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DF: Fachverband Dielektrische Festkörper

DF 7: Dielectric and Ferroelectric Thin Films and Nanostructures I

DF 7.6: Vortrag

Dienstag, 27. März 2007, 16:30–16:50, H11

Resistive Switching in Ferroelectric Materials — •Hermann Kohlstedt¹, Adrian Petraru¹, Kristoff Szot¹, Valanoor Nagarajan², Ulrich Poppe¹, Wolgang Speier¹, and Rainer Waser¹ — ¹Institut für Festkörperforschung (IFF) and CNI, Forschungszentrum Jülich GmbH, Jülich, Germany — ²School of Materials Science and Engineering, UNSW, NSW 2052, Sydney

We investigated the resistive switching effect in SrRuO3/PbZr0.2Ti0.8O3/Pt ferroelectric capacitors. By using a conductive atomic force microscope the piezoelectric response, the capacitance as well as the resistive current vs. the applied bias voltage was simultaneously measured. The piezoelectric response and the capacitance butterfly loop showed clear indication that the PZT films were ferroelectric. We determined a coercive field of 167 kV/cm in 30 nm thick PZT films. By increasing the bias electric field approximately a factor two larger then the coercive field we observed an electric forming process, i.e. the resistance changed strongly. Hereafter the devices showed bipolar resistive switching. The simultaneously recorded piezoelectric response data showed that after the electric forming procedure the film was ferroelectric. The difference between the coercive field and the resistive switching voltage is explained on the basis of a filament model in which the resistive switching and ferroelectricity are considered as independent phenomena. This model is supported by measurements of the resistance times area (R x A) product. Parasitic effects during the measurements of the piezo response during I-V curve cycling will be discussed.