MAGNETRON-SPUTTERED CARBON NITRIDE FILMS

Carbon nitride (CNx) thin film deposition was undertaken in a closed-f ield, unbalanced magnetron system. Reactive deposition utilised a grap hite target in an argon/nitrogen plasma. The main deposition parameter s investigated were magnetron current, total gas pressure and nitrogen gas partial pressure. The films deposited were examined using IR spec troscopy, ellipsometry, and X-ray diffraction (XRD). Analysis of the r esults yielded the following characteristics: refractive index of nitr ogen-containing films was reduced below that for pure carbon films but had little dependence on substrate bias and total gas pressure. It wa s, however, strongly dependent on the magnetron current at which the f ilm was deposited. IR spectroscopy showed the transmittance of the fil ms for given deposition conditions to be a monotonic function of nitro gen content. The deposition conditions themselves also had a significa nt effect, in particular the magnetron current. In addition, C=N bondi ng was evident from the absorption bands observed. Structural analysis by means of XRD showed that the amorphous nature of the films with so me degree of graphitic content depended more on the deposition paramet ers than on the nitrogen concentration. Increased graphitic-type struc ture was observed at low magnetron currents, high system pressure and large (negative) substrate bias.