Crystal structure and dielectric characterization of a (SrTiO ₃/BaTiO₃) _n multilayer film prepared by radio frequency magnetron sputtering

(SrTiO₃/BaTiO₃) _n multilayer films with Pt bottom and top electrodes have been prepared by a double target radio frequency (RF) magnetron sputtering, and their dielectric properties have been characterized as a function of temperature, frequency, bias voltage, and applied voltage. The X-ray diffraction (XRD) pattern reveals that the deposited (SrTiO₃/BaTiO₃) _n multilayer films have a designed modulation. The interfaces within the multilayer films appear smooth and dense without any microcracks, and the adhesion is very good. The dielectric constant of the (SrTiO₃/BaTiO₃) _n multilayer film increases with increasing layer number (n), and the leakage current density is less than 1 × 10^-8 A•cm^-2 for the applied voltage less than 5 V for the 450-nm-thick (SrTiO₃/BaTiO₃) _n multilayer films. The remanent polarization (P _r) and the coercive field (E _c) of the 350-nm-thick (SrTiO ₃/BaTiO₃)₄ multilayer films are 7 μC•cm^-2 and 60 kV•cm^-1, respectively, exhibiting ferroelectricity. (SrTiO₃/BaTiO₃)₄ multilayer films have a high E _c and a lower P _r, as compared with the bulk BaTiO₃ single crystal. The 450-nm-thick (SrTiO₃/BaTiO₃)₄ multilayer films have a leakage current density-voltage characteristic, which makes them suitable for application in DRAMs capacitors.