Regensburg 2016 – scientific programme

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DS: Fachverband Dünne Schichten

DS 39: Resistive Effects I

DS 39.2: Talk

Thursday, March 10, 2016, 09:45–10:00, H8

Impact of Cation-Stoichiometry on Switching Speed and Data Retention in SrTiO₃ Thin Film Devices — •Nicolas Raab¹, Christoph Bäumer¹, Karsten Fleck², Stephan Menzel¹, and Regina Dittmann¹ — ¹Peter Grünberg Institut, Forschungszentrum Jülich GmbH, 52428 Jülich — ²Institut für Werkstoffe der Elektrotechnik (IWE-2), RWTH Aachen, 52074 Aachen

SrTiO₃ is a model material for resistive switching oxides. Among various proposed switching models, the filamentary switching based on oxygen migration is widely accepted for SrTiO₃. It is generally assumed that defects have a strong impact on the resistive switching properties of SrTiO₃. However, the correlation between different types of defects present in thin film devices and the resistively switching properties remains elusive.

We fabricated single-crystalline SrTiO₃ thin films with different cation ratio to investigate the stoichiometry-related and therefore defect-dependent influence on the resistive switching properties. Beyond a certain degree, non-stoichiometry is accommodated by the formation of extended defects rather than by point defects which are the dominant defect type in the more stoichiometric case. In the devices with either Ti- or Sr-excess a lower current in the pristine state and a higher current in the low resistance state was observed. These non-stoichiometric devices exhibit a larger memory window and a significantly better data retention. We will present a consistent explanation for this modified switching properties in non-stoichiometric thin film devices, supported by an estimation of the filament diameters.