Sol–gel synthesis and property studies of layered perovskite bismuth titanate thin films

Layered perovskite bismuth titanate (BTO) thin films were deposited on platinum coated silicon substrates by spin coating. A homogeneous and stable precursor solution was prepared by sol–gel process using bismuth nitrate and titanium(IV) butoxide as starting materials, glacial acetic acid and ethanolamine were selected as solvent and stabilizing agent, respectively. The crystal structure, surface morphology, composition and electrical properties of the films have been investigated. Crystal structure and morphology of the films are strongly influenced by the heat cycle adopted to form crystalline BTO films. Morphology of the films studied by AFM is found to be smooth, dense, and crack free. The deposited films possess good compositional homogeneity and thickness uniformity. The dielectric constant and the dissipation factor measured at 1 kHz at room temperature are found to be 135 and 0.018, respectively, for the films of 0.4-μm thickness annealed at 600 °C for 1 h. The remnant polarization and coercive field values are estimated to be 5 μC cm−2 and 45 kV cm−1. The films possess good fatigue properties and useful for application in the non-volatile memories.