. The films formed at energies lower than 0.8 keV and CR(C/N)=0.6–0.7 on tungsten carbide showed the highest Knoop harness of 6400 kgf/mm2 on films with 1 μm thickness and a maximum optical band gap of 2.7 eV. X-ray diffraction measurements demonstrated that all films have an amorphous structure. The XPS and FT-IR studies indicated that the peak newly observed at 286.3 eV in the C-1s1/2 XPS spectra arises from triple bonding C≡N.