Electrical properties of ferroelectric SrBi₂Ta₂O₉ thin films deposited on MOCVD-Pt/SiO₂/Si substrates by plasma-enhanced metalorganic chemical vapor deposition

Abstract
The SrBi₂Ta₂O₉ thin films were prepared on MOCVD-Pt/SiO₂/Si substrates at 550°C by plasma-enhanced metalorganic chemical vapor deposition. Platinum bottom films deposited by metalorganic chemical vapor deposition (MOCVD) showed a dense and stable state after deposition of SBT films and grains of SBT films show a rectangular shape. The SBT ferroelectric capacitor shows practically no polarization fatigue after the sarnple was switched up to 7.0 x 10⁹ cycles. The retention characteristics of the SBT films looked very promising up to 10⁵ sec and the charge loss for 10 years was estimated to be 10% at room temperature. The leakage current density of the SBT films was about 4 x 10^-7 A/cm² at an applied electric field of 250 kV/cm. The leakage current behavior of SBT films was controlled by a Schottky emission and the schottky barrier height of SBT films was about 0.8 eV.