Soft X-ray emission spectroscopy used for the characterization of a-C and CNx thin films

•CNx and a-C film densities decrease with the increase of thickness.•Density increases with the decrease of Si(100) substrate temperature at preparation.•Highest concentration of the diamond-like structure is in the substrate vicinity.•It reduces further from the substrate and stabilizes at thickness ≥ 2 nm.

We present the results of a soft X-ray emission spectroscopy study of a-C and CNx films on a Si(100) substrate. Also for the characterization of the homogeneity in depth of these films electron energy loss spectroscopy measurements with localization better than 4 nm were carried out. In case of CNx films the highest diamond-like modification occurs in the region close to the Si(100) substrate. The film density decreases with increasing distance from the substrate and becomes almost constant in range of thicknesses more than ~ 2 nm.