Raman analysis of Si–C–N films grown by reactive magnetron sputtering

Silicon carbon nitride thin films have been deposited by reactive magnetron sputtering of silicon and graphite targets in mixed Ar/N2 atmosphere at substrate temperature of 300 °C. The substrate bias voltage varied from -50 up to +50 Vand the nitrogen flow rate varied from 0 to 20 sccm. The as-deposited films were analyzed by Raman spectroscopy (RS) and X-ray photoelectron spectroscopy (XPS). The Raman analyses show that the film without nitrogen incorporation has mixed sp2–sp3-hybridized carbon structures while those with nitrogen introduction give rise to nitrogen-bound sp1-, sp2- and sp3-coordinated carbon structures as well as Si–N phase. The change of the D band position (~1360 cm-1), FWHM and its relative intensity with respect to the G band (~1595 cm-1), ID/IG, seem to be correlated with the formation of these phases and therefore to the deposition conditions. XPS analyses not only confirm the bonding natures revealed by Raman spectroscopy, but also give quantitatively the relative importance of the phases. It was shown that the area ratio of the nitrogen-bound sp3- to sp2-coordinated carbon bonds is: 1.41:1.38:1.8:3.19 and that of Si-N bonds to (Si-N+Si-C) bonds is 0.4:0.5:0.9:1 for the Si–C–N films prepared with 5, 10, 15 and 20 sccm nitrogen flow rate, respectively