Growth and properties of CNx films prepared by reactive DC magnetron sputtering

Carbon nitride (CNx) films have been deposited by reactive sputtering of a graphite target with nitrogen and/or argon eases. A modified cylindrical DC magnetron was used as a sputter deposition source and the processing plasma was monitored by means of both a Langmuir probe and optical emission spectroscopy (OES). The nitrogen to carbon ratio (N/C ratio) evaluated by X-ray photoelectron spectroscopy (XPS) ranged from 0 to 0.5. Strong correlation between N/C ratio in the film and N-2(+)/N-2* emission intensity ratio was confirmed from the result of the OES study. An absorption band near 2200 cm(-1) in the Fourier transform infrared (FT-IR) spectra strongly indicated the existence of C=N covalent bonding. Transmission electron microscopy (TEM) bright-field imaging revealed that the prepared CNx film contained nanocrystallines buried in the amorphous background and the observed grain size was 10-60 nm range.