Preferred orientation, phase formation and the electrical properties of pulsed laser deposited SrBi₂Ta₂O₉ thin films

Systematic studies on the preferred orientation, phase formation and the electrical properties of pulsed laser deposited SrBi₂Ta₂O₉ (SBT) have been performed. At a substrate temperature of 600°C, the film on SiO₂ was not crystallized. Above 650°C, very strong diffraction from a non-ferroelectric, (III)-oriented fluorite phase was obtained. Its crystallinity increased with increasing Bi content in the target. The fluorite phase was also observed in the film on Pt deposited below 600°C, which together with the pyrochlore phase resulted in the formation of an interfacial reaction product, Bi₂Pt. Above 650°C, the films tend to grow as the perovskite SBT phase with a c-axis orientation which is not the polarization axis. In contrast, the formation of the fluorite and pyrochlore phases can be suppressed on Ir electrodes.