Tetrahedral amorphous carbon (ta-C) and nitrogenated tetrahedral amorphous carbon films (ta-CNx), deposited by double bend off plane Filtered Vacuum Cathodic Arc were annealed up to 1000 degrees C in flowing argon for 2 min. Modifications on the chemical bonding structure of the rapidly annealed films, as a function of temperature, were investigated by NEXAFS, X-ray photoelectron and Raman spectroscopies. The interpretation of these spectra is discussed. The results demonstrate that the structure of undoped ta-C films prepared at floating potential with an arc current of 80 A remains stable up to 900 degrees C, whereas that of ta-CNx containing 12 at.% nitrogen is stable up to 700 degrees C. At higher temperatures, all the spectra indicated the predominant formation of graphitic carbon. Through NEXAFS studies, we clearly observed three pi* resonance peaks at the N K edge structure. The origin of these three peaks is not well established in the literature. However our temperature-dependant study ascertainedthat the first peak originates from C=N bonds and the third peak originates from the incorporation of nitrogen into the graphite like domains. (c) 2004 Elsevier B.V. All rights reserved.
Bibliographical noteSymposium on Synthesis, Characterisation and Advanced Application of Amorphous Carbon Films, Strasbourg, FRANCE, MAY 24-28, 2004
- amorphous carbon films
- carbon nitride
- X-ray spectroscopy