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Oxygen Vacancy Dynamics in Different Switching Modes of Hf0.5Zr0.5O2−δ

Knabe, Judith ; Goss, Kalle ; Liu, Yen Po ; Golias, Evangelos LU orcid ; Zakharov, Alexei LU ; Cojocariu, Iulia ; Jugovac, Matteo ; Locatelli, Andrea ; Menteş, Tevfik O. and Céolin, Denis , et al. (2025) In ACS Nano 19(32). p.29405-29415
Abstract

HfO2, one of the most common materials in resistive switching devices, can stabilize in a ferroelectric orthorhombic phase, enabling two nonvolatile polarization states via oxygen displacement in the unit cell. Under certain conditions, ferroelectric and resistive switching can coexist, independently addressable, within one device. This study employs operando spectroscopic analysis to elucidate the role of oxygen in both switching processes. A conductive filament is identified through a local valence change at the oxide surface via X-ray Photoelectron Emission Microscopy, allowing vacancy density and filament diameter evaluation. This provides well-founded experimental evidence of a conductive filament in orthorhombic... (More)

HfO2, one of the most common materials in resistive switching devices, can stabilize in a ferroelectric orthorhombic phase, enabling two nonvolatile polarization states via oxygen displacement in the unit cell. Under certain conditions, ferroelectric and resistive switching can coexist, independently addressable, within one device. This study employs operando spectroscopic analysis to elucidate the role of oxygen in both switching processes. A conductive filament is identified through a local valence change at the oxide surface via X-ray Photoelectron Emission Microscopy, allowing vacancy density and filament diameter evaluation. This provides well-founded experimental evidence of a conductive filament in orthorhombic Hf0.5Zr0.5O2−δ(HZO) in application-relevant device geometry. Depth-dependent changes in the electronic signature of HZO and La0.8Sr0.2MnO3−δ(LSMO) with ferroelectric field cycling are identified by Hard X-ray Photoelectron Spectroscopy. Polarization-dependent shifts in the Hf core level align with the oxygen vacancy migration during ferroelectric switching. Fatigue-related vacancy generation causes an inhomogeneous reduction that does not propagate into the bottom electrode and extended domain pinning at the HZO/LSMO interface. This highlights the importance of interface engineering for the ferroelectric performance and of the oxygen affinity of the bottom electrode for both switching regimes.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
ferroelectric switching, HAXPES, HZO, resistive switching, spectroscopy, XPEEM
in
ACS Nano
volume
19
issue
32
pages
11 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:105013741447
  • pmid:40767388
ISSN
1936-0851
DOI
10.1021/acsnano.5c07038
language
English
LU publication?
yes
id
69fec3a2-594e-45c1-91db-3be59a7f82d0
date added to LUP
2025-11-05 14:37:27
date last changed
2025-11-06 03:00:03
@article{69fec3a2-594e-45c1-91db-3be59a7f82d0,
  abstract     = {{<p>HfO<sub>2</sub>, one of the most common materials in resistive switching devices, can stabilize in a ferroelectric orthorhombic phase, enabling two nonvolatile polarization states via oxygen displacement in the unit cell. Under certain conditions, ferroelectric and resistive switching can coexist, independently addressable, within one device. This study employs operando spectroscopic analysis to elucidate the role of oxygen in both switching processes. A conductive filament is identified through a local valence change at the oxide surface via X-ray Photoelectron Emission Microscopy, allowing vacancy density and filament diameter evaluation. This provides well-founded experimental evidence of a conductive filament in orthorhombic Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2−δ</sub>(HZO) in application-relevant device geometry. Depth-dependent changes in the electronic signature of HZO and La<sub>0.8</sub>Sr<sub>0.2</sub>MnO<sub>3−δ</sub>(LSMO) with ferroelectric field cycling are identified by Hard X-ray Photoelectron Spectroscopy. Polarization-dependent shifts in the Hf core level align with the oxygen vacancy migration during ferroelectric switching. Fatigue-related vacancy generation causes an inhomogeneous reduction that does not propagate into the bottom electrode and extended domain pinning at the HZO/LSMO interface. This highlights the importance of interface engineering for the ferroelectric performance and of the oxygen affinity of the bottom electrode for both switching regimes.</p>}},
  author       = {{Knabe, Judith and Goss, Kalle and Liu, Yen Po and Golias, Evangelos and Zakharov, Alexei and Cojocariu, Iulia and Jugovac, Matteo and Locatelli, Andrea and Menteş, Tevfik O. and Céolin, Denis and Gutsche, Alexander and Gogoi, Daisy and Weber, Moritz L. and Timm, Rainer and Dittmann, Regina}},
  issn         = {{1936-0851}},
  keywords     = {{ferroelectric switching; HAXPES; HZO; resistive switching; spectroscopy; XPEEM}},
  language     = {{eng}},
  number       = {{32}},
  pages        = {{29405--29415}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{ACS Nano}},
  title        = {{Oxygen Vacancy Dynamics in Different Switching Modes of Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2−δ</sub>}},
  url          = {{http://dx.doi.org/10.1021/acsnano.5c07038}},
  doi          = {{10.1021/acsnano.5c07038}},
  volume       = {{19}},
  year         = {{2025}},
}