Engineering Ferroelectric Hf0.5Zr0.5O2 Thin Films by Epitaxial Stress

Abstract

The critical impact of epitaxial stress on the stabilization of the ferroelectric orthorhombic phase of hafnia is proved. Epitaxial bilayers of Hf0.5Zr0.5O2 and La0.67Sr0.33MnO3 electrodes were grown on a set of single crystalline oxide 001-oriented, cubic or pseudocubic setting, substrates with lattice parameter in the 3.71 - 4.21 A range. The lattice strain of the La0.67Sr0.33MnO3 electrode, determined by the lattice mismatch with the substrate, is critical in the stabilization of the orthorhombic phase of Hf0.5Zr0.5O2. On La0.67Sr0.33MnO3 electrodes tensile strained most of the Hf0.5Zr0.5O2 film is orthorhombic, whereas the monoclinic phase is favored when La0.67Sr0.33MnO3 is relaxed or compressively strained. Therefore, the Hf0.5Zr0.5O2 films on TbScO3 and GdScO3 substrates present substantially enhanced ferroelectric polarization in comparison to films on other substrates, including the commonly used SrTiO3. The capability of having epitaxial doped HfO2 films with controlled phase and polarization is of major interest for a better understanding of the ferroelectric properties and paves the way for fabrication of ferroelectric devices based on nanometric HfO2 films.

References in corpus (6)

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Cited by in corpus (26)

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• Domain Matching Epitaxy of Ferroelectric Hf0.5Zr0.5O2(111) on La2/3Sr1/3MnO3(001)
• Stabilization of competing ferroelectric phases of HfO${}_2$ under epitaxial strain
• Epitaxial Ferroelectric La-doped Hf0.5Zr0.5O2 Thin Films
• Effects of Strain and Film Thickness on the Stability of the Rhombohedral Phase of HfO2
• Guidelines for the stabilization of a polar rhombohedral phase in epitaxial Hf0.5Zr0.5O2 thin films
• Polarization and resistive switching in epitaxial 2 nm Hf${}_{0.5}$Zr${}_{0.5}$O${}_2$ tunnel junctions
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• Progress in Computational Understanding of Ferroelectric Mechanisms in HfO${}_2$
• Trilinear coupling driven ferroelectricity in HfO${}_2$
• Critical Effect of Bottom Electrode on Ferroelectricity of Epitaxial Hf0.5Zr0.5O2 Thin Films
• Fatigue and retention in the growth window of ferroelectric Hf0.5Zr0.5O2 thin films
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• Epitaxial ferroelectric hafnia stabilized by symmetry constraints
• Recent Advances in Unconventional Ferroelectrics and Multiferroics
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• Anharmonic thermodynamics redefines metastability and parent phases in ferroelectric HfO2
• Sizes of Ferroelectricity Appearance and Disappearence in Nanosized Hafnia-Zirconia:Landau-type Theory