Leakage current and breakdown behavior of bismuth-doped amorphous strontium titanate thin film

In this paper, the leakage current and breakdown behavior of amorphous Sr1-1.5xBixTiO3 (x = 0, 2, 5, 10 and 15 mol %) thin films in ambient air and a vacuum were studied firstly. The results showed that the leakage current and breakdown strength could be effectively affected by Bi doping. The leakage current decreased with the increase of Bi doping. The breakdown strength of all doped samples in air was close to that of the SrTiO3 film (189 MV/m). However, the breakdown strength was significantly enhanced in a vacuum. Typically, the breakdown strength of 5% Bi doped sample was up to 412 MV/m, about 2 times as high as that of the SrTiO3 sample (215 MV/m). It was explained in terms of the absorbed water, which was critical to the durability of the films. The effect of bismuth on the electric properties was validated by experimental J-E curves acquired for a broad range of applied electric field, where the suppression of ionic conduction and the additional traps-filling consecutively dominated in the low field (0-100 MV/m) and high field (100-400 MV/m) regions. These results indicate the potential of Bi-doped SrTiO3 thin film as high-energy density dielectric capacitors.