title: Epitaxial Brownmillerite Oxide Thin Films for Reliable Switching Memory.
abstract: Resistive switching memory, which is mostly based on polycrystalline thin films, suffers from wide distributions in switching parameters-including set voltage, reset voltage, and resistance-in their low- and high-resistance states. One of the most commonly used methods to overcome this limitation is to introduce inhomogeneity. By contrast, in this paper, we obtained uniform resistive switching parameters and sufficiently low forming voltage by maximizing the uniformity of an epitaxial thin film. To achieve this result, we deposited an SrFeOx/SrRuO3 heteroepitaxial structure onto an SrTiO3 (001) substrate by pulsed laser deposition, and then we deposited an Au top electrode by electron-beam evaporation. This device exhibited excellent bipolar resistance switching characteristics, including a high on/off ratio, narrow distribution of key switching parameters, and long data retention time. We interpret these phenomena in terms of a local, reversible phase transformation in the SrFeOx film between brownmillerite and perovskite structures. Using the brownmillerite structure and atomically uniform thickness of the heteroepitaxial SrFeOx thin film, we overcame two major hurdles in the development of resistive random-access memory devices: high forming voltage and broad distributions of switching parameters.
authors.affiliation: Department of Physics and Oxide Research Centre, Hankuk University of Foreign Studies , Yongin 449-791, Korea.
authors.forename: Susant K
authors.initials: SK
authors.lastname: Acharya
authors.affiliation: Department of Physics and Oxide Research Centre, Hankuk University of Foreign Studies , Yongin 449-791, Korea.
authors.forename: Raveendra Venkata
authors.initials: RV
authors.lastname: Nallagatla
authors.affiliation: Department of Physics and Oxide Research Centre, Hankuk University of Foreign Studies , Yongin 449-791, Korea.
authors.forename: Octolia
authors.initials: O
authors.lastname: Togibasa
authors.affiliation: Department of Physics and Oxide Research Centre, Hankuk University of Foreign Studies , Yongin 449-791, Korea.
authors.forename: Bo W
authors.initials: BW
authors.lastname: Lee
authors.affiliation: Department of Physics and Oxide Research Centre, Hankuk University of Foreign Studies , Yongin 449-791, Korea.
authors.forename: Chunli
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Physics and Oxide Research Centre, Hankuk University of Foreign Studies , Yongin 449-791, Korea.
authors.forename: Chang U
authors.initials: CU
authors.lastname: Jung
authors.affiliation: Division of Quantum Phases and Devices, Department of Physics, Konkuk University , Seoul 143-791, Korea.
authors.forename: Bae Ho
authors.initials: BH
authors.lastname: Park
authors.affiliation: Department of Physics and Department of Energy Systems Research, Ajou University , Suwon 443-749, Korea.
authors.forename: Ji-Yong
authors.initials: JY
authors.lastname: Park
authors.affiliation: Department of Physics, Ewha Womans University , Seoul 120-750, Korea.
authors.forename: Yunae
authors.initials: Y
authors.lastname: Cho
authors.affiliation: Department of Physics, Ewha Womans University , Seoul 120-750, Korea.
authors.forename: Dong-Wook
authors.initials: DW
authors.lastname: Kim
authors.affiliation: Department of Material Science and Engineering, Seoul National University , Seoul 151-747, Korea.
authors.forename: Janghyun
authors.initials: J
authors.lastname: Jo
authors.affiliation: Department of Material Science and Engineering, Seoul National University , Seoul 151-747, Korea.
authors.forename: Deok-Hwang
authors.initials: DH
authors.lastname: Kwon
authors.affiliation: Department of Material Science and Engineering, Seoul National University , Seoul 151-747, Korea.
authors.forename: Miyoung
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Material Science and Engineering and Inter-University Semiconductor Research Center, Seoul National University , Seoul 151-744, Korea.
authors.forename: Cheol Seong
authors.initials: CS
authors.lastname: Hwang
authors.affiliation: Department of Physics Education, Seoul National University , Seoul 151-748, Korea.
authors.forename: Seung C
authors.initials: SC
authors.lastname: Chae
keywords: RRAM; SrFeOx thin film; atomically smooth surface; brownmillerite structure; uniform switching parameters