Dielectric characteristics of barium strontium titanate films prepared by aerosol deposition on a Cu substrate

Polycrystalline barium strontium titanate (Ba_xSr_1-xTiO₃, BST) films were directly prepared on copper substrates using an aerosol deposition method (ADM) at room temperature. Electric properties, such as the dielectric constant and tunability, were investigated as a function of the Ba content in Ba_xSr_1-xTiO₃ (x = 1.0, 0.6, 0.4) films. At a frequency of 100 kHz, the dielectric constant of the as-deposited BST films were 100, 201, and 72 for x = 1.0, 0.6, and 0.4, respectively. After annealing in N₂ at 500degC, the dielectric constant of the films on Cu electrodes were 190, 400, and 170 at x = 1.0, 0.6, and 0.4, respectively. Moreover, the BST (x = 0.6) film showed a high tunability of 30% under an applied electric field of 300 kV cm^-1.