Ba0.7Sr0.3TiO3 ferroelectric film prepared with the sol-gel process and its dielectric performance in planar capacitor structure

Ferroelectric Ba0.7Sr0.3TiO3 thin films were successfully deposited on sapphire (r-cut) substrates by the sol-gel process, and the deposited films were annealed at various temperatures and for various soaking times. The compositional and structural characteristics of the films were systematically examined with the aid of x-ray diffraction, scanning electron microscopy, and medium energy ion scattering techniques. Their dependence on thermal processes was investigated. A planar capacitor structure based on the BSTO films was fabricated to evaluate the electrical and dielectric performance. These results, together with the microstructure characteristics, were analyzed and an optimal process was finally established.