Improvement in ferroelectric properties of SrBi2Ta2O9 thin films with Bi2O3 buffer layers by liquid-delivery metalorganic chemical-vapor deposition

Ferroelectric SrBi2Ta2O9 (SBT) thin films were deposited onto the Bi2O3 buf fered Pt/Ti/SiO2/Si substrates using liquid-delivery metalorganic chemical- vapor deposition. The SBT films with a 5-nm-thick Bi2O3 buffer layer on a P t bottom electrode showed (115) orientation stronger than those without the Bi2O3 buffer layer after annealing at 750 degreesC. The Bi2O3 buffer layer in Pt/Bi2O3/SBT/Bi2O3/Pt/Ti/SiO2/Si capacitors effectively prevents the ev aporation of Bi through the Pt top electrode and diffusion of Bi into the P t bottom electrode. The remanent polarization and leakage current densities of SBT films with Bi2O3 buffer layers were improved significantly in compa rison with those for the films without the Bi2O3 buffer layer. The remanent polarization (2P(r)) and coercive field (E-c) of SBT films without and wit h the Bi2O3 buffer layer annealed at 750 degreesC were 12 and 23 muC/cm(2), 57 and 38 kV/cm at an applied voltage of 5 V, respectively. (C) 2001 Ameri can Institute of Physics.