Reversible oxygen migration and phase transitions in hafnia-based ferroelectric devices

Pavan Nukala; Majid Ahmadi; Yingfen Wei; Sytze De Graaf; Evgenios Stylianidis; Tuhin Chakrabortty; Sylvia Matzen; Henny W. Zandbergen; Alexander Björling; null More Authors

doi:10.1126/science.abf3789

Reversible oxygen migration and phase transitions in hafnia-based ferroelectric devices

Pavan Nukala^*, Majid Ahmadi, Yingfen Wei, Sytze De Graaf, Evgenios Stylianidis, Tuhin Chakrabortty, Sylvia Matzen, Henny W. Zandbergen, Alexander Björling, More Authors

^*Corresponding author for this work

Research output: Contribution to journal › Article › Scientific › peer-review

103 Citations (Scopus)

Abstract

Unconventional ferroelectricity exhibited by hafnia-based thin films-robust at nanoscale sizes-presents tremendous opportunities in nanoelectronics. However, the exact nature of polarization switching remains controversial. We investigated a La0.67Sr0.33MnO3/Hf0.5Zr0.5O2 capacitor interfaced with various top electrodes while performing in situ electrical biasing using atomic-resolution microscopy with direct oxygen imaging as well as with synchrotron nanobeam diffraction. When the top electrode is oxygen reactive, we observe reversible oxygen vacancy migration with electrodes as the source and sink of oxygen and the dielectric layer acting as a fast conduit at millisecond time scales. With nonreactive top electrodes and at longer time scales (seconds), the dielectric layer also acts as an oxygen source and sink. Our results show that ferroelectricity in hafnia-based thin films is unmistakably intertwined with oxygen voltammetry.

Original language	English
Pages (from-to)	630-635
Journal	Science
Volume	372
Issue number	6542
DOIs	https://doi.org/10.1126/science.abf3789
Publication status	Published - 2021

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title = "Reversible oxygen migration and phase transitions in hafnia-based ferroelectric devices",

abstract = "Unconventional ferroelectricity exhibited by hafnia-based thin films-robust at nanoscale sizes-presents tremendous opportunities in nanoelectronics. However, the exact nature of polarization switching remains controversial. We investigated a La0.67Sr0.33MnO3/Hf0.5Zr0.5O2 capacitor interfaced with various top electrodes while performing in situ electrical biasing using atomic-resolution microscopy with direct oxygen imaging as well as with synchrotron nanobeam diffraction. When the top electrode is oxygen reactive, we observe reversible oxygen vacancy migration with electrodes as the source and sink of oxygen and the dielectric layer acting as a fast conduit at millisecond time scales. With nonreactive top electrodes and at longer time scales (seconds), the dielectric layer also acts as an oxygen source and sink. Our results show that ferroelectricity in hafnia-based thin films is unmistakably intertwined with oxygen voltammetry.",

author = "Pavan Nukala and Majid Ahmadi and Yingfen Wei and Graaf, {Sytze De} and Evgenios Stylianidis and Tuhin Chakrabortty and Sylvia Matzen and Zandbergen, {Henny W.} and Alexander Bj{\"o}rling and {More Authors}",

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T1 - Reversible oxygen migration and phase transitions in hafnia-based ferroelectric devices

AU - Nukala, Pavan

AU - Ahmadi, Majid

AU - Wei, Yingfen

AU - Graaf, Sytze De

AU - Stylianidis, Evgenios

AU - Chakrabortty, Tuhin

AU - Matzen, Sylvia

AU - Zandbergen, Henny W.

AU - Björling, Alexander

AU - More Authors, null

PY - 2021

Y1 - 2021

N2 - Unconventional ferroelectricity exhibited by hafnia-based thin films-robust at nanoscale sizes-presents tremendous opportunities in nanoelectronics. However, the exact nature of polarization switching remains controversial. We investigated a La0.67Sr0.33MnO3/Hf0.5Zr0.5O2 capacitor interfaced with various top electrodes while performing in situ electrical biasing using atomic-resolution microscopy with direct oxygen imaging as well as with synchrotron nanobeam diffraction. When the top electrode is oxygen reactive, we observe reversible oxygen vacancy migration with electrodes as the source and sink of oxygen and the dielectric layer acting as a fast conduit at millisecond time scales. With nonreactive top electrodes and at longer time scales (seconds), the dielectric layer also acts as an oxygen source and sink. Our results show that ferroelectricity in hafnia-based thin films is unmistakably intertwined with oxygen voltammetry.

AB - Unconventional ferroelectricity exhibited by hafnia-based thin films-robust at nanoscale sizes-presents tremendous opportunities in nanoelectronics. However, the exact nature of polarization switching remains controversial. We investigated a La0.67Sr0.33MnO3/Hf0.5Zr0.5O2 capacitor interfaced with various top electrodes while performing in situ electrical biasing using atomic-resolution microscopy with direct oxygen imaging as well as with synchrotron nanobeam diffraction. When the top electrode is oxygen reactive, we observe reversible oxygen vacancy migration with electrodes as the source and sink of oxygen and the dielectric layer acting as a fast conduit at millisecond time scales. With nonreactive top electrodes and at longer time scales (seconds), the dielectric layer also acts as an oxygen source and sink. Our results show that ferroelectricity in hafnia-based thin films is unmistakably intertwined with oxygen voltammetry.

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Reversible oxygen migration and phase transitions in hafnia-based ferroelectric devices

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