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DS: Fachverband Dünne Schichten

DS 25: Focus Session: Resistive Switching by Redox and Phase Change Phenomena II (Valence and phase change in oxides)

DS 25.3: Talk

Wednesday, April 2, 2014, 12:00–12:15, CHE 89

Correlation of Local Conductivity and Imaging X-ray Photoelectron Spectroscopy in Resistively Switching SrTiO Thin Films — •Christoph Baeumer¹, Annemarie Koehl¹, Marco Moors¹, Marten Patt¹, Vitaliy Feyer¹, Carsten Wiemann¹, Claus Michael Schneider¹, Rainer Waser^1,2, and Regina Dittmann¹ — ¹Peter Grünberg Institut, Forschungszentrum Juelich GmbH, Germany — ²Institut für Werkstoffe der Elektrotechnik (IWE-2), RWTH Aachen, Germany

Resistively switching oxides are investigated extensively as a possible route towards future non-volatile memory or as basis for the design of novel neuromorphic circuits. Despite the existing strong experimental evidence that resistive switching in transition metal oxides is caused by nanoscale redox reactions, many fundamental details are not yet understood. In particular, the electronic and chemical structure of the resistively switching regions after electroforming and after each switching event remains elusive.

Here we will present a direct correlation of localized chemical composition alterations in SrTiO₃ thin films with local conductivity measurements. Imaging X-ray photoelectron spectroscopy after in-situ top electrode delamination revealed sub-micrometer regions characterized by an altered cation stoichiometry and increased surface potential, which form after electrical treatments. UHV-LC-AFM measurements showed that these regions possess strongly increased electrical conductivity. This observation hints at a non-negligible contribution of cation diffusion in the formation of conducting channels.