Ferroelectric properties of face-to-face annealed Sr/sub 0.8/Bi/sub x/Ta/sub 2/O/sub 9/ thin films

Ferroelectric and insulating properties of sol-gel-derived and face-to-face annealed strontium bismuth tantalate (SBT) thin films were investigated, in which the precursor solutions in the form of Sr/sub 0.8/Bi/sub x/Ta/sub 2/O/sub 9/ were used and the x-value was changed from 2.0 to 2.4. The remanent polarization (2Pr) showed the maximum value at the Bi composition of 2.3. At this Bi composition, the 2Pr value of a face-to-face annealed SBT film crystallized at 750/spl deg/C was as large as 19.8 /spl mu/C/cm/sup 2/, while it was 16.7 /spl mu/C/cm/sup 2/ in a film without face-to-face annealing. It was also found from the time dependence of leakage current density that the minimum leakage current density of the face-to-face annealed SBT films at the Bi composition of 2.3 was lower than 1 nA/cm/sup 2/ at the electric field of 130 kV/cm.