Characterisation of carbon nitride thin films prepared by reactive magnetron sputtering Original Research Article

Carbon nitride (CNx) thin films have been obtained by reactive magnetron sputtering in a pure N2 discharge. The films have been characterised by Fourier transform infrared spectroscopy (IR), transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), X-ray photoelectron spectroscopy (XPS) and UV-vis absorption spectroscopy. A maximum value of NC = 0.5 has been achieved. Evidence is presented of the formation of a polymer-like CNx amorphous phase which contains CN, CN and CN bonds. A new peak at 286.5 eV energy loss in the C K-edge EELS spectra has been assigned to CN bonds with carbon in the sp2 hybridisation state. Infrared spectroscopy indicates that cyanogen-like groups are present in the films and can be partially removed by thermal annealing. The contribution of CN and CN bonds has also been determined by infrared and XPS spectroscopy.