Leakage properties of BaTiO3 thin films on polycrystalline Ni substrates grown by polymer-assisted deposition with two-step annealing

Ferroelectric BaTiO3 (BTO) thin films were successfully deposited on nickel substrates by a chemical solution deposition technique named polymer-assisted deposition. A NiOx buffer layer and a first annealing in a reducing environment were adopted to control the interdiffusion and oxidation of the substrates. It was found that a second annealing in oxygen using a rapid thermal annealing furnace would strongly affect the electrical properties of the BTO thin films, especially the leakage current density. The leakage current density with the optimized annealing condition can be reduced by about two orders of magnitude. The correlation between the second annealing conditions and leakage current densities was established. Mechanisms of the leakage and impacts from the oxygen vacancies and interface evolution have been discussed.