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The demonstration of significant ferroelectricity in epitaxial Y-doped HfO 2 film

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ABSTRACT

Ferroelectricity and Curie temperature are demonstrated for epitaxial Y-doped HfO2 film grown on (110) yttrium oxide-stabilized zirconium oxide (YSZ) single crystal using Sn-doped In2O3 (ITO) as bottom electrodes. The XRD measurements for epitaxial film enabled us to investigate its detailed crystal structure including orientations of the film. The ferroelectricity was confirmed by electric displacement filed – electric filed hysteresis measurement, which revealed saturated polarization of 16 μC/cm2. Estimated spontaneous polarization based on the obtained saturation polarization and the crystal structure analysis was 45 μC/cm2. This value is the first experimental estimations of the spontaneous polarization and is in good agreement with the theoretical value from first principle calculation. Curie temperature was also estimated to be about 450 °C. This study strongly suggests that the HfO2-based materials are promising for various ferroelectric applications because of their comparable ferroelectric properties including polarization and Curie temperature to conventional ferroelectric materials together with the reported excellent scalability in thickness and compatibility with practical manufacturing processes.

No MeSH data available.


Relationship between the Curie temperature (TC) and spontaneous polarization (Psat) for conventional ferroelectric materials and the present YHO-7 film. The materials include BaTiO3 4748, PbTiO3 53, PbZr1−xTixO3 5054, SrBi2Ta2O9 49, Pb2Bi4Ti5O18 55, Ba2Bi4Ti5O18 55, BaBi4Ti4O15 55, Sr2Bi4Ti4O15 56, Bi4Ti3O12 5758, Bi4−xLaxTi3O12 5960, and Bi4−xNdxTi3O12 4361.
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f5: Relationship between the Curie temperature (TC) and spontaneous polarization (Psat) for conventional ferroelectric materials and the present YHO-7 film. The materials include BaTiO3 4748, PbTiO3 53, PbZr1−xTixO3 5054, SrBi2Ta2O9 49, Pb2Bi4Ti5O18 55, Ba2Bi4Ti5O18 55, BaBi4Ti4O15 55, Sr2Bi4Ti4O15 56, Bi4Ti3O12 5758, Bi4−xLaxTi3O12 5960, and Bi4−xNdxTi3O12 4361.

Mentions: It is meaningful to compare the ferroelectric properties of HfO2 with those of other ferroelectric materials. Figure 5 shows an estimatedPs of 45 μC/cm2 and the TC of 450 °C from the present study for the YHO-7 film together with those of well-known materials such as BaTiO3 (Ps = 27 μC/cm2, TC = 130 °C)4748, SrBi2Ta2O9 (Ps = 22 μC/cm2, TC = 355 °C)49, and PZT (Ps = ~60 μC/cm2, TC = ~420 °C; Zr/(Zr + Ti) = 0.4, which is a composition for practical use)50. As summarized in Fig. 5, HfO2-based materials have the potential to perform as well as other ferroelectric materials. It should be emphasized the HfO2-based ferroelectric film has unique feature including the CMOS compatibility and robustness against the miniaturization and hydrogen atmosphere that cannot be obtained by using the other perovskite related materials1751. Figure 5 reveals that HfO2-based ferroelectric film gives these features as well as the comparable ferroelectric properties. Thus, HfO2-based materials are promising candidates for various applications—including ferroelectric random-access memory and future memory technologies such as ferroelectric tunnel junctions and piezoelectric transistors—because of their desirable characteristics such as their high compatibility to silicon-based technology and their ferroelectricity, even in ultra-thin films.


The demonstration of significant ferroelectricity in epitaxial Y-doped HfO 2 film
Relationship between the Curie temperature (TC) and spontaneous polarization (Psat) for conventional ferroelectric materials and the present YHO-7 film. The materials include BaTiO3 4748, PbTiO3 53, PbZr1−xTixO3 5054, SrBi2Ta2O9 49, Pb2Bi4Ti5O18 55, Ba2Bi4Ti5O18 55, BaBi4Ti4O15 55, Sr2Bi4Ti4O15 56, Bi4Ti3O12 5758, Bi4−xLaxTi3O12 5960, and Bi4−xNdxTi3O12 4361.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5016896&req=5

f5: Relationship between the Curie temperature (TC) and spontaneous polarization (Psat) for conventional ferroelectric materials and the present YHO-7 film. The materials include BaTiO3 4748, PbTiO3 53, PbZr1−xTixO3 5054, SrBi2Ta2O9 49, Pb2Bi4Ti5O18 55, Ba2Bi4Ti5O18 55, BaBi4Ti4O15 55, Sr2Bi4Ti4O15 56, Bi4Ti3O12 5758, Bi4−xLaxTi3O12 5960, and Bi4−xNdxTi3O12 4361.
Mentions: It is meaningful to compare the ferroelectric properties of HfO2 with those of other ferroelectric materials. Figure 5 shows an estimatedPs of 45 μC/cm2 and the TC of 450 °C from the present study for the YHO-7 film together with those of well-known materials such as BaTiO3 (Ps = 27 μC/cm2, TC = 130 °C)4748, SrBi2Ta2O9 (Ps = 22 μC/cm2, TC = 355 °C)49, and PZT (Ps = ~60 μC/cm2, TC = ~420 °C; Zr/(Zr + Ti) = 0.4, which is a composition for practical use)50. As summarized in Fig. 5, HfO2-based materials have the potential to perform as well as other ferroelectric materials. It should be emphasized the HfO2-based ferroelectric film has unique feature including the CMOS compatibility and robustness against the miniaturization and hydrogen atmosphere that cannot be obtained by using the other perovskite related materials1751. Figure 5 reveals that HfO2-based ferroelectric film gives these features as well as the comparable ferroelectric properties. Thus, HfO2-based materials are promising candidates for various applications—including ferroelectric random-access memory and future memory technologies such as ferroelectric tunnel junctions and piezoelectric transistors—because of their desirable characteristics such as their high compatibility to silicon-based technology and their ferroelectricity, even in ultra-thin films.

View Article: PubMed Central - PubMed

ABSTRACT

Ferroelectricity and Curie temperature are demonstrated for epitaxial Y-doped HfO2 film grown on (110) yttrium oxide-stabilized zirconium oxide (YSZ) single crystal using Sn-doped In2O3 (ITO) as bottom electrodes. The XRD measurements for epitaxial film enabled us to investigate its detailed crystal structure including orientations of the film. The ferroelectricity was confirmed by electric displacement filed – electric filed hysteresis measurement, which revealed saturated polarization of 16 μC/cm2. Estimated spontaneous polarization based on the obtained saturation polarization and the crystal structure analysis was 45 μC/cm2. This value is the first experimental estimations of the spontaneous polarization and is in good agreement with the theoretical value from first principle calculation. Curie temperature was also estimated to be about 450 °C. This study strongly suggests that the HfO2-based materials are promising for various ferroelectric applications because of their comparable ferroelectric properties including polarization and Curie temperature to conventional ferroelectric materials together with the reported excellent scalability in thickness and compatibility with practical manufacturing processes.

No MeSH data available.