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Title: Impact of mechanical stress on ferroelectricity in (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films

Abstract

To investigate the impact of mechanical stress on their ferroelectric properties, polycrystalline (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films were deposited on (111)Pt-coated SiO{sub 2}, Si, and CaF{sub 2} substrates with thermal expansion coefficients of 0.47, 4.5, and 22 × 10{sup −6}/ °C, respectively. In-plane X-ray diffraction measurements revealed that the (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films deposited on SiO{sub 2} and Si substrates were under in-plane tensile strain and that their volume fraction of monoclinic phase decreased as this strain increased. In contrast, films deposited on CaF{sub 2} substrates were under in-plane compressive strain, and their volume fraction of monoclinic phase was the largest among the three kinds of substrates. The maximum remanent polarization of 9.3 μC/cm{sup 2} was observed for Pt/(Hf{sub 0.5}Zr{sub 0.5})O{sub 2}/Pt/TiO{sub 2}/SiO{sub 2}, while ferroelectricity was barely observable for Pt/(Hf{sub 0.5}Zr{sub 0.5})O{sub 2}/Pt/TiO{sub 2}/SiO{sub 2}/CaF{sub 2}. This result suggests that the in-plane tensile strain effectively enhanced the ferroelectricity of the (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films.

Authors:
 [1];  [2]; ; ;  [1];  [3];  [1];  [4];  [5];  [6];  [7]; ;  [8];  [1];  [2];  [2]
  1. Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan)
  2. (Japan)
  3. Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan)
  4. (NIMS), Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)
  5. (JASRI), Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)
  6. Department of Materials and Life Sciences, Sophia University, Chiyoda, Tokyo 102-8554 (Japan)
  7. Japan Synchrotron Radiation Research Institute (JASRI), Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)
  8. Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)
Publication Date:
OSTI Identifier:
22590623
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 108; Journal Issue: 26; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CALCIUM FLUORIDES; DEPOSITS; FERROELECTRIC MATERIALS; MONOCLINIC LATTICES; POLARIZATION; POLYCRYSTALS; SILICON OXIDES; STRAINS; STRESSES; SUBSTRATES; THERMAL EXPANSION; THIN FILMS; TITANIUM OXIDES; X-RAY DIFFRACTION

Citation Formats

Shiraishi, Takahisa, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Katayama, Kiliha, Yokouchi, Tatsuhiko, Oikawa, Takahiro, Shimizu, Takao, Sakata, Osami, Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, Japan Synchrotron Radiation Research Institute, Uchida, Hiroshi, Imai, Yasuhiko, Kiguchi, Takanori, Konno, Toyohiko J., Funakubo, Hiroshi, E-mail: funakubo.h.aa@m.titech.ac.jp, Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502, and Department of Materials Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502. Impact of mechanical stress on ferroelectricity in (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films. United States: N. p., 2016. Web. doi:10.1063/1.4954942.
Shiraishi, Takahisa, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Katayama, Kiliha, Yokouchi, Tatsuhiko, Oikawa, Takahiro, Shimizu, Takao, Sakata, Osami, Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, Japan Synchrotron Radiation Research Institute, Uchida, Hiroshi, Imai, Yasuhiko, Kiguchi, Takanori, Konno, Toyohiko J., Funakubo, Hiroshi, E-mail: funakubo.h.aa@m.titech.ac.jp, Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502, & Department of Materials Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502. Impact of mechanical stress on ferroelectricity in (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films. United States. doi:10.1063/1.4954942.
Shiraishi, Takahisa, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Katayama, Kiliha, Yokouchi, Tatsuhiko, Oikawa, Takahiro, Shimizu, Takao, Sakata, Osami, Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, Japan Synchrotron Radiation Research Institute, Uchida, Hiroshi, Imai, Yasuhiko, Kiguchi, Takanori, Konno, Toyohiko J., Funakubo, Hiroshi, E-mail: funakubo.h.aa@m.titech.ac.jp, Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502, and Department of Materials Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502. 2016. "Impact of mechanical stress on ferroelectricity in (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films". United States. doi:10.1063/1.4954942.
@article{osti_22590623,
title = {Impact of mechanical stress on ferroelectricity in (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films},
author = {Shiraishi, Takahisa and Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 and Katayama, Kiliha and Yokouchi, Tatsuhiko and Oikawa, Takahiro and Shimizu, Takao and Sakata, Osami and Synchrotron X-ray Station at SPring-8, National Institute for Materials Science and Japan Synchrotron Radiation Research Institute and Uchida, Hiroshi and Imai, Yasuhiko and Kiguchi, Takanori and Konno, Toyohiko J. and Funakubo, Hiroshi, E-mail: funakubo.h.aa@m.titech.ac.jp and Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 and Department of Materials Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502},
abstractNote = {To investigate the impact of mechanical stress on their ferroelectric properties, polycrystalline (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films were deposited on (111)Pt-coated SiO{sub 2}, Si, and CaF{sub 2} substrates with thermal expansion coefficients of 0.47, 4.5, and 22 × 10{sup −6}/ °C, respectively. In-plane X-ray diffraction measurements revealed that the (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films deposited on SiO{sub 2} and Si substrates were under in-plane tensile strain and that their volume fraction of monoclinic phase decreased as this strain increased. In contrast, films deposited on CaF{sub 2} substrates were under in-plane compressive strain, and their volume fraction of monoclinic phase was the largest among the three kinds of substrates. The maximum remanent polarization of 9.3 μC/cm{sup 2} was observed for Pt/(Hf{sub 0.5}Zr{sub 0.5})O{sub 2}/Pt/TiO{sub 2}/SiO{sub 2}, while ferroelectricity was barely observable for Pt/(Hf{sub 0.5}Zr{sub 0.5})O{sub 2}/Pt/TiO{sub 2}/SiO{sub 2}/CaF{sub 2}. This result suggests that the in-plane tensile strain effectively enhanced the ferroelectricity of the (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films.},
doi = {10.1063/1.4954942},
journal = {Applied Physics Letters},
number = 26,
volume = 108,
place = {United States},
year = 2016,
month = 6
}
  • We have investigated the dielectric response of a series of {l_brace}100{r_brace} fiber-textured (Ba{sub x}Sr{sub 1{minus}x})Ti{sub 1+y}O{sub 3+z} samples deposited by liquid-source metalorganic chemical vapor deposition onto Pt/SiO{sub 2}/Si, as a function of the two most commonly varied microstructural parameters: film thickness and Ti nonstoichiometry {ital y}. We find that the overall behavior of these samples is adequately described by mean-field, Landau{endash}Ginzburg{endash}Devonshire theory as for bulk ferroelectrics. However, we quantify the impact of three separable factors for these films that greatly alter the dielectric susceptibility as a function of temperature, compared to that found for bulk ceramic samples at the samemore » Ba/Sr ratio of 70/30: (i) Ti nonstoichiometry; (ii) the apparent interface effect; and (iii) the plane equibiaxial stress state resulting from thermal expansion mismatch strains. When these factors are properly taken into consideration, we show that these fine grained thin films behave in a manner entirely consistent with expectations based on bulk behavior. Implications can therefore be drawn concerning the nature of size effects in this ferroelectric system. {copyright} {ital 1999 American Institute of Physics.}« less
  • We have investigated the dielectric response of a series of {l_brace}100{r_brace} fiber-textured (Ba{sub x}Sr{sub 1-x})Ti{sub 1+y}O{sub 3+z} samples deposited by liquid-source metalorganic chemical vapor deposition onto Pt/SiO{sub 2}/Si, as a function of the two most commonly varied microstructural parameters: film thickness and Ti nonstoichiometry y. We find that the overall behavior of these samples is adequately described by mean-field, Landau-Ginzburg-Devonshire theory as for bulk ferroelectrics. However, we quantify the impact of three separable factors for these films that greatly alter the dielectric susceptibility as a function of temperature, compared to that found for bulk ceramic samples at the same Ba/Srmore » ratio of 70/30: (i) Ti nonstoichiometry; (ii) the apparent interface effect; and (iii) the plane equibiaxial stress state resulting from thermal expansion mismatch strains. When these factors are properly taken into consideration, we show that these fine grained thin films behave in a manner entirely consistent with expectations based on bulk behavior. Implications can therefore be drawn concerning the nature of size effects in this ferroelectric system.« less
  • A study of the microstructure, thermal stability, nanoindentation mechanical properties, and residual stress evolution of nanolayered Mo{endash}Si{endash}N/SiC thin films as a function of vacuum annealing time and temperature is reported. Multilayers of Mo{endash}Si{endash}N (MoSi{sub 2.2}N{sub 2.5}) and SiC were deposited by magnetron sputtering from planar MoSi{sub 2} and SiC targets onto single crystal silicon wafers. The relative amount of both components was varied (12.5{endash}50 vol.thinsp{percent} of SiC) while keeping the bilayer thickness constant (12 nm), or the bilayer thickness was varied (6{endash}24 nm) with constant Mo{endash}Si{endash}N to SiC ratio (25 vol.thinsp{percent} of SiC). Mechanical properties were measured by nanoindentation onmore » as-deposited films and films annealed in vacuum at 500 and 900thinsp{degree}C. Microstructure and thermal stability were examined by cross-sectional transmission electron microscopy, glancing angle x-ray diffraction and nuclear resonance broadening. Stress evolution induced by thermal annealing was determined by measuring optically the change in curvature of coated silicon beams. In the as-deposited state, all films exhibited an amorphous microstructure. At 900thinsp{degree}C SiC still remained amorphous, but Mo{endash}Si{endash}N had developed a microstructure where nanocrystals of Mo{sub 5}Si{sub 3} were embedded in an amorphous matrix. The interface between Mo{endash}Si{endash}N and SiC was indirectly shown to be stable at least up to 41 h annealing at 1075thinsp{degree}C in vacuum. The potential of Mo{endash}Si{endash}N as a barrier layer against intermixing between nanolayered MoSi{sub 2} and SiC at 900thinsp{degree}C has been demonstrated. Hardness, modulus and residual stress followed the volume fraction rule of mixture of both constituents of the nanolayered Mo{endash}Si{endash}N/SiC structure. Consequently, by optimizing the volume fraction of the constituents, zero residual stress on a silicon substrate is possible after annealing. {copyright} {ital 1999 American Vacuum Society.}« less
  • The combined effects of mechanical stress and surface electromigration on the dynamics of transgranular voids in passivated metallic thin films are analyzed based on self-consistent dynamical simulations. Depending on the strength of the electric and stress fields, void morphological instabilities can lead to film failure by propagation from the void surface of either faceted slits or finer-scale crack-like features. Most importantly, there exists a narrow range of applied stress for given strength of electric field over which slit formation can be inhibited completely. {copyright} {ital 1998 American Institute of Physics.}
  • Nano-materials are commonly stabilized by supports to maintain their desired shape and size. When these nano-materials take up interstitial atoms, this attachment to the support induces mechanical stresses. These stresses can be high when the support is rigid. High stress in the nano-material is typically released by delamination from the support or by the generation of defects, e.g., dislocations. As high mechanical stress can be beneficial for tuning the nano-materials properties, it is of general interest to deduce how real high mechanical stress can be gained. Here, we show that below a threshold nano-material size, dislocation formation can be completelymore » suppressed and, when delamination is inhibited, even the ultrahigh stress values of the linear elastic limit can be reached. Specifically, for hydrogen solved in epitaxial niobium films on sapphire substrate supports a threshold film thickness of 6 nm was found and mechanical stress of up to (−10 ± 1) GPa was reached. This finding is of basic interest for hydrogen energy applications, as the hydride stability in metals itself is affected by mechanical stress. Thus, tuning of the mechanical stress-state in nano-materials may lead to improved storage properties of nano-sized materials.« less