Interface analysis of HfO2 films on (1 0 0)Si using x-ray photoelectron spectroscopy

Thin layers of HfO2 grown on the (1 0 0)Si crystal surface using atomic layer deposition or metallo-organic chemical vapour deposition were analysed using x-ray photoelectron spectroscopy (XPS) of Hf 4f, Si 2p and O 1s electron states. The chemical indepth profiling was conducted by combining XPS with Ar+ ion sputtering. In addition to establishing the deposition-sensitive oxide structure, Ar+ ion sputtering was found to lead to the formation of a metallic Hf layer on the surface of the sample. The latter observation suggests HfO2 as a feasible candidate for not only insulating applications but, thanks to the high mass and electron density of the cation, also as a material suitable for the fabrication of nanometre-sized conductors by direct oxide decomposition.