Evolution of electronic and atomic structure of amorphous Ta 2 O 5 during sputtering by Ar + ions was investigated by means of X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. XPS Ta 4f spectra were analyzed through spectral decomposition by paying special attention to inelastic scattered electron background subtraction from the Ta 4f spectra. The decomposition revealed the formation of Ta 4+ , Ta 3+ , Ta 2+ , Ta + , and Ta 0 chemical states during the sputtering. The dynamics of the Ta chemical states evolution was analyzed and referred to the modification of the local atomic structure revealed by the NEXAFS O K-edge absorption spectra analysis. The transformation of the O K-edge spectra during the sputtering suggests the preservation of a significant part of octahedrons (the structural units of stoichiometric amorphous Ta 2 O 5 ), which serve as a matrix for low-symmetry structural units transformed from the octahedra during the sputtering. Possible mechanisms of the octahedra transformation were discussed based on the O K-edge spectra and orbital correlation diagrams. It is noteworthy that the experiment showed a possibility of complete Ta metallization by Ar + ion bombardment of amorphous Ta 2 O 5 on the Si substrate.

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Chemical composition of interfaces between physical-vapor deposited TiN and SiO 2 as affected by introduction of a thin (0.5-3 nm) alumina interlayer was studied using photoelectron spectroscopy with high kinetic energies of photoelectrons (HAXPES) and near edge X-ray absorption fine structure (NEXAFS). Our results reveal formation of TiO 2 and titanium oxynitride phases both at the bottom interface of the TiN film and at its surface due to oxygen scavenging from the SiO 2 and oxidation in air, respectively. Insertion of alumina layer as thin as units of nm prevents the TiO 2 growth at the bottom TiN/SiO 2 interface but leads to formation of aluminosilicate layer. The thickness of this silicate layer practically independent on the thickness