Pulsed laser ablation synthesis and ferroelectric properties of SrBi₂Ta₂O₉ thin films

Ferroelectric SrBi₂Ta₂O₉ (SBT) thin films were synthesized on Pt/Ti/SiO₂/Si substrates using pulsed laser deposition combined with annealing technique, and structural and electrical properties were investigated. The SBT thin films with fine grain size and well-saturated square hysteresis loop was obtained. The films showed high diffraction peaks of (115) and (008). A dense structure with around 200 nm grain size was observed using the scanning electron microscope (SEM). Good ferroelectric properties were obtained from the films; Pr and Ec were 8.4μC/cm² and 57kV/cm, respectively. No fatigue was observed up to 10¹⁰ switching cycles. I-V characteristic showed the two peaks at the coercive voltage. It has a 560pF capacitance and a static dielectric constant of 600 at zero applied voltage from the I-V characteristic. These properties are very attractive for nonvolatile memory application.