XPS Analysis of Titanium Nitride and Zirconium Nitride Compound Thin Layer Formed by Nitrogen Ion Implantation

Chemical state analyses of nitride layers in polycrystalline Ti and Zr produced by high dose implantation of nitrogen ions were performed by X-ray photoelectron spectroscopy (XPS). From the results, it was found that the accompanying the nitrogen ion implantation, a shift in the peaks of the Ti 2p3/2 or the Zr 3d5/2 spectra occurred, and that the magnitude of the binding energy shift became the largest in the vicinity of the maximum concentration of nitrogen. The magnitude of the shift was nearly equal to that of the MeN1.0 thin films formed under the equilibrium condition. The change in the binding energy difference between the Ti 2p3/2 and the N 1s core peaks shifted to the high-energy side along with the increase of the nitrogen concentration. At a nitrogen concentration of about 30%, a clear inflection point was observed. It was shown that this inflection point corresponds to the stoichiometric change from Ti2N to TiN1.0. The N 1s-Zr 3d5/2 binding energy difference values showed a nearly constant value of 218.3eV in the low concentration region where the nitrogen atoms are α-phase, and it became clear that they decreased continuously from the region for forming ZrNx (25 at. %N). It was understood that the change in the binding energy shows a change in the electron charge transfer from metals to nitrides accompanying an increase in the nitrogen atom concentration. The possibility that nitride thin layers having a gradient composition of nitrogen atoms in the depth direction can be formed was suggested.