Improvement of the thermal stability of amorphous carbon films by incorporation of nitrogen

Nitrogenated amorphous carbon films have been deposited by dual-facing-targ et sputtering, and their thermal stability has been investigated by means o f X-ray diffraction (XRD), Raman spectroscopy (RS) and X-ray photoelectron spectroscopy (XPS). The XRD analyses indicate a slower graphitization proce ss in the CN films during annealing in comparison with the amorphous C film s. The Raman measurements show that the sp(2) concentration increases throu gh nitrogen incorporation, which in turns leads to a smaller layer expansio n after annealing. Conductivity measurements further confirm this suggestio n. The XPS results give the information of the existence of the strong cova lent bonding between N and C atoms, which can slow down the tendency of the structural relaxation during annealing. The effect of nitrogenation on the formation of sp(3) bond is discussed tentatively in terms of coordination. These results suggest that the thermal stability of amorphous C films can be improved by N incorporation through reactive dual-facing-target sputteri ng. (C) 1999 Elsevier Science S.A. All rights reserved.