Electrical Properties and Thermodynamic Stability of Sr(Ti1-x,Rux)O3 Thin Films Deposited by Inductive-Coupling-Plasma-Induced RF Magnetron Sputtering

Sr(Ti1-x,Rux)O3 (STRO) epitaxial thin films were deposited on single-crystal SrTiO3(100) substrates using the inductive-coupling-plasma-induced RF magnetron sputtering method without oxygen. The electrical conductivity of STRO 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-principles calculations. Thermodynamic stability increases with the decrease of Ru concentration, and STRO (x<0.50) is free from degradation under annealing H2 atmosphere at 600°C. This high resistance against reductive processes indicates that STRO (x<0.50) is one of the most suitable candidates for conductive oxide electrodes of oxide capacitors.