Structural and electrical characteristics of rapid thermally processed ferroelectric Bi4Ti3O12 thin films prepared by metalorganic solution deposition technique

Abstract

Polycrystalline Bi4Ti3O12 thin films having layered perovskite structure were fabricated by metalorganic solution deposition technique on both Pt-coated Si and bare Si substrates at a temperature as low as 500 °C. The effects of post-deposition rapid thermal annealing on the structural and electrical properties were analyzed. The electrical measurements were conducted on metal–ferroelectric–metal capacitors. The typical measured small signal dielectric constant and dissipation factor at 100 kHz were 184 and 0.018 and the remanent polarization and the coercive field were 4.4 μC/cm2 and 84 kV/cm, respectively. The films exhibited high resistivity in the range 108–1012 Ω cm for films annealed at temperatures of 500–700 °C for 10 s. The I–V characteristics were found to be Ohmic at low fields and space-charge-limited at high fields. A V3/2 dependence of the current was observed in the space-charge region. This could be explained by assuming the mobility to be field dependent since in thin films the electric fields are invariably high even at low applied voltages.