title: Investigation of the Switching Mechanism in TiO2-Based RRAM: A Two-Dimensional EDX Approach.
abstract: The next generation of nonvolatile memory storage may well be based on resistive switching in metal oxides. TiO2 as transition metal oxide has been widely used as active layer for the fabrication of a variety of multistate memory nanostructure devices. However, progress in their technological development has been inhibited by the lack of a thorough understanding of the underlying switching mechanisms. Here, we employed high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) combined with two-dimensional energy dispersive X-ray spectroscopy (2D EDX) to provide a novel, nanoscale view of the mechanisms involved. Our results suggest that the switching mechanism involves redistribution of both Ti and O ions within the active layer combined with an overall loss of oxygen that effectively render conductive filaments. Our study shows evidence of titanium movement in a 10 nm TiO2 thin-film through direct EDX mapping that provides a viable starting point for the improvement of the robustness and lifetime of TiO2-based resistive random access memory (RRAM).
authors.affiliation: Nano Group, Southampton Nanofabrication Centre, Department of Electronics and Computer Science, University of Southampton , Southampton SO17 1BJ, United Kingdom.
authors.forename: Daniela
authors.initials: D
authors.lastname: Carta
authors.affiliation: Nano Group, Southampton Nanofabrication Centre, Department of Electronics and Computer Science, University of Southampton , Southampton SO17 1BJ, United Kingdom.
authors.forename: Iulia
authors.initials: I
authors.lastname: Salaoru
authors.affiliation: Nano Group, Southampton Nanofabrication Centre, Department of Electronics and Computer Science, University of Southampton , Southampton SO17 1BJ, United Kingdom.
authors.forename: Ali
authors.initials: A
authors.lastname: Khiat
authors.affiliation: Nano Group, Southampton Nanofabrication Centre, Department of Electronics and Computer Science, University of Southampton , Southampton SO17 1BJ, United Kingdom.
authors.forename: Anna
authors.initials: A
authors.lastname: Regoutz
authors.affiliation: FEI Company , P.O. Box 80066, 5600 KA Eindhoven, The Netherlands.
authors.forename: Christoph
authors.initials: C
authors.lastname: Mitterbauer
authors.affiliation: Department of Chemistry, Imperial College London , Exhibition Road, London SW7 2AZ, United Kingdom.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Harrison
authors.affiliation: Nano Group, Southampton Nanofabrication Centre, Department of Electronics and Computer Science, University of Southampton , Southampton SO17 1BJ, United Kingdom.
authors.forename: Themistoklis
authors.initials: T
authors.lastname: Prodromakis
keywords: energy dispersive X-ray spectroscopy; memristors; resistive memory; resistive switching; thin films; titanium dioxide