Leakage Mechanisms Of BaTiO₃ Thin Films On Nickel Substrates Fabricated Using Polymer-assisted Deposition Technique Research

We made BaTiO3 thin films on Ni substrate by using polymer assisted deposition(PAD).It’s leakage Current has been tested and analyzed respectively. We have used Frankel- Pool emission, Space Charge Limited Current(SCLC) and Schottky emission to describe BTO thin film leakage mechanism. We got the structure characteristics of the film and the band diagram. Get BTO film internal mainly oxygen vacancy defect ionization electron as the main carrier of BTO/Ni interface for oxidative decomposition of buffer layer of nickel and nickel base board and the diffusion of BTO film ohmic contact. It was obtained by computing the electron mobility about 0.001cm2/Vs, concentration of carrier in the thin film about Nt = 1.222 x 1015 / cm3,impurity level for Ec- Et = 0.26 eV, thus we determined internal defects of BTO thin film were mainly oxygen vacancies. Under the negative voltage leakage mechanism was schottky conductive mechanism. According to the formula of Schottky emission mechanism, the effective barrier of Au/BTO interface is 0.30 eV. A first-order linear circuit model was used to analyse the film, by testing its J- t curve, thin film resistance is calculated with the size of the body resistance and the voltage change trend and get the result is consistent with the experimental and theoretical. First made oxygen atoms get into films, exist in the form of ions, then made oxygen into the lattice under the protective gas, avoid nickel substrate be oxidized, and at the same time reduce the leakage current. Nickel oxide buffer layer will be decomposed into metallic nickel and oxygen in the preparation of BTO thin films. The oxygen can be used to reduce the oxygen vacancy. The film doped with extra Ti will have a small leakage current and a better dielectric property. The redundant Ti exists in the film as the form of Ti O2.