Characterization of thin Ta–Si–Nx layers of different nitrogen content using XPS, UPS and STM

Reactively sputtered Ta–Si–Nx barrier systems of different nitrogen content on copper were investigated by photoelectron spectroscopy (XPS, UPS) and scanning tunnelling microscopy (STM). The measured photoelectron spectra (excitation He–I) showed a clear dependence of the electron state density near the Fermi edge on the content of nitrogen. These results correlate with the I(U) characteristics of the STM measurements and the electrical conductivity of these layers.