Dresden 2009 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 15: Thin Film Metrology for Electronics, Photonics, and Photovoltaics II

DS 15.3: Vortrag

Dienstag, 24. März 2009, 16:00–16:15, GER 38

Polarization dependent interface properties of ferroelectric Schottky barriers studied by soft X-ray — •Hermann Kohlstedt¹, Adrian Petraru¹, Matthias Meiner¹, Jonathan Denlinger², Jinghua Guo², Wanli Yang², Andreas Scholl², Byron Freelon Freelon², Theo Schneller³, Rainer Waser³, Pu Yu⁴, and Ramamoorthy Ramesh⁴ — ¹Institut für Festkörperforschung, Forschungszentrum Juelich, D-52425 Juelich, Germany — ²Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley California 94720, USA — ³Institute of Materials for Electronic Engineering 2, RWTH-Aachen, Sommerfeldstr. 24, D-52074 Aachen, Germany — ⁴Department of Materials Science and Engineering and Department of Physics, University of California, Berkeley, California 94720 USA

We applied soft X-ray absorption spectroscopy to study the Ti L-edge in Pt/PbZr_0.3Ti_0.7O₃/Pt ferroelectric capacitors using a modified total electron yield method. The inner photo currents and the X-ray absorption spectra were polarization state dependent. The results are explained on the basis of photo electric effects and the inner potential in the ferroelectric capacitors as a result of back-to-back Schottky barriers superimposed by the potential due to the depolarization field. In general, the presented method offers the opportunity to investigate the electronic structure of buried metal-insulator and metal-semiconductor interfaces in thin film devices by applying simultaneously soft X-rays and an electric dc field.