Ferroelectric and microstructural characteristics of SrBi₂Ta₂O₉ thin films crystallized by the rapid thermal annealing process

Ferroelectric SrBi₂Ta₂O₉ thin films on Pt/Ti/SiO₂/Si were successfully synthesized by the modified polymeric precursor method. The films were deposited by spin coating and crystallized by rapid thermal annealing in a halogen lamp furnace, followed by postannealing at temperatures ranging from 700 °C to 800 °C in an oxygen atmosphere. Microstructural and phase evaluations were followed by x-ray diffraction and atomic force microscopy. The films displayed spherical grain structures with a superficial roughness of approximately 3–6 nm. The dielectric constant values were 121 and 248 for films treated at 700 °C and 800 °C, respectively. The P–E curve showed a voltage shift toward the positive side, which was attributed to crystallization under the halogen illumination. The remanent polarization (2P_r) and coercive field (E_c) were 7.1 μC/cm² and 113 kV/cm, and 18.8 μC/cm² and 93 kV/cm for the films treated at 700 °C and 800 °C, respectively. © 2001 American Institute of Physics.