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 (SiO 2/Si) substrates by a sol-gel technique, for the subsequent sol-gel deposit ion of (Pb, La)TiO3 thin films, under the assumption that the structural an d compositional compatibility between ferroelectric films and bottom electr odes could lead to enhanced electrical properties of ferroelectric thin fil ms. In this work, the LaNiO3 films served three functions: the first was us ed as bottom electrodes for the fabrication of integrated ferroelectric dev ices on Si due to their low resistivity; the second was used as a seeding l ayer, promoting perovskite phase formation due to their structural compatib ility with ferroelectric films; and the third was to suppress the compositi on 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 elec trical properties. The dielectric constant and dielectric loss were 1468 an d 0.033, respectively. The dielectric constant is rather high among the val ues reported for (Pb, La)TiO3 thin films. The remanent polarization and coe rcive field were 4.24 muC/cm(2) and 23.2 kV/cm, respectively. (C) 2001 Amer ican Institute of Physics.