Microstructure of columnar-grained SrTiO₃ and BaTiO₃ thin films prepared by chemical solution deposition

The microstructure and lattice defects of SrTiO₃ and BaTiO₃ thin films with columnar grains prepared by a chemical solution deposition technique have been investigated by means of transmission electron microscopy. The columnar grains in the SrTiO₃ films exhibit a preferential orientation with a crystallographic 〈111〉 direction parallel to the normal of film, which, in turn, follows the orientation texture of the substrate Pt layer. Cubic-to-cubic relationships have been found for the two materials. For the BaTiO₃ films the columnar grains are oriented in a random way without any preferential relationship to the substrate Pt layer. Pores, lattice defects, and grain boundaries occur in either type of film, however in different configurations. This reflects the individual nature of the materials and the different formation and growth mechanisms of the films under the preparation conditions.