Stabilizing Schottky‐to‐Ohmic Switching in HfO<sub>2</sub>‐Based Ferroelectric Films via Electrode Design
The discovery of ferroelectric phases in HfO<sub>2</sub>-based films has reignited interest in ferroelectrics and their application in resistive switching (RS) devices. This study investigates the pivotal role of electrodes in facilitating the Schottky-to-Ohmic transition (SOT) observed in devices consisting of ultrathin epitaxial ferroelectric Hf<sub>0.93</sub>Y<sub>0.07</sub>O<sub>2</sub> (YHO) films deposited on La<sub>0.67</sub>Sr<sub>0.33</sub>MnO<sub>3</sub>-buffered Nb-doped SrTiO<sub>3</sub> (NbSTO|LSMO) with Ti|Au top electrodes. These findings indicate combined filamentary RS and ferroelectric switching occurs in devices with designed electrodes, having an ON/OFF ratio of over 100 during about 10<sup>5</sup> cycles. Transport measurements of modified device stacks show no change in SOT when the ferroelectric YHO layer is replaced with an equivalent hafnia-based layer, Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> (HZO). However, incomplete SOT is observed for variations in the top electrode thickness or material, as well as LSMO electrode thickness. This underscores the importance of employing oxygen-reactive electrodes and a bottom electrode with reduced conductivity to stabilize SOT. These findings provide valuable insights for enhancing the performance of ferroelectric RS devices through integration with filamentary RS mechanism.
Authors
- Caterina Ducati (ORCID: https://orcid.org/0000-0003-3366-6442)
- Maximilian T. Becker (ORCID: https://orcid.org/0000-0002-8221-1842)
- Judith L. MacManus‐Driscoll (ORCID: https://orcid.org/0000-0003-4987-6620)
- Megan O. Hill (ORCID: https://orcid.org/0000-0002-7663-7986)
- Dibya Phuyal (ORCID: https://orcid.org/0000-0003-0351-3138)
- Simon M. Fairclough (ORCID: https://orcid.org/0000-0003-3781-8212)
- Moritz L. Müller (ORCID: https://orcid.org/0000-0003-0076-1144)
- Nives Strkalj (ORCID: https://orcid.org/0000-0001-8293-8577)
- Ji Soo Kim (ORCID: https://orcid.org/0000-0002-7801-8302)
Institutions
- University of Freiburg (DE)
- University of Cambridge (GB)
- Institute of Physics (HR)
- KTH Royal Institute of Technology (SE)
Publication Details
- Journal
- Advanced Science
- Published
- 2025-01-09
- DOI
- https://doi.org/10.1002/advs.202409566
- Citations
- 7
- Primary Topic
- Ferroelectric and Negative Capacitance Devices
- Type
- article
- Field-Weighted Citation Impact
- 5.11
Funders
- Diamond Light Source
- Henry Royce Institute
- Cambridge Display Technology
- Royal Academy of Engineering
- European Commission
- Horizon 2020 Framework Programme
- Engineering and Physical Sciences Research Council
- Department of Materials Science and Metallurgy, University of Cambridge
- Division of Electrical, Communications and Cyber Systems
- H2020 European Research Council
- HORIZON EUROPE European Research Council