skip to main content

SciTech ConnectSciTech Connect

Title: Growth of epitaxial orthorhombic YO{sub 1.5}-substituted HfO{sub 2} thin film

YO{sub 1.5}-substituted HfO{sub 2} thin films with various substitution amounts were grown on (100) YSZ substrates by the pulsed laser deposition method directly from the vapor phase. The epitaxial growth of film with different YO{sub 1.5} amounts was confirmed by the X-ray diffraction method. Wide-area reciprocal lattice mapping measurements were performed to clarify the crystal symmetry of films. The formed phases changed from low-symmetry monoclinic baddeleyite to high-symmetry tetragonal/cubic fluorite phases through an orthorhombic phase as the YO{sub 1.5} amount increased from 0 to 0.15. The additional annular bright-field scanning transmission electron microscopy indicates that the orthorhombic phase has polar structure. This means that the direct growth by vapor is of polar orthorhombic HfO{sub 2}-based film. Moreover, high-temperature X-ray diffraction measurements showed that the film with a YO{sub 1.5} amount of 0.07 with orthorhombic structure at room temperature only exhibited a structural phase transition to tetragonal phase above 450 °C. This temperature is much higher than the reported maximum temperature of 200 °C to obtain ferroelectricity as well as the expected temperature for real device application. The growth of epitaxial orthorhombic HfO{sub 2}-based film helps clarify the nature of ferroelectricity in HfO{sub 2}-based films (186 words/200 words)
Authors:
 [1] ;  [2] ; ; ;  [3] ;  [1] ;  [4]
  1. Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta, Midrori-ku, Yokohama 226-8503 (Japan)
  2. Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta, Midrori-ku, Yokohama 226-8502 (Japan)
  3. Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)
  4. (Japan)
Publication Date:
OSTI Identifier:
22486352
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BADDELEYITE; CRYSTALS; ENERGY BEAM DEPOSITION; EPITAXY; FLUORITE; HAFNIUM OXIDES; LASER RADIATION; MONOCLINIC LATTICES; ORTHORHOMBIC LATTICES; PHASE TRANSFORMATIONS; PULSED IRRADIATION; SUBSTRATES; SYMMETRY; TEMPERATURE RANGE 0273-0400 K; TEMPERATURE RANGE 0400-1000 K; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION; YTTRIUM OXIDES; ZIRCONIUM OXIDES