Ferroelectricity in dopant-free HfO2 thin films prepared by pulsed laser deposition

Yongjian Luo, Zhenxun Tang, Xiaozhe Yin, Chao Chen, Zhen Fan, Minghui Qin, Min Zeng, Guofu Zhou, Xingsen Gao, Xubing Lu, Jiyan Dai, Deyang Chen, Jun Ming Liu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)

Abstract

As a high-k material, hafnium oxide (HfO2) has been used in gate dielectrics for decades. Since the discovery of polar phase in Si-doped HfO2 films, chemical doping has been widely demonstrated as an effective approach to stabilize the ferroelectric phase in HfO2 based thin films. However, the extra capping layer deposition, post-growth annealing and wake-up effect are usually required to arouse the ferroelectricity in HfO2 based thin films, resulting in the increase of complexity for sample synthesis and the impediment of device application. In this study, the ferroelectricity is observed in non-capped dopant-free HfO2 thin films prepared by pulsed laser deposition (PLD) without post-growth annealing. By adjusting the deposited temperature, oxygen pressure and thickness, the maximum polarization up to 14.7 μC/cm2 was obtained in 7.4 nm-thick film. The fraction of orthorhombic phase, concentrations of defects and size effects are considered as possible mechanisms for the influences of ferroelectric properties. This study indicates that PLD is an effective technique to fabricate high-quality ferroelectric HfO2 thin films in the absence of chemical doping, capping layer deposition and post-growth annealing, which may boost the process of nonvolatile memory device application.

Original languageEnglish
Pages (from-to)311-318
Number of pages8
JournalJournal of Materiomics
Volume8
Issue number2
DOIs
Publication statusPublished - Mar 2022

Keywords

  • Ferroelectricity
  • Hafnium oxide
  • Orthorhombic phase
  • Pulsed laser deposition

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Metals and Alloys

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