Characterization of magnetron sputtered carbon nitride films

A set of carbon nitride samples has been prepared by reactive magnetron sputtering. The only parameter varied was the nitrogen partial pressure p(N2). It turns out, however, that p(N2) has noticeable influence on the composition and the structure of the films only below 0.1 Pa. The composition of the bulk of the samples was investigated by elastic recoil detection (ERD), energy dispersive X-ray analysis (EDX), wavelength dispersive X-ray analysis (WDX) and Rutherford backscattering (RBS); although all of them give the same trend, some systematic differences were observed concerning the absolute values. Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) measurements revealed that the surface is somewhat depleted in nitrogen. Sputter depth profiling could not be applied due to very strong preferential sputtering of nitrogen. X-ray diffraction (XRD) showed that the films are almost amorphous. Structural information was obtained from Fourier transform infrared spectroscopy (FTIR), EELS, and XPS; it turned out that the films are graphitic or paracyanogen-like with a density of approx. 2 g cm(-3). All of the characterization methods applied are discussed in view of the information they yield on carbon nitride films, and problems of their application to this special type of film. (C) 1999 Elsevier Science S.A. All rights reserved.