A comparative study of elastic recoil detection analysis (ERDA), electron energy loss spectroscopy (EELS) and X-ray photoelectron spectroscopy (XPS) for structural analysis of amorphous carbon nitride films

Abstract

A set of carbon and carbon nitride films has been prepared by ion-beam-assisted filtered cathodic vacuum arc deposition. The films were examined by elastic recoil detection analysis (ERDA), electron energy loss spectroscopy (EELS) and X-ray photoelectron spectroscopy (XPS). ERDA provides the stoichiometry and mass density of the samples. This study covers the range of 0 up to 29 at.% N and 2.9 g cm −3 down to 2.0 g cm −3 respectively. The carbon K-edge and the plasmon loss were examined by EELS. The C 1s and N 1s core level spectra were recorded by XPS. The main result is that for significant nitrogen contents the mass density, and hence the plasmon energy and very likely the sp 3 -fraction, is reduced considerably. The C 1s signals of the carbon nitride layers show a multi-peak structure but the peaks are rather broad and an accurate determination of peak positions is not possible. The splitting of the N 1s signal in four contributions at about 398, 400, 400.6 and 402 eV is observed only for the low density carbon nitrides. A CN x sample with a density of 2.6 g cm −3 and equal amounts of sp 2 - and sp 3 -bonded carbon shows only a single peak. We show that the components in the N 1s multi-peak structure can be related to atomic arrangements in a fully sp 2 -bonded network. In particular, the component at 398 eV does not necessarily indicate the presence of a material similar to β-C 3 N 4 .