Polarization retention characteristics of ferroelectric SrBi2Ta2O9 (SBT) thin films prepared by metallorganic chemical vapor deposition (MOCVD) with and without Bi2O3 buffer layers on Pt/Ti/SiO2/Si substrates have been investigated. The retention loss of Pt/SBT/Pt capacitor is larger than that of Pt/SBT/Bi2O3/Pt capacitor. The polarization of Pt/SBT/Pt and Pt/SBT/Bi2O3/Pt capacitors at 3 x 10(4) s showed a loss of approximately 9 and 6%, respectively. In SBT films with a Bi2O3 buffer layer, both the second phase and the bismuth deficient layer were not formed at the interface between the SBT films and Pt bottom electrode. SBT films with a Bi2O3 buffer layer have an excellent interface property, resulting in an improvement of retention properties of SBT thin films. (C) 2004 The Electrochemical Society.