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Title: Formation of the Conducting Filament in TaOx-Resistive Switching Devices by Thermal-Gradient-Induced Cation Accumulation

Abstract

Here, the distribution of tantalum and oxygen ions in electroformed and/or switched TaOx-based resistive switching devices has been assessed by high-angle annular dark-field microscopy, X-ray energy-dispersive spectroscopy, and electron energy-loss spectroscopy. The experiments have been performed in the plan-view geometry on the cross-bar devices producing elemental distribution maps in the direction perpendicular to the electric field. The maps revealed an accumulation of +20% Ta in the inner part of the filament with a 3.5% Ta-depleted ring around it. The diameter of the entire structure was approximately 100 nm. The distribution of oxygen was uniform with changes, if any, below the detection limit of 5%. We interpret the elemental segregation as due to diffusion driven by the temperature gradient, which in turn is induced by the spontaneous current constriction associated with the negative differential resistance-type I–V characteristics of the as-fabricated metal/oxide/metal structures. A finite-element model was used to evaluate the distribution of temperature in the devices and correlated with the elemental maps. In addition, a fine-scale (~5 nm) intensity contrast was observed within the filament and interpreted as due phase separation of the functional oxide in the two-phase composition region. Understanding the temperature-gradient-induced phenomena is central to the engineering of oxidemore » memory cells.« less

Authors:
ORCiD logo [1];  [1];  [2]; ORCiD logo [3]; ORCiD logo [3]; ORCiD logo [3];  [1];  [4]; ORCiD logo [1]
  1. Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Materials Science and Engineering
  2. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Electrical and Computer Engineering
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division; Semiconductor Research Corp. (SRC), Durham, NC (United States). Microelectronics Advanced Research Corp. (MARCO); Defense Advanced Research Projects Agency (DARPA); National Science Foundation (NSF)
OSTI Identifier:
1460170
Grant/Contract Number:  
AC05-00OR22725; 1409068; MCF-677785
Resource Type:
Accepted Manuscript
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 10; Journal Issue: 27; Journal ID: ISSN 1944-8244
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 47 OTHER INSTRUMENTATION; filament; modeling; resistive switching; Soret effect; TEM; XEDS

Citation Formats

Ma, Yuanzhi, Li, Dasheng, Herzing, Andrew A., Cullen, David A., Sneed, Brian T., More, Karren L., Nuhfer, N. T., Bain, James A., and Skowronski, Marek. Formation of the Conducting Filament in TaOx-Resistive Switching Devices by Thermal-Gradient-Induced Cation Accumulation. United States: N. p., 2018. Web. doi:10.1021/acsami.8b03726.
Ma, Yuanzhi, Li, Dasheng, Herzing, Andrew A., Cullen, David A., Sneed, Brian T., More, Karren L., Nuhfer, N. T., Bain, James A., & Skowronski, Marek. Formation of the Conducting Filament in TaOx-Resistive Switching Devices by Thermal-Gradient-Induced Cation Accumulation. United States. doi:10.1021/acsami.8b03726.
Ma, Yuanzhi, Li, Dasheng, Herzing, Andrew A., Cullen, David A., Sneed, Brian T., More, Karren L., Nuhfer, N. T., Bain, James A., and Skowronski, Marek. Mon . "Formation of the Conducting Filament in TaOx-Resistive Switching Devices by Thermal-Gradient-Induced Cation Accumulation". United States. doi:10.1021/acsami.8b03726. https://www.osti.gov/servlets/purl/1460170.
@article{osti_1460170,
title = {Formation of the Conducting Filament in TaOx-Resistive Switching Devices by Thermal-Gradient-Induced Cation Accumulation},
author = {Ma, Yuanzhi and Li, Dasheng and Herzing, Andrew A. and Cullen, David A. and Sneed, Brian T. and More, Karren L. and Nuhfer, N. T. and Bain, James A. and Skowronski, Marek},
abstractNote = {Here, the distribution of tantalum and oxygen ions in electroformed and/or switched TaOx-based resistive switching devices has been assessed by high-angle annular dark-field microscopy, X-ray energy-dispersive spectroscopy, and electron energy-loss spectroscopy. The experiments have been performed in the plan-view geometry on the cross-bar devices producing elemental distribution maps in the direction perpendicular to the electric field. The maps revealed an accumulation of +20% Ta in the inner part of the filament with a 3.5% Ta-depleted ring around it. The diameter of the entire structure was approximately 100 nm. The distribution of oxygen was uniform with changes, if any, below the detection limit of 5%. We interpret the elemental segregation as due to diffusion driven by the temperature gradient, which in turn is induced by the spontaneous current constriction associated with the negative differential resistance-type I–V characteristics of the as-fabricated metal/oxide/metal structures. A finite-element model was used to evaluate the distribution of temperature in the devices and correlated with the elemental maps. In addition, a fine-scale (~5 nm) intensity contrast was observed within the filament and interpreted as due phase separation of the functional oxide in the two-phase composition region. Understanding the temperature-gradient-induced phenomena is central to the engineering of oxide memory cells.},
doi = {10.1021/acsami.8b03726},
journal = {ACS Applied Materials and Interfaces},
number = 27,
volume = 10,
place = {United States},
year = {2018},
month = {6}
}

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Cited by: 3 works
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Figures / Tables:

Figure 1. Figure 1.: (a) Low magnification plan-view high-angle annular dark-field (HAADF) image of the active area of the TaOx device. (b) High magnification HAADF image of the filament region. (c) Rotationally averaged HAADF line profile normalized by the number of pixels. The red dotted line indicates a smoothed profile.

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Works referencing / citing this record:

Stable Metallic Enrichment in Conductive Filaments in TaO x ‐Based Resistive Switches Arising from Competing Diffusive Fluxes
journal, April 2019

  • Ma, Yuanzhi; Goodwill, Jonathan M.; Li, Dasheng
  • Advanced Electronic Materials, Vol. 5, Issue 7
  • DOI: 10.1002/aelm.201800954

Spontaneous current constriction in threshold switching devices
journal, April 2019


Metallic filamentary conduction in valence change-based resistive switching devices: the case of TaO x thin film with x ∼ 1
journal, January 2019

  • Rosário, Carlos M. M.; Thöner, Bo; Schönhals, Alexander
  • Nanoscale, Vol. 11, Issue 36
  • DOI: 10.1039/c9nr05285b

Intrinsic current overshoot during thermal-runaway threshold switching events in TaO x devices
journal, July 2019

  • Goodwill, Jonathan M.; Skowronski, Marek
  • Journal of Applied Physics, Vol. 126, Issue 3
  • DOI: 10.1063/1.5087560

Nanoscale density variations in sputtered amorphous TaO x functional layers in resistive switching devices
journal, February 2020

  • Xu, Qiyun; Ma, Yuanzhi; Skowronski, Marek
  • Journal of Applied Physics, Vol. 127, Issue 5
  • DOI: 10.1063/1.5134098

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