Improved electrical properties of (Pb, La)TiO3 thin films using compositionally and structurally compatible LaNiO3 thin films as bottom electrodes

Homogeneous LaNiO3 thin films were grown on thermally oxidized silicon (SiO2/Si) substrates by a sol-gel technique, for the subsequent sol-gel deposition of (Pb, La)TiO3 thin films, under the assumption that the structural and compositional compatibility between ferroelectric films and bottom electrodes could lead to enhanced electrical properties of ferroelectric thin films. In this work, the LaNiO3 films served three functions: the first was used as bottom electrodes for the fabrication of integrated ferroelectric devices on Si due to their low resistivity; the second was used as a seeding layer, promoting perovskite phase formation due to their structural compatibility with ferroelectric films; and the third was to suppress the composition diffusion between ferroelectric films and bottom electrodes due to their composition compatibility. The experimental results demonstrated that (Pb, La)TiO3 films prepared on the LaNiO3/SiO2/Si substrates had excellent electrical properties. The dielectric constant and dielectric loss were 1468 and 0.033, respectively. The dielectric constant is rather high among the values reported for (Pb, La)TiO3 thin films. The remanent polarization and coercive field were 4.24 muC/cm(2) and 23.2 kV/cm, respectively. (C) 2001 American Institute of Physics.