Optimizing rf Power for Preferential C≡N Bond Formation in a-CNx Thin Films Prepared by rf-PECVD Technique

Effects of rf power on the chemical bonding in carbon nitride films deposited using radio-frequency (rf) plasma enhanced chemical vapor deposition in pure methane and nitrogen gas mixtures were investigated. The rf power was varied from 60 to 100 W. The deposition rate of the films increased constantly with increasing rf power up to 80W, before saturating with further increase in rf power. Fourier transform infra-red spectroscopy (FTIR) studies showed a systematic change in the spectra and revealed three main peaks namely the G-peak, D-peak and C≡N triple bond. This work showed that rf power has significant effects on the chemical bonding of the a-CNx films and the optimum rf power for the high C≡N absorption intensity is 80 W.