Structure and properties of heteroepitaxial Pb(Zr0.35Ti0.65)O-3/SrRuO3 multilayer thin films on SrTiO3(100) prepared by MOCVD and RF sputtering

Epitaxial SrRuO3 thin films were deposited on SrTiO3(100) substrates by RF sputtering for use as bottom electrodes and epitaxial buffer layers. On these conductive substrates epitaxial Pb(Zr0.35Ti0.65)O-3 (PZT) thin films were deposited by metalorganic chemical vapor deposition (MOCVD). X-ray diffraction (XRD), transmission electron microscopy (TEM) and optical waveguiding were used to characterize the phase, refractive index, and film thickness of the deposited films. The epitaxial PZT films were c-axis oriented and contained similar to 19.7% volume fraction of 90 degrees domains. Ferroelectric hysteresis and dielectric measurements of epitaxial PZT ferroelectric capacitor structures formed using sputtered ITO top electrodes showed: a remanent polarization of 51.8 mu C/cm(2), a coercive field of 54.9 kV/cm, a dielectric constant of 410, a bipolar resistivity of similar to 5.8x10(9) Omega-cm at a field of 275 kV/cm, and a breakdown strength of >400 kV/cm. The cyclic fatigue behavior of the films showed a strong dependence on the choice of electrode materials and the fatiguing wave form. These data support the model that the fatigue mechanism in these films arises from the trapping of injected charge carriers and is predominately an electronic phenomenon.