The effect of annealing temperature on the formation of SrBi/sub 2/Ta/sub 2/O/sub 9/ (SBT) thin films

In this paper we report on synthesis of SBT thin-films by sol-gel processing. Sr metal, Bi, 2-ethyl hexanoate and Ta-ethoxide were used as precursors. Thin-films with nominal composition SrBi/sub 2/Ta/sub 2/O/sub 9/ and SBT +10% excess Bi content were made. Films were annealed at various temperatures to study the microstructure, crystallization temperature and the polarization values. Good crystallization of SBT was obtained by annealing at 700/spl deg/C-2 hrs, independent of the Bi content in the films. Films annealed in oxygen atmosphere at 800/spl deg/C-2 hrs did not show any significant change in the polarization value. Crack free films were made with film thicknesses of 0.4 /spl mu/m. Films annealed at 800/spl deg/C-2 hrs showed a grain size of /spl sim/0.2 /spl mu/m, and reasonably good polarization values of 5 /spl mu/C/cm/sup 2/. In contrast, films prepared with 10% excess Bi showed a very fine grain size <0.1 /spl mu/m with a lower polarization values of 1.5 /spl mu/C/cm/sup 2/.