SrxBi2.4Ta2O9 ( 0.7 less than or equal to x less than or equal to 1.3) thin films were processed by metalorganic decomposition and their ferroelectric characteristics were investigated. The Sr-deficient SrxBi2.4Ta2O9 films exhibited well-developed ferroelectric hysteresis curves compared to those of the Sr-excess films, and Sr0.85Bi2.4Ta2O9 film had the optimum electrical characteristics among SrxBi2.4Ta2O9 films. Electrical characteristics of the Pt/SBT/Al2O3/Si structure using Sr0.85Bi2.4Ta2O9(SBT) film were investigated for metalferroelectric- insulator-semiconductor field-effect-transistor (MFIS-FET) applications. Memory window of C-V hysteresis characteristics of the Pt/SBT/Al2O3/Si structure became large with decreasing the Al2O3 thickness, and the Pt/SBT(400 nm)/ Al2O3 (10 nm)/ Si structure gave memory window of 2.2 V at sweeping voltages of +/- 5 V. The Pt/SBT/Al2O3/Si structure can be proposed for MFIS-FET applications. (C) 2003 Kluwer Academic Publishers.