ANALYTICAL ELECTRON-MICROSCOPY AND RAMAN-SPECTROSCOPY STUDIES OF CARBON NITRIDE THIN-FILMS

Deposition of carbon nitride thin films on Si(1000 and polycrystalline Zr substrates was performed by dc magnetron sputtering of a graphite target under a pure nitrogen ambient. The resulting carbon nitride films (CN(x)) are primarily amorphous with a small volume fraction of nanocrystallites. Both energy-dispersive x-ray analysis and electron energy loss spectroscopy measurements showed that the amorphous matrix has uniform nitrogen-to-carbon ratios approximately 0.4-0.8 depending on deposition conditions. Carbon and nitrogen K edge structures obtained from electron energy loss spectroscopy studies suggest that the amorphous carbon nitride matrix is primarily sp2 bonded. Apart from the carbon-nitrogen stretching vibration, Raman spectra of CN(x) films closely resemble those of diamondlike carbon films. Intensity and peak width changes of Raman features in the 1300-1600 cm-1 range due to inorganic carbon (D and G peak) under different deposition conditions are explained in terms of the extent of structural disorder in these films.