Cryogenic deposition of carbon nitride films using a neutralized atomic nitrogen beam

Abstract

Thin carbon nitride CN x films were successfully prepared by co-deposition at cryogenic temperatures, ranging from 20 to 80 K, of fullerene C 60 or cyanogen with energetic neutralized atomic nitrogen fluxes under initial ion beam energies varied from 200 to 700 eV. Film growth rates in excess of 1 μm h −1 and stoichiometries ranging from almost pure C to above 40 at.% N were formed. Film hardness and adherence were good for films with approximately 20 at.% nitrogen while higher nitrogen concentrations yield cyano-rich, soft films. The Fourier transform infrared, Raman and X-ray photoelectron spectra showed the predominantly sp 2 character of the chemical bonding between nitrogen and carbon in the films containing 29–37 at.% N, and suggest an amorphous graphite-like structure for the carbon nitride C 3N 4 phase present along with graphitic carbon as a by-product in the films prepared by cryodeposition onto Si substrates. X-Ray diffraction and scanning electron microscopy studies did not indicate the presence of any crystalline carbon nitride polymorphs in the film.