title: Sub-10 nm Ta Channel Responsible for Superior Performance of a HfO2 Memristor.
abstract: Memristive devices are promising candidates for the next generation non-volatile memory and neuromorphic computing. It has been widely accepted that the motion of oxygen anions leads to the resistance changes for valence-change-memory (VCM) type of materials. Only very recently it was speculated that metal cations could also play an important role, but no direct physical characterizations have been reported yet. Here we report a Ta/HfO2/Pt memristor with fast switching speed, record high endurance (120 billion cycles) and reliable retention. We programmed the device to 24 discrete resistance levels, and also demonstrated over a million (2(20)) epochs of potentiation and depression, suggesting that our devices can be used for both multi-level non-volatile memory and neuromorphic computing applications. More importantly, we directly observed a sub-10 nm Ta-rich and O-deficient conduction channel within the HfO2 layer that is responsible for the switching. This work deepens our understanding of the resistance switching mechanism behind oxide-based memristive devices and paves the way for further device performance optimization for a broad spectrum of applications.
authors.affiliation: Nanodevices and Integrated Systems Laboratory, Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Nanodevices and Integrated Systems Laboratory, Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, MA 01003, USA.|Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: Lili
authors.initials: L
authors.lastname: Han
authors.affiliation: Nanodevices and Integrated Systems Laboratory, Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Peng
authors.initials: P
authors.lastname: Lin
authors.affiliation: Nanodevices and Integrated Systems Laboratory, Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, MA 01003, USA.|Ionic and Electronic Device and Materials Laboratory, Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Zhongrui
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Nanodevices and Integrated Systems Laboratory, Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, MA 01003, USA.|Ionic and Electronic Device and Materials Laboratory, Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Moon Hyung
authors.initials: MH
authors.lastname: Jang
authors.affiliation: Air Force Research Laboratory, Information Directorate, Rome, NY 13441, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Air Force Research Laboratory, Information Directorate, Rome, NY 13441, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Barnell
authors.affiliation: Ionic and Electronic Device and Materials Laboratory, Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: J Joshua
authors.initials: JJ
authors.lastname: Yang
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: Huolin L
authors.initials: HL
authors.lastname: Xin
authors.affiliation: Nanodevices and Integrated Systems Laboratory, Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Qiangfei
authors.initials: Q
authors.lastname: Xia