Electrical properties and thermodynamic stability of Sr(Ti1-x,Ru-x)O-3 thin films deposited by inductive-coupling-plasma-induced RF magnetron sputtering

Sr(Ti1-xRux)O-3 (STRO) epitaxial thin films were deposited on single-crysta l SrTiO3(100) substrates using the inductive-coupling-plasma-induced RF mag netron sputtering method without oxygen. The electrical conductivity of STR O films increases with Ru concentration and levels of the Ru 4d states are observed in the band gap of SrTiO3 by X-ray photoelectron spectroscopy (XPS ) analysis. These results are consistent with those obtained by first-princ iples calculations. Thermodynamic stability increases with the decrease of Ru concentration, and STRO (x < 0.50) is free from degradation under anneal ing H-2 atmosphere at 600 degreesC. This high resistance against reductive processes indicates that STRO (x < 0.50) is one of the most suitable candid ates for conductive oxide electrodes of oxide capacitors.