Comparison of the X-ray photoelectron and electron-energy-loss spectra of the nitrogen-doped hydrogenated amorphous carbon bond

The composition of nitrogen-doped hydrogenated amorphous carbon (a-C: H: N) films grown in a magnetically confined rf plasma-enhanced chemical vapour deposition system has been determined by X-ray photoelectron spectroscopy (XPS) and compared with that determined using a combination of elastic recoil detection analysis, Rutherford back-scattering. and nuclear reaction analysis. The importance of nitrogen doping or 'incorporation' in hydrogenated amorphous carbon (a-C:H) films is discussed in relation to the significant variation in the sp(2)-to-sp(3) ratio that takes place. At 7 at.% N in the a-C: H matrix, a critical change in the microstructure is observed, which governs the resulting mechanical, optical and electronic properties. Finally, the correlation between the sp(2) and sp(3) fractions determined by a non-destructive method of obtaining the bond fractions (XPS) and by electron-energy-loss spectroscopy is discussed, with a view to evaluating accurately the sp(2) fraction in a-C: H: N films.