Nucleation and grain growth of SrBi2Nb2O9 thin films

Abstract

Bi-layered perovskite SrBi2Nb2O9 (SBN) thin films have been deposited on Si (100) substrates by metalorganic decomposition technique. The SBN thin films were post-annealed at 700degreesC in a pre-heated annealing condition for the investigation of crystallization processes. A high-resolution transmission electron microscopy study showed a nucleation process and a grain growth mechanism of the SBN thin films from a fluorite-like phase to a Bi-layered perovskite phase. In an initial stage of the nucleation process, adjacent 10 nm-sized fluorite-like grains that were slightly misaligned were phase-transformed to a Bi-layered perovskite grain, when a lot of defects such as antiphase boundaries (APBs) were induced due to a little misalignment of the adjacent grains. After a further annealing process, the grain size of the Bi-layered perovskite phase becomes about 0.2-0.3 mum and many defects such as APBs have considerably diminished. This grain growth behavior is totally different from a conventional elliptical growth model, which occurred at the point of a grain growth mechanism and a change of the grain shape. Moreover, the surface morphology of the SBN thin film was remarkably improved compared with that of the elliptically grown SBN thin films. (C) 2003 Elsevier B.V. All rights reserved.