XPS studies of amorphous SiCN thin films prepared by nitrogen ion-assisted pulsed-laser deposition of SiC target

Amorphous SiCN films were prepared on Si (100) substrates by nitrogen ion-assisted pulsed-laser ablation of an SiC target. The dependence of the formed chemical bonds in the films on nitrogen ion energy and the substrate temperature was investigated by an X-ray photoelectron spectroscopy (XPS). The fractions of sp² CC, sp³ CC, and sp² CN bonds decreased, and that of NSi bonds increased when the nitrogen ion energy was increased without heating during the film preparation. The fraction of sp³ CN bonds was not changed by the nitrogen ion irradiation below 200 eV. Si atoms displaced carbon atoms in the films and the sp³ bonding network was made between carbon and silicon through nitrogen. This tendency was remarkable in the films prepared under substrate heating, and the fraction of sp³ CN bonds also decreased when the nitrogen ion energy was increased. Under the impact of high-energy ions or substrate heating, the films consisted of sp² CC bonds and SiN bonds, and the formation of sp³ CN bonds was difficult.