Carbon nitride CNx film deposition assisted by IR laser ablation in a cold remote nitrogen plasma

Abstract

Thin films of carbon nitride CNx were prepared on a non-heated substrate in the pressure range 100-1000 Pa. Carbon nitride films were deposited by ablation of carbon molecular fragments from a graphite or pyrocarbon target onto a silicon substrate after a few pulses of a localized transversely excited atmospheric pressure (TEA) CO2 laser. The deposition medium was either a gaseous flow of pure nitrogen or nitrogen-helium mixtures or cold remote plasma of nitrogen (CRNP) or of nitrogen-hydrogen mixtures (CRNPH). Fourier transform IR (FTIR) spectra of the deposited films show a very efficient nitrogen fixation with C-N bands characteristic of tetrahedral carbon. These results are confirmed by Raman spectroscopy. X-ray photoelectron spectroscopy of samples typically shows two peaks in the N Is core level spectrum (centred at 399.4 and 400.8 eV). The effect of the distance of the deposition zone from the discharge is also discussed. The plasma created around the target is studied by UV-visible optical emission spectroscopy (OES). Gas phase results are correlated with the characteristics of the deposits. © 1997 Elsevier Science S.A.