Fabrication of barium titanate thin films by potentiostatic electrochemical deposition

BaTiO3 thin films were prepared on Pt/Ti/SiO2/Si substrates in a water-meth yl alcohol mixed bath, nearly saturated with barium nitrate, by potentiosta tic electrochemical deposition. Weights and compositions of the as-grown fi lms were controlled by regulating electrochemical parameters such as the el ectrode potential, the quantity of electricity, and the concentrations of T i (IV) peroxo complexes in the electrolysis bath. Ba/Ti ratios in the as-gr own films were constant along the depth direction. No impurity in the as-gr own films was detected. The as-grown films were amorphous, and Ba2+ ions in them were present mainly as barium nitrate. Polycrystalline BaTiO3 thin fi lms were obtained by annealing above 500 degreesC for 1 h in air. The BaTiO 3 thin films were crystallized at a relatively low temperature of approxima tely 500 degreesC due to easy decomposition of barium nitrate to barium oxi de and nitrous gas during annealing.