Characterization of carbon nitride thin films deposited by microwave plasma chemical vapor deposition

The carbon nitride films have been prepared on Si substrates using microwave plasma chemical vapor deposition (MPCVD) technique. The experimental X-ray diffraction (XRD) spectra of films deposited on Si substrates appear to contain all of the strong peaks of α-C3N4 and β-C3N4, but there is considerable peak overlap, therefore the existence of these phases cannot, for certain, be claimed from this data. However, the N/C atomic ratio is close to the stoichiometric value 1.33. X-Ray photoelectron spectroscopy (XPS) analysis indicated that the binding energies of C 1s and N 1s are 286.43 and 399.08 eV, respectively. The shifts are attributed to the polarization of the CN bond. Both observed Raman and Fourier transform infrared (FT-IR) spectra were compared with the theoretical calculations. The results support the existence of a CN covalent bond in the films.