Direct observation of phase transition in Hf0.5Zr0.5O2 thin films affected by top electrodes using in-situ STEM heating

High-scalability HfO2-based ferroelectric thin films are promising for application in fast, energy-efficient, and high-density non-volatile memories. This ferroelectricity is believed to originate from the metastable orthorhombic phase, which is difficult to obtain. Post-metallization annealing with...

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Main Authors: Qijun Yang, Siwei Dai, Changfan Ju, Keyu Bao, Binjian Zeng, Shuaizhi Zheng, Jiajia Liao, Jiangang Guo, Sirui Zhang, Yichun Zhou, Min Liao
Format: Article
Language:English
Published: Elsevier 2025-09-01
Series:Journal of Materiomics
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Online Access:http://www.sciencedirect.com/science/article/pii/S2352847825000656
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author Qijun Yang
Siwei Dai
Changfan Ju
Keyu Bao
Binjian Zeng
Shuaizhi Zheng
Jiajia Liao
Jiangang Guo
Sirui Zhang
Yichun Zhou
Min Liao
author_facet Qijun Yang
Siwei Dai
Changfan Ju
Keyu Bao
Binjian Zeng
Shuaizhi Zheng
Jiajia Liao
Jiangang Guo
Sirui Zhang
Yichun Zhou
Min Liao
author_sort Qijun Yang
collection DOAJ
description High-scalability HfO2-based ferroelectric thin films are promising for application in fast, energy-efficient, and high-density non-volatile memories. This ferroelectricity is believed to originate from the metastable orthorhombic phase, which is difficult to obtain. Post-metallization annealing with a top electrode capping layer is a useful method for stabilizing the ferroelectric orthorhombic phase. However, direct physical evidence of the top electrode role is lacking. In this study, we visualized the dynamic process of the phase transition in Hf0.5Zr0.5O2 (HZO) thin films with TiN and Pt top electrodes during the heating and cooling processes through in-situ scanning transmission electron microscopy (STEM). The TiN top electrode stabilized the orthorhombic phase, whereas the Pt top electrode induced a phase transition to the monoclinic phase. Subsequently, we elucidated the phase transition mechanism in HZO thin films using the kinetic effect and revealed that it was related to the concentration of oxygen vacancies induced by the top electrode. This study provides valuable insights into the stabilization of the orthorhombic phase in HfO2-based ferroelectric thin films and contributes to the elucidation of the phase transition mechanism of HfO2-based ferroelectric thin films.
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institution Kabale University
issn 2352-8478
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publishDate 2025-09-01
publisher Elsevier
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spelling doaj-art-feebbe220ec744f28562f94f746cb4322025-08-20T03:24:29ZengElsevierJournal of Materiomics2352-84782025-09-0111510107510.1016/j.jmat.2025.101075Direct observation of phase transition in Hf0.5Zr0.5O2 thin films affected by top electrodes using in-situ STEM heatingQijun Yang0Siwei Dai1Changfan Ju2Keyu Bao3Binjian Zeng4Shuaizhi Zheng5Jiajia Liao6Jiangang Guo7Sirui Zhang8Yichun Zhou9Min Liao10School of Advanced Materials and Nanotechnology, Xidian University, Xi'an, 710071, ChinaSchool of Advanced Materials and Nanotechnology, Xidian University, Xi'an, 710071, ChinaKey Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, School of Materials Science and Engineering, Xiangtan University, Xiangtan, 411105, ChinaSchool of Advanced Materials and Nanotechnology, Xidian University, Xi'an, 710071, ChinaKey Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, School of Materials Science and Engineering, Xiangtan University, Xiangtan, 411105, ChinaKey Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, School of Materials Science and Engineering, Xiangtan University, Xiangtan, 411105, ChinaSchool of Advanced Materials and Nanotechnology, Xidian University, Xi'an, 710071, China; Guangzhou Institute of Technology, Xidian University, Guangzhou, 510555, ChinaBeijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, ChinaSchool of Advanced Materials and Nanotechnology, Xidian University, Xi'an, 710071, China; Corresponding author.School of Advanced Materials and Nanotechnology, Xidian University, Xi'an, 710071, ChinaSchool of Advanced Materials and Nanotechnology, Xidian University, Xi'an, 710071, China; Guangzhou Institute of Technology, Xidian University, Guangzhou, 510555, China; Corresponding author. School of Advanced Materials and Nanotechnology, Xidian University, Xi'an, 710071, China.High-scalability HfO2-based ferroelectric thin films are promising for application in fast, energy-efficient, and high-density non-volatile memories. This ferroelectricity is believed to originate from the metastable orthorhombic phase, which is difficult to obtain. Post-metallization annealing with a top electrode capping layer is a useful method for stabilizing the ferroelectric orthorhombic phase. However, direct physical evidence of the top electrode role is lacking. In this study, we visualized the dynamic process of the phase transition in Hf0.5Zr0.5O2 (HZO) thin films with TiN and Pt top electrodes during the heating and cooling processes through in-situ scanning transmission electron microscopy (STEM). The TiN top electrode stabilized the orthorhombic phase, whereas the Pt top electrode induced a phase transition to the monoclinic phase. Subsequently, we elucidated the phase transition mechanism in HZO thin films using the kinetic effect and revealed that it was related to the concentration of oxygen vacancies induced by the top electrode. This study provides valuable insights into the stabilization of the orthorhombic phase in HfO2-based ferroelectric thin films and contributes to the elucidation of the phase transition mechanism of HfO2-based ferroelectric thin films.http://www.sciencedirect.com/science/article/pii/S2352847825000656Hf0.5Zr0.5O2 ferroelectric thin filmsIn-situ STEMPhase transitionTop electrode
spellingShingle Qijun Yang
Siwei Dai
Changfan Ju
Keyu Bao
Binjian Zeng
Shuaizhi Zheng
Jiajia Liao
Jiangang Guo
Sirui Zhang
Yichun Zhou
Min Liao
Direct observation of phase transition in Hf0.5Zr0.5O2 thin films affected by top electrodes using in-situ STEM heating
Journal of Materiomics
Hf0.5Zr0.5O2 ferroelectric thin films
In-situ STEM
Phase transition
Top electrode
title Direct observation of phase transition in Hf0.5Zr0.5O2 thin films affected by top electrodes using in-situ STEM heating
title_full Direct observation of phase transition in Hf0.5Zr0.5O2 thin films affected by top electrodes using in-situ STEM heating
title_fullStr Direct observation of phase transition in Hf0.5Zr0.5O2 thin films affected by top electrodes using in-situ STEM heating
title_full_unstemmed Direct observation of phase transition in Hf0.5Zr0.5O2 thin films affected by top electrodes using in-situ STEM heating
title_short Direct observation of phase transition in Hf0.5Zr0.5O2 thin films affected by top electrodes using in-situ STEM heating
title_sort direct observation of phase transition in hf0 5zr0 5o2 thin films affected by top electrodes using in situ stem heating
topic Hf0.5Zr0.5O2 ferroelectric thin films
In-situ STEM
Phase transition
Top electrode
url http://www.sciencedirect.com/science/article/pii/S2352847825000656
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