Structures and properties of La- and Sm-doped BaTiO3 sputtered films: Post-annealing and dopant effects.

200-nm-thick La- and Sm-doped BaTiO3 thin films with A/B ratio of unity fabricated by magnetron sputtering on the Pt/Ti/SiO2/Si substrate have been characterized. The effects of post-annealing and the amount of dopant on structure and electrical properties were studied. X-ray diffraction studies reveal that the films annealed at 750 °C show tetragonal BaTiO3 crystal structure without any detectable second phase formation. X-ray photoelectron spectroscopy results confirm that La substitutes the A site and Sm is in the B site in lightly doped films. La2O3 or Sm2O3 is present in the BaTiO3 structure when the dopant content is more than 1.4 at. % La or 1.0% Sm. The permittivity increases with increasing annealing temperature up to 750 °C due to the coarse grains and better crystallinity. The leakage current property is found to vary with the type of dopant. [ABSTRACT FROM AUTHOR]