Impact of mechanical stress on ferroelectricity in (Hf0.5Zr0.5)O2 thin films

Takahisa Shiraishi; Kiliha Katayama; Tatsuhiko Yokouchi; Takao Shimizu; Takahiro Oikawa; Osami Sakata; Hiroshi Uchida; Yasuhiko Imai; Takanori Kiguchi; Toyohiko J. Konno; Hiroshi Funakubo

doi:10.1063/1.4954942

Impact of mechanical stress on ferroelectricity in (Hf_0.5Zr_0.5)O₂ thin films

Takahisa Shiraishi, Kiliha Katayama, Tatsuhiko Yokouchi, Takao Shimizu, Takahiro Oikawa, Osami Sakata, Hiroshi Uchida, Yasuhiko Imai, Takanori Kiguchi, Toyohiko J. Konno, Hiroshi Funakubo

IMR - Institute for Materials Research (institute affiliation only)

Research output: Contribution to journal › Article › peer-review

170 Citations (Scopus)

Abstract

To investigate the impact of mechanical stress on their ferroelectric properties, polycrystalline (Hf_0.5Zr_0.5)O₂ thin films were deposited on (111)Pt-coated SiO₂, Si, and CaF₂ substrates with thermal expansion coefficients of 0.47, 4.5, and 22 × 10^-6/ °C, respectively. In-plane X-ray diffraction measurements revealed that the (Hf_0.5Zr_0.5)O₂ thin films deposited on SiO₂ 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 CaF₂ 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/cm² was observed for Pt/(Hf_0.5Zr_0.5)O₂/Pt/TiO₂/SiO₂, while ferroelectricity was barely observable for Pt/(Hf_0.5Zr_0.5)O₂/Pt/TiO₂/SiO₂/CaF₂. This result suggests that the in-plane tensile strain effectively enhanced the ferroelectricity of the (Hf_0.5Zr_0.5)O₂ thin films.

Original language	English
Article number	262904
Journal	Applied Physics Letters
Volume	108
Issue number	26
DOIs	https://doi.org/10.1063/1.4954942
Publication status	Published - 2016 Jun 27

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title = "Impact of mechanical stress on ferroelectricity in (Hf0.5Zr0.5)O2 thin films",

abstract = "To investigate the impact of mechanical stress on their ferroelectric properties, polycrystalline (Hf0.5Zr0.5)O2 thin films were deposited on (111)Pt-coated SiO2, Si, and CaF2 substrates with thermal expansion coefficients of 0.47, 4.5, and 22 × 10-6/ °C, respectively. In-plane X-ray diffraction measurements revealed that the (Hf0.5Zr0.5)O2 thin films deposited on SiO2 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 CaF2 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/cm2 was observed for Pt/(Hf0.5Zr0.5)O2/Pt/TiO2/SiO2, while ferroelectricity was barely observable for Pt/(Hf0.5Zr0.5)O2/Pt/TiO2/SiO2/CaF2. This result suggests that the in-plane tensile strain effectively enhanced the ferroelectricity of the (Hf0.5Zr0.5)O2 thin films.",

author = "Takahisa Shiraishi and Kiliha Katayama and Tatsuhiko Yokouchi and Takao Shimizu and Takahiro Oikawa and Osami Sakata and Hiroshi Uchida and Yasuhiko Imai and Takanori Kiguchi and Konno, {Toyohiko J.} and Hiroshi Funakubo",

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T1 - Impact of mechanical stress on ferroelectricity in (Hf0.5Zr0.5)O2 thin films

AU - Shiraishi, Takahisa

AU - Katayama, Kiliha

AU - Yokouchi, Tatsuhiko

AU - Shimizu, Takao

AU - Oikawa, Takahiro

AU - Sakata, Osami

AU - Uchida, Hiroshi

AU - Imai, Yasuhiko

AU - Kiguchi, Takanori

AU - Konno, Toyohiko J.

AU - Funakubo, Hiroshi

PY - 2016/6/27

Y1 - 2016/6/27

N2 - To investigate the impact of mechanical stress on their ferroelectric properties, polycrystalline (Hf0.5Zr0.5)O2 thin films were deposited on (111)Pt-coated SiO2, Si, and CaF2 substrates with thermal expansion coefficients of 0.47, 4.5, and 22 × 10-6/ °C, respectively. In-plane X-ray diffraction measurements revealed that the (Hf0.5Zr0.5)O2 thin films deposited on SiO2 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 CaF2 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/cm2 was observed for Pt/(Hf0.5Zr0.5)O2/Pt/TiO2/SiO2, while ferroelectricity was barely observable for Pt/(Hf0.5Zr0.5)O2/Pt/TiO2/SiO2/CaF2. This result suggests that the in-plane tensile strain effectively enhanced the ferroelectricity of the (Hf0.5Zr0.5)O2 thin films.

AB - To investigate the impact of mechanical stress on their ferroelectric properties, polycrystalline (Hf0.5Zr0.5)O2 thin films were deposited on (111)Pt-coated SiO2, Si, and CaF2 substrates with thermal expansion coefficients of 0.47, 4.5, and 22 × 10-6/ °C, respectively. In-plane X-ray diffraction measurements revealed that the (Hf0.5Zr0.5)O2 thin films deposited on SiO2 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 CaF2 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/cm2 was observed for Pt/(Hf0.5Zr0.5)O2/Pt/TiO2/SiO2, while ferroelectricity was barely observable for Pt/(Hf0.5Zr0.5)O2/Pt/TiO2/SiO2/CaF2. This result suggests that the in-plane tensile strain effectively enhanced the ferroelectricity of the (Hf0.5Zr0.5)O2 thin films.

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Impact of mechanical stress on ferroelectricity in (Hf_0.5Zr_0.5)O₂ thin films

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