Evaluation of tailored electrode (Ba,Sr)RuO3 for (Ba,Sr)TiO3

The conducting oxide electrode (Ba,Sr)RuO3 (BSR), which is expected to be advantageous for (Ba,Sr)TiO3 (BST) dielectric materials due to its similarity in structure and chemical composition, was evaluated. Ba/Sr and (Ba+Sr)/Ru ratios in BSR films were varied to investigate the effect of composition in BSR films on the BST properties. BSR films deposited at 1/9 ratio of O-2/Ar resulted in the lowest resistivity. BST films on stoichiometric BSR electrodes demonstrated the best electrical properties. The dielectric constant was 450 and the leakage current density was 10(-8) A/cm(2),which is about two orders of magnitude lower than BST on RuO2 processed in the same laboratory conditions. The dielectric constant of BST films was affected more by the chemical composition, while the leakage current was influenced both by the chemical composition and the lattice constant of BSR. Minimization of reaction at the interface between BST and BSR through a suppression of diffusion due to the compositional similarity seems to result in such outstanding electrical properties. (C) 1999 American Institute of Physics. [S0021-8979(99)01418-8].