Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 27: Joint Poster Session: Functionalized semiconductor nanowires (DS, jointly with HL); Resistive switching (DS, jointly with DF, KR, HL)
HL 27.8: Poster
Monday, March 11, 2013, 17:00–20:00, Poster B1
Transmission X-ray microscopy of resistively switched epitaxial Fe-doped SrTiO3 MIM structures — •Holger Wasmund1, Annemarie Köhl1, Peter Guttmann2, Katja Henzler2, Stephan Werner2, Sebastian Schmelzer1, Regina Dittmann1, and Rainer Waser1 — 1FZ Jülich, PGI-7, Germany — 2HZB, Institute for soft Matter and functional Materials, Germany
There exists strong experimental evidence that the resistance change in transition metal oxides is caused by a valency change on a nanoscale. Transmission X-ray microscopy exhibit the potential of observing bulk spectral information of the sample with a spatial resolution of 25nm unlike other methods which exclusively probe the surface e.g. XPS. One central issue in TXM probe preparation is the sample thickness which should not exceed 100nm. As a first approach we studied polycrystalline STO devices on SiN membranes which were switched in two different resistive states. To analyse epitaxial grown STO devices we prepared SRO|STO|Pt MIM structures on top of NGO substrates with an intermediate sacrifical layer by pulsed laser deposition and sputtered Pt electrodes. A chromium adhesion layer and a carbon film were deposited on top of the stack in order to serve as a carrier foil, followed by a selective etching step of the sarifical layer to release the specimen from the substrate. XAS spectra measurements at the Ti L edge and the Fe L edge for electrode pads in different resistive states were realized at the U41 beamline at Bessy II. We observed significant changes in the Ti spectra which are indications for a valency change in a filament like region.