Carbon-K NEXAFS measurements of a-CNx films formed from decomposition of BrCN in electron cyclotron resonance plasmas of He, Ne, and Ar

Amorphous carbon nitride (a-CNx) films were formed from the decomposition of BrCN in the electron cyclotron resonance plasmas of He, Ne, and Ar. The local structures of these films were investigated by the carbon-K near edge X-ray absorption fine structure. It was found that the density of C=C bond in the film prepared with Ar plasma was 7–9 times larger than that with He or Ne plasmas. The [N]/([C] + [N]) ratios of films were estimated from the X-ray photoelectron spectra as 0.34 ± 0.05, 0.35 ± 0.04, and 0.28 ± 0.05 for the He, Ne, and Ar plasmas, respectively. It was found that C atoms in the sp2-hybridized state were incorporated into the two-dimensional and/or one-dimensional conjugated structures composed of − C=N− in the cases of the He and Ne plasmas and of − C=C− in the case of the Ar plasma. The compositions and the local structures of films can be explained in terms of a model based on the cyclazine-like network structures.