CHARACTERISTICS OF BISMUTH LAYERED SRBI2TA2O9 THIN-FILM CAPACITORS AND COMPARISON WITH PB(ZR,TI)O-3

We have developed the series of thin-film bismuth layer structured ferroelectric (BLSF) materials such as SrBi2 Ta2O9, SrBi2Nb2O9, SrBi4Ti4O15 and their solid solutions using metallo-organic-decomposition (MOD) spin-on coating techniques. We found that SrBi2Ta2O9 is one of the best potential candidate materials for ferroelectric nonvolatile memories. The SrBi2Ta2O9 thin-film capacitor had the remanent polarization (P-r+-P-r-) of 20 mu C/cm(2), coercive field of 35 kV/cm and dielectric constant of 250. SrBi2Ta2O9 thin him on platinum electrode has fatigue-free characteristics for up to 2 x 10(11) cycles without requiring any complicated electrode system such as conductive oxide. Moreover, SrBi2Ta2O9 thin film has many advantages, e.g., high signal/noise ratio of 8 at 1.2 V, low-voltage operation at as low as 1 V, long data-retention, little surface effect, superior imprint properties and low leakage current. We considered that these advantages are due to (1) less space Charge and (2) the inherent domain motion.