Deposition and properties of highly (100)-oriented barium titanate thin films on LaNiO3 electrode

Highly crystallized and (100)-oriented barium titanate thin films having a composition of Ba(Zr0.12Ti0.88)O3 (BZT) were deposited on (100)-textured LaNiO3 electrode by rf magnetron sputtering at temperature from 300 to 550°C. The films had a very flat interface which was epitaxially bonded to the LaNiO3 electrode. However, the film deposited on Pt electrode was only weakly crystallized and had a rugged film/electrode interface. Satisfactory dielectric constant of value around 220∼270 was achieved for the films of 50 nm thick when deposited on LaNiO3 electrode at temperatures of 400∼550°C, while a much lower dielectric constant was obtained for that deposited on Pt electrode. More importantly, the films showed a very good insulating characteristic against biasing voltage, i.e. a low leakage current density, ⩽ 10−9 A/cm2, was maintained before reaching an onset voltage as high as ∼5 V, as compared to the film deposited on Pt electrode. It was also found that the current emission of the BZT thin films deposited on LaNiO3 followed the relation of Schottky emission, and a high Schottky barrier of 0.73 eV was evaluated from the temperature dependance of current emission.