NITROGEN-ION IRRADIATION DURING THE DEPOSITION OF C1-XNX THIN-FILMS BY ION-BEAM SPUTTERING TECHNIQUE

The morphology of the carbon nitride (C1-xNx) thin films deposited by the reactive ion beam sputter deposition technique has been studied. A pure graphite target has been sputtered using nitrogen ions. Some of the deposited films have been irradiated with the primary nitrogen ion beam during the deposition. The films were prepared at room temperatu re on the crystalline Si substrates. The IR absorption spectrum of the C1-xNx film irradiated with lower energy (0.6 keV) ions has an absorp tion band that peaked at 1550 cm(-1), which has been attributed to the graphitic sp(2)-bonded carbon (G band) in the study of Raman spectros copy, while the nonirradiated film which was deposited with a 0.6 keV beam has shown neither a G band nor a D band corresponding to the diso rdered sp(3)-bonded carbon in the IR spectra. On the other hand, the f ilms irradiated with a higher energy (1.0 keV) ion beam have shown a v ery broad ''D-band'' IR spectrum in the IR range between 1000 and 1700 cm(-1). The x-ray photoelectron spectroscopy spectra indicate that al l films contain nearly equal quantities of the C=N triple and C=N conj ugated double bonds, while the LR absorption peaks attributed to the C =N stretching mode are larger in the ion-irradiated samples than in th e nonirradiated ones. These results suggest that sputtering by and/or irradiation of a higher energy ion beam contribute to form termination s of the diamondlike carbon network, which contains pyridinelike struc tures, in the form of cyano-radicals since the absorption peak due to the C=N stretching mode is enhanced when cyano-radicals bond with a co njugated system in the neighboring sites. (C) 1996 American Vacuum Soc iety.