Electrical properties of (Ba,Sr)TiO3 on (Sr,Ca)RuO3 electrode

A perovskite (Sr,Ca)RuO3 [SCR] electrode has been explored in order to utilize its advantages in structural match with (Ba,Sr)TiO3 [BST] films, which may enhance the electrical properties of BST films. The SCR electrode led to the leakage current density (10−7 A/cm2) of BST films an order lower than that on RuO2. The leakage current was not sensitive to the composition of the SCR electrodes, while the dielectric constant of the BST thin film capacitor ranged from 160 to 280 depending on the Sr/Ca ratio in SCR electrodes. The BST/SCR (Sr/Ca = 7/3) system resulted in a 5–nm thick interfacial layer. Furthermore, the interfacial layer turned out to be partially crystallized according to the lattice image taken by an HRTEM. It is believed that such enhancement in electrical properties of BST films could be induced by the improvement of interfacial characteristics through structural matching.