Structural studies of reactive pulsed laser-deposited CNx films by X-ray photoelectron spectroscopy and infrared absorption

Abstract

The changes in the structure of reactive pulsed laser-deposited (RPLD) CN_x films with nitrogen content from 3.6–22 at% have been investigated by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Fourier transform–infrared (FT–IR) absorption. The films were found to be amorphous, and to consist of a network of rings. The rings that were composed solely of carbon atoms gave rise to an XPS peak located between 284.3 and 284.8 eV (C¹ component). The rings containing nitrogen led to another peak located between 285.5 and 286.4 eV (C² component). When the nitrogen content increased, the relative intensity of the C¹ component fell, while that of the C2 component rose, indicating that some carbon atoms in the rings were replaced by nitrogen atoms. C≡N bonds also contributed to the C² component. The FT–IR data were consistent with this interpretation. No evidence for the existence of a β-C₃N₄ phase was found in RPLD CN_x films.