Influence of Bi2O3 in the microstructure of SrBi2Ta2O3 films deposited by pulsed laser ablation

A systematic study of the microstructural features of SrBi2Ta2O9 (SBT) film s prepared on Pt(111)/TiO2/SiO2/Si by pulsed laser deposition (PLD) and hea t treated at different temperatures, is presented. The films heat treated d uring deposition have a temperature-induced preferential growth in the (1 1 5) orientation and reach the SBT crystal structure at 600 degreesC, free f rom undesired secondary phases. From transmission electron microscopy and X -ray diffraction analysis, the morphology of the SBT and the Bi2O3 crystals in the films are determined. Additionally, the non-oriented polycrystallin e growth and the development of cracks in films deposited at the lowest tem perature (300 degreesC) and then annealed at high temperatures are explaine d. It is seen in these films that once the Bi2O3 crystal phase is eliminate d during the post-annealing process, the growth of the SBT crystals is line ar at a rate of of 0.8nm\degC(-1). It is proposed, as a result of these stu dies, that a deposition temperature of at least 600 degreesC should be used to avoid the presence of crystalline Bi2O3 and cracking during the post-an nealing treatment. (C) 2001 Kluwer Academic Publishers.