Mapping current paths and temperature in thin film NbO<sub>2</sub> selector devices

ORAL

Abstract

A metal-to-insulator transition (MIT) occurs in NbO2 at high temperature coincident with a subtle change in its crystal structure. Because a similar transition occurs when sufficient electrical current is driven directly through the material, NbO2 is being considered for use as a selector in crossbar memory arrays. Theoretical studies presently disagree as to whether the bias-induced transition is simply the MIT triggered by Joule heating, or a distinct transition triggered by electric field effects. Using novel scanning transmission electron microscopy (STEM) techniques based on electron beam induced current (EBIC) imaging, we map current paths, potential, and temperature in functioning, thin-film NbO2 devices. We observe the bias-induced switching process at various stages, including the high-resistance state, the intermediate negative differential resistance regime, and the low-resistance state both with and without thermal runaway.

*This work was supported by NSF award DMR-1611036, by NSF STC award DMR-1548924, and by FAME, an SRC center sponsored by MARCO and DARPA.

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Presenters

  • B. Regan

    • Physics, University of California, Los Angeles
    • Physics , University of California, Los Angeles
    • University of California, Los Angeles

Authors

  • B. Regan

    • Physics, University of California, Los Angeles
    • Physics , University of California, Los Angeles
    • University of California, Los Angeles

  • Toyanath Joshi

    • Department of Physics, University of California-Santa Cruz
    • Physics and Astronomy, West Virginia University
    • University of California, Santa Cruz

  • Matthew Mecklenburg

    • CEMMA, Univ of Southern California
    • Univ of Southern California
    • University of Southern California
    • Center for Electron Microscopy and Microanalysis, University of Southern California

  • Brian Zutter

    • Physics , University of California, Los Angeles
    • University of California, Los Angeles

  • Gurleen Bal

    • Physics, University of California, Los Angeles
    • University of California, Los Angeles

  • Jared Lodico

    • University of California, Los Angeles
    • Physics, University of California, Los Angeles

  • David Lederman

    • Department of Physics, University of California-Santa Cruz
    • Physics, UC, Santa Cruz
    • University of California, Santa Cruz
    • Physics, University of California Santa Cruz

  • William Hubbard

    • Department of Physics & Astronomy, UCLA
    • Physics, University of California, Los Angeles
    • University of California, Los Angeles