Stability of the orthorhombic phase in (111)-oriented YO_1.5-substituted HfO₂ films

• SHIMIZU Takao

  School of Materials and Chemical Technology, Tokyo Institute of Technology

• KATAYAMA Kiliha

  Department of Innovative and Engineered Materials, Tokyo Institute of Technology

• FUNAKUBO Hiroshi

  School of Materials and Chemical Technology, Tokyo Institute of Technology Department of Innovative and Engineered Materials, Tokyo Institute of Technology Mateials Research Center for Element Strategy, Tokyo Institute of Technology

Abstract

Ferrolectric orthorhombic HfO₂-based films are potential candidates for future ferroelectirc applications. The stability of the orthorhombic phase of epitaxial YO_1.5-substituted HfO₂ films on (111) yttria-stabilized zirconia substrates was investigated for various compositions, thicknesses and underlying layers. In the case of 14 nm-thick films, only 7 mol % film consisted of a single orthrohombic phase. With decreasing amount of YO_1.5 or increasing thickness, the paraelectric monoclinic phase formed in the films. On the contrary, the highly symmetric phase was grown by the increasing amount of YO_1.5. The effect of the underlying layer was also investigated. Differences in the degree of relaxation of the buffer layer give different amounts of the monoclinic phase. These results imply the importance of the compostions as well as of the strain state to (111)-oriented epitaxial Y-substituted HfO₂ films.

Journal

• Journal of the Ceramic Society of Japan

  Journal of the Ceramic Society of Japan 126 (5), 269-275, 2018-05-01

  The Ceramic Society of Japan

Keywords

• Epitaxial film
• X-ray diffraction
• Crystal structure
• Ferroelectric
• Hafnium oxides

Details

• CRID: 1390282680264159104
• NII Article ID: 130006730897
• DOI: 10.2109/jcersj2.17247
• ISSN: 13486535
• ISSN: 18820743
• Web Site: https://www.jstage.jst.go.jp/article/jcersj2/126/5/126_17247/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed