The seeding effect on the crystallization behaviors of the SrBi2Ta2O9 strontium bismuth tantalite (SBT) phase on top of a thin Aurivillius buffer layer, SrBi2Ta2xO9, was studied. A uniform microstructure and a preferred polar a-axis orientation within the SrBi2Ta1.8O9 buffered SrBi2Ta2O9 thin film were promoted to achieve a high remanent polarization (2P(r)) value of about 19.7 mu C/cm(2). Furthermore, the SBT/buffer heterostructure constructed by the two-step process showed a significantly improved leakage property compared with the nonbuffered SBT. The off-stoichiometric thin buffer layer demonstrates a simple method to improve the microstructure, polar a-axis orientation, and electric characteristics and to introduce less defects in the superposed SrBi2Ta2O9 thin films.