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Phase Controlling in HfO<sub>2</sub> Bulk Single Crystal

ORAL

Abstract

Contingent upon the miniaturization of semiconductor circuits, high-dielectric hafnium oxide (HfO2) serves an alternative to silicon oxide. Surprisingly, the continued scaling comes with unexpected ferroelectricity at nanoscale HfO2 in both pure and doped forms. These unusual findings are attributed to polymorphic nature including monoclinic, tetragonal, and orthorhombic phases and phase transitions in thin films, which is a big challenge in bulk crystal growth. Here, we show that utilizing the state-of-the-art laser floating zone technique allows the stabilization of the metastable phases at room temperature and pressure. We investigate the evolution of structural phases with various thermal treatments and doping. A comprehensive study on the structural transition pathway using in-situ transmission electron microscope (TEM) will be discussed. Our results provide insights for an alternative route for phase controlling of HfO2 and the comparisons with thin films.

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Presenters

  • Xianghan Xu

    Department of Physics and Astronomy, Rutgers University, Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA

Authors

  • Xianghan Xu

    Department of Physics and Astronomy, Rutgers University, Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA

  • Fei-Ting Huang

    Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA, Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA

  • Sang-Wook Cheong

    Rutgers University, R-CEM & Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA, Rutgers Center for Emergent Materials, Rutgers University, Department of Physics and Astronomy, Center for Emergent Materials, Rutgers University; Max Planck POSTECH/Korea Research Initiative, Pohang University of Science and Technol, Physics and Astronomy, Rutgers University, Rutgers University, Physics and Astronomy, and Laboratory for Pohang Emergent Materials and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science, Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA, Rutgers University, Piscataway, Department of Physics and Astronomy, Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Department of Physics, Rutgers University, Physics & Astronomy, Rutgers University, Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Rutgers University, New Brunswick, Physics, Rutgers University, Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA