Structural and dielectric properties of calcium doped bismuth zinc niobate thin films prepared by pulsed laser deposition at room temperature

(Bi_1.5Zn_0.1Ca_0.4)(Zn_0.5Nb_1.5)O₇ (BZNCa) thin films were prepared by pulsed laser deposition on Pt/TiO₂/SiO₂/Si substrates at room temperature. The as-deposited films and films post-annealed from 100 °C to 175 °C for 10 min in air are all amorphous. The influence of the post-annealing process on structural and electrical properties was investigated. The surface morphology of BZNCa films remains almost same with the annealing temperature. While the dielectric and leakage-current properties of the films are strongly influenced by the annealing temperature. The film deposited at O₂ pressure of 4 Pa and then post-annealed at 150 °C shows the improved dielectric and leakage-current characteristics. The dielectric constant and loss tangent are 67.2 and 0.03 at 100 kHz, respectively. The leakage current density is less than 1 μA/cm² at an applied bias electric field of 400 kV/cm. The results indicate that calcium doped BZN thin films have potential applications for embedded capacitors.