Crystal Structure and Dielectric Characterization of a (SrTiO3/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 x 10(-8) A center dot 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 (SrTiO3/BaTiO3)(4) multilayer films are 7 mu C center dot cm(-2) and 60 kV center dot 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.