Dielectric properties and microstructure of SrTiO3/BaTiO3 multilayer thin films prepared by a chemical route

Multilayer thin films with perovskite structures were produced by the polym eric precursor method. SrTiO3/BaTiO3 (STO/BTO) multilayers were deposited o n Pt(111)/Ti/SiO2/Si(100) substrates by the spin-coating technique and heat ed in air at 700 degreesC. The microstructure and crystalline phase of the multilayered thin films were examined by field-emission scanning electron m icroscopy (FE-SEM), transmission electron microscopy (TEM), resolution-high transmission electron microscopy (HRTEM), atomic force microscopy (AFM) an d X-ray diffraction. The SrTiO3/BaTiO3 multilayer thin films consisted of g rainy structures with an approximate grain size of 60 nm. The multilayered thin films showed a very clear interface between the components. The SrTiO3 /BaTiO3 multilayer thin films revealed dielectric constants of approximatel y 527 and loss tangents of 0.03 at 100 kHz. The dielectric constant calcula ted for this multilayer film system is the value of the sum of each individ ual component of the film, i.e. the total value of the sum of each SrTiO3 ( STO) and BaTiO3 (BTO) layer. The multilayer SrTiO3/BaTiO3 obtained by the p olymeric precursor method, also showed a ferroelectric behavior with a rema nent polarization of 2.5 muC/cm(2) and a coercive field of 30 kV/cm. The mu ltilayer films displayed good fatigue characteristics under bipolar stressi ng after application of 10(10) switching cycles. (C) 2001 Published by Else vier Science B.V. All rights reserved.