Subscriber access provided by United Arab Emirates University | Libraries Deanship
Article 2
Investigation of the switching mechanism in TiObased RRAM: a two-dimensional EDX approach Daniela Carta, Iulia Salaoru, Ali Khiat, Anna Regoutz, Christoph Mitterbauer, Nicholas M. Harrison, and Themistoklis Prodromakis ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.6b04919 • Publication Date (Web): 13 Jul 2016 Downloaded from http://pubs.acs.org on July 16, 2016
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
ACS Applied Materials & Interfaces is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 20
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
ACS Applied Materials & Interfaces
Investigation of the switching mechanism in TiO2-based RRAM: a two-dimensional EDX approach
Daniela Carta,*,a Iulia Salaoru, a Ali Khiat, a Anna Regoutz, a Christoph Mitterbauer, b Nicholas M. Harrison, c Themistoklis Prodromakis a
a
Nano Group, Southampton Nanofabrication Centre, Department of Electronics and Computer
Science, University of Southampton, Southampton SO17 1BJ, United Kingdom b
FEI Company, P.O. Box 80066, 5600 KA Eindhoven, The Netherlands
c
Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ, United
Kingdom
*
Corresponding Author. E-mail:
[email protected] Keywords: resistive memory, titanium dioxide, memristors, energy dispersive X-ray spectroscopy, thin films, resistive switching 1 ACS Paragon Plus Environment
ACS Applied Materials & Interfaces
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 2 of 20
Abstract The next generation of non-volatile 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 multi-state 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 life time of TiO2-based resistive random access memory (RRAM).
2 ACS Paragon Plus Environment
Page 3 of 20
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
ACS Applied Materials & Interfaces
1.
Introduction
Nanoscale resistive random access memory (RRAM) cells are typically metal-insulator-metal (MIM) architectures where the insulator typically comprises a transition metal oxide thin-film. RRAM cells are also known as memristors and due to their simple structure can be incorporated into devices with high density that function at low power and high speed (
