Dielectric medium, capacitor, circuit, circuit board, device, and power storage apparatus

Abstract

The dielectric according to the present disclosure includes an oxide containing hafnium, zirconium, and gallium. In the dielectric, the molar ratio (Zr / (Hf + Zr)) of the content of zirconium to the sum of the content of hafnium and the content of zirconium is 0.2 or more and less than 1. In addition, the molar ratio Ga / (Hf + Zr + Ga) of the content of gallium to the sum of the content of hafnium, the content of zirconium, and the content of gallium is greater than 0 and less than 0.14.

Description

Technical Field

[0001] This disclosure relates to dielectrics, capacitors, circuits, circuit boards, equipment, and energy storage devices. Background Technology

[0002] Previously, it was known that the dielectric properties of HfO2 could be altered by replacing a portion of Hf with other elements. For example, Non-Patent Document 1 describes how various dopants such as Si, Zr, Al, Y, Gd, Sr, and La impart ferroelectric and antiferroelectric properties to HfO2 thin films.

[0003] Patent Document 1 describes a capacitor having a dielectric layer composed of a metal oxide containing Hf, Bi, and elements with a valence of five or higher. The elements with a valence of five or higher are selected, for example, from Nb, Ta, Mo, and W. This capacitor exhibits antiferroelectric properties.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2019 / 208340

[0007] Non-patent literature

[0008] Non-patent literature 1: Advanced Materials, (Germany), 2015, 27, 1811-1831 Summary of the Invention

[0009] This disclosure provides a dielectric material advantageous from the viewpoint of high-capacitance energy storage.

[0010] The dielectric disclosed herein comprises an oxide containing hafnium, zirconium, and gallium.

[0011] The molar ratio of zirconium content to hafnium content and the sum of zirconium content is greater than 0.2 and less than 1.

[0012] The molar ratio of gallium content to the sum of hafnium content, zirconium content, and gallium content is greater than 0 and less than 0.14.

[0013] According to this disclosure, a dielectric material that is advantageous from the viewpoint of large-capacity energy storage can be provided. Attached Figure Description

[0014] Figure 1 This is a cross-sectional view showing an example of the capacitor of this disclosure.

[0015] Figure 2This is a cross-sectional view showing another example of the capacitor of this disclosure.

[0016] Figure 3A This is a schematic diagram illustrating an example of a circuit according to the present disclosure.

[0017] Figure 3B This is a schematic diagram illustrating an example of a circuit board according to the present disclosure.

[0018] Figure 3C This is a diagram schematically illustrating an example of the device disclosed herein.

[0019] Figure 3D This is a schematic diagram illustrating an example of the energy storage device of this disclosure.

[0020] Figure 4 This is a diagram showing the X-ray diffraction (XRD) pattern of the dielectric of Example 1.

[0021] Figure 5 This is a graph showing the relationship between polarization and electric field strength in the capacitor of Example 1.

[0022] Figure 6 This is a graph showing the relationship between polarization and electric field strength in the capacitor of Example 6.

[0023] Figure 7 This is a graph showing the relationship between polarization and electric field strength in the capacitor of Comparative Example 1.

[0024] Figure 8 This is a graph showing the relationship between the molar ratio Ga / (Hf+Zr+Ga) and the molar ratio Zr / (Hf+Zr) in the dielectrics of the embodiments and comparative examples. Detailed Implementation

[0025] (The insights that form the basis of this disclosure)

[0026] When a voltage is applied to an antiferroelectric, the relative permittivity of the antiferroelectric increases with the increase of the electric field strength, and the antiferroelectric exhibits nonlinear dielectric properties. The use of antiferroelectrics in high-voltage applications is envisioned. Conversely, paraelectrics exhibit a constant relative permittivity with respect to changes in electric field strength, which is advantageous from the perspective of ease of device design.

[0027] HfO2 readily contains both antiferroelectric and ferroelectric phases. The presence of the ferroelectric phase easily leads to residual polarization. Therefore, when using HfO2 in capacitor applications, it is difficult to increase the energy storage capacity. For example, when HfO2 partially containing the ferroelectric phase is used as the dielectric layer of a capacitor, residual polarization occurs even when the external electric field is zero. This residual polarization tends to reduce the energy output during capacitor discharge.

[0028] In view of this situation, the inventors repeatedly and thoroughly investigated whether it was possible to increase the energy storage capacity in dielectrics containing hafnium oxides. Through extensive trial and error, the inventors discovered that by including oxides containing hafnium, zirconium, and gallium, and adjusting the content of these elements to a predetermined ratio, the residual polarization of the dielectric relative to the maximum polarization could be reduced. Based on this new insight, the inventors developed the dielectric of this disclosure.

[0029] (Implementation Method)

[0030] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The present disclosure is not limited to the following embodiments.

[0031] The dielectric disclosed herein comprises an oxide containing hafnium, zirconium, and gallium. In the dielectric, the molar ratio of zirconium content to the sum of hafnium and zirconium content, Zr / (Hf+Zr), is 0.2 or more and less than 1. Furthermore, the molar ratio of gallium content to the sum of hafnium, zirconium, and gallium content, Ga / (Hf+Zr+Ga), is greater than 0 and less than 0.14. With this configuration, the residual polarization of the dielectric tends to be smaller than the maximum polarization, and the dielectric readily possesses advantageous characteristics from the viewpoint of increasing energy storage capacity.

[0032] It is believed that if the contents of hafnium, zirconium and gallium in a dielectric are adjusted to the ranges mentioned above, the ferroelectric phase contained in the dielectric is more likely to decrease, and the residual polarization of the dielectric is more likely to decrease relative to the maximum polarization.

[0033] The relationship between the contents of hafnium, zirconium and gallium in the dielectric can be determined, for example, by methods such as X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDX).

[0034] In dielectrics, for example, the molar ratio of Zr / (Hf+Zr) can be 0.2 or higher and 0.8 or lower, and the molar ratio of Ga / (Hf+Zr+Ga) can be 0.06 or lower. In this case, the dielectric properties of the dielectric are close to antiferroelectric, and the relative permittivity of the dielectric can increase as the electric field strength increases. Therefore, from the viewpoint of increasing energy storage capacity, the dielectric is likely to have more advantageous properties. For example, the dielectric can be expected to be used in high-voltage applications.

[0035] In dielectrics, for example, the molar ratio of Zr / (Hf+Zr) can be greater than 0.8 and less than 1, and the molar ratio of Ga / (Hf+Zr+Ga) can be greater than 0.06 and less than 0.14. In this case, although the dielectric properties of the dielectric are close to paraelectric, the remanent polarization is small, and the maximum polarization tends to increase. Therefore, dielectrics tend to have advantageous properties from the viewpoint of increasing energy storage capacity. Furthermore, even with changes in electric field strength, the change in the relative permittivity of the dielectric tends to be small, thus simplifying the design of devices using dielectrics.

[0036] Dielectrics, for example, have Hf 1-x-y Zr x Ga y O 2±δ The composition is represented by the condition 0.2 ≤ x / (1-y) < 1 and 0 < y < 0.14. In this case, the dielectric is more likely to have advantageous properties from the viewpoint of increasing energy storage capacity.

[0037] In the above composition, δ is not limited to a specific value. δ is, for example, a value used to maintain the electrical neutrality of the dielectric. For example, when the dielectric is produced using a gas-phase method, anion deficiency is easily caused, which can easily lead to deviations relative to the stoichiometry. In the above composition, for example, the condition 0.00 ≤ δ ≤ 0.07 is satisfied.

[0038] The above composition preferably satisfies the conditions 0.2 ≤ x / (1-y) ≤ 0.8 and 0 < y ≤ 0.06. In this case, the dielectric properties of the dielectric tend to approach antiferroelectricity, and the relative permittivity of the dielectric can increase as the electric field strength increases. Therefore, from the viewpoint of increasing energy storage capacity, the dielectric tends to have more advantageous properties. For example, the dielectric can be expected to be used in high-voltage applications.

[0039] The above composition can also satisfy the conditions 0.8 < x / (1-y) < 1 and 0.06 < y < 0.14. In this case, although the dielectric properties of the dielectric tend to approach paraelectricity, the remanent polarization is small, and the maximum polarization tends to increase. Therefore, the dielectric tends to have advantageous properties from the viewpoint of increasing energy storage capacity. Furthermore, even with changes in electric field strength, the change in the relative permittivity of the dielectric tends to be small, thus simplifying the design of devices using dielectrics.

[0040] Dielectrics can be composed of a single phase or multiple phases.

[0041] The crystal structure contained in a dielectric is not limited to a specific crystal structure. For example, a dielectric may contain a fluorite structure. In this case, the dielectric is more likely to have advantageous properties from the viewpoint of increasing energy storage capacity.

[0042] The dielectric may contain, for example, at least one selected from tetragonal and orthorhombic phases. In this case, the dielectric is more likely to possess advantageous properties from the viewpoint of increasing energy storage capacity.

[0043] The method for manufacturing dielectrics is not limited to a specific method. Dielectrics can be manufactured using vacuum processes such as high-frequency (RF) magnetron sputtering, pulsed laser deposition (PLD), atomic layer deposition (ALD), and chemical vapor deposition (CVD). Dielectrics can also be manufactured using wet processes such as chemical solution deposition (CSD), sol-gel methods, and hydrothermal methods.

[0044] The form of a dielectric is not limited to a specific form. Dielectrics can be, for example, formed layers or films.

[0045] Figure 1 This is a cross-sectional view showing an example of the capacitor of this disclosure. For example... Figure 1 As shown, capacitor 1a includes a first electrode 11, a second electrode 12, and the aforementioned dielectric 20. The dielectric 20 is disposed between the first electrode 11 and the second electrode 12. Because capacitor 1a includes the dielectric 20, it can easily store a large amount of energy.

[0046] In capacitor 1a, the first electrode 11, the second electrode 12, and the dielectric 20 are not limited to a specific form. The first electrode 11, the second electrode 12, and the dielectric 20 are each, for example, formed as a layer or a film.

[0047] The thickness of the first electrode 11 is not limited to a specific value. For example, the thickness of the first electrode 11 is 50 nm or more. As a result, the internal resistance in the capacitor 1a is easily reduced. For example, the thickness of the first electrode 11 is 500 nm or less. As a result, when multiple capacitors 1a are integrated, the overall capacitance density is easily increased.

[0048] The material of the first electrode 11 is not limited to a specific material. For example, the first electrode 11 may contain at least one selected from aluminum, titanium nitride, titanium oxide, molybdenum, tungsten, tantalum, zirconium, hafnium, niobium, titanium, silicon, zinc oxide, indium oxide, and tin oxide.

[0049] The thickness of the second electrode 12 is not limited to a specific value. For example, the thickness of the second electrode 12 is 50 nm or more. As a result, the internal resistance in the capacitor 1a is easily reduced. For example, the thickness of the second electrode 12 is 500 nm or less. As a result, when multiple capacitors 1a are integrated, the overall capacitance density is easily increased.

[0050] The material of the second electrode 12 is not limited to a specific material. The second electrode 12 may include, for example, at least one selected from conductive polymers, manganese oxide, zinc oxide, indium oxide, tin oxide, titanium nitride, titanium oxide, electrolytes, and polysilicon. Examples of conductive polymers include polythiophene, polyaniline, polypyrrole, and their derivatives.

[0051] like Figure 1 As shown, capacitor 1a also includes, for example, a support body 30. First electrode 11 is disposed, for example, on support body 30. Thus, the laminate including first electrode 11, dielectric 20, and second electrode 12 is supported by support body 30, and the mechanical strength of capacitor 1a is easily increased. Support body 30 can, for example, be used as a substrate for forming first electrode 11. In capacitor 1a, support body 30 may also be omitted.

[0052] The support 30 is not limited to a specific type of support. The support 30 can be a conductor, a semiconductor, or an insulator. When the support 30 is a conductor, the support 30 and the first electrode 11 can also be integrated.

[0053] The thickness of the support 30 is not limited to a specific value. The thickness of the support 30 can be greater than 50 nm and less than 500 nm, or greater than 500 nm.

[0054] Here is an example of a method for manufacturing capacitor 1a. First, a first electrode 11 is formed on the main surface of the support 30. The formation of the first electrode 11 can be achieved, for example, by vacuum processes, plating, or coating. Examples of vacuum processes include DC sputtering, RF magnetron sputtering, pulsed laser deposition (PLD), atomic layer deposition (ALD), and chemical vapor deposition (CVD). The support 30 can be a metal foil such as aluminum foil or zirconium foil, and the support 30 and the first electrode 11 can be integrally formed.

[0055] Next, a film of dielectric 20 is formed on the first electrode 11. During the formation of the film of dielectric 20, the amorphous precursor of dielectric 20 may also be subjected to rapid thermal annealing (RTA) to promote the crystallization of dielectric 20.

[0056] Next, a second electrode 12 is formed on the dielectric 20. In forming the second electrode 12, the same vacuum process, plating, or coating can be applied as with the first electrode 11. In this way, capacitor 1a can be manufactured.

[0057] Figure 2 This is a cross-sectional view showing another example of the capacitor of this disclosure. Figure 2The capacitor 1b shown is constructed in the same manner as capacitor 1a, except where specifically described. The same reference numerals are used to denote the constituent elements of capacitor 1b that are identical or corresponding to those of capacitor 1a, and detailed descriptions are omitted. The description of capacitor 1a also applies to capacitor 1b, provided it is not technically contradictory.

[0058] like Figure 2 As shown, in capacitor 1b, at least a portion of the first electrode 11 is porous. With this configuration, the surface area of ​​the first electrode 11 can be easily increased, and the electrostatic capacitance of capacitor 1b can be easily increased. Therefore, capacitor 1b can easily store a large amount of energy. Such a porous structure can be formed, for example, by etching of metal foil and sintering of powder.

[0059] like Figure 2 As shown, for example, a film of dielectric 20 is formed on the surface of the porous portion of the first electrode 11. In this case, the method for forming the dielectric 20 can be atomic layer deposition (ALD) or chemical vapor deposition (CVD) and atomized CVD.

[0060] In capacitor 1b, the second electrode 12 includes, for example, a conductor 12a and an electrolyte 12b. For example, the electrolyte 12b is disposed between the first electrode 11 and the conductor 12a. In capacitor 1b, the electrolyte 12b is disposed, for example, to fill the voids surrounding the porous portion of the first electrode 11. The electrolyte 12b may contain at least one selected from manganese oxide, an electrolyte, and a conductive polymer. Examples of conductive polymers include polypyrrole, polythiophene, polyaniline, and derivatives thereof. The electrolyte 12b may also be a manganese compound such as manganese oxide. The electrolyte 12b may comprise a solid electrolyte.

[0061] like Figure 3A As shown, for example, a circuit 3 with capacitor 1a can be provided. Circuit 3 is not limited to a specific circuit as long as it has capacitor 1a. Circuit 3 can be an active circuit or a passive circuit. Circuit 3 can be a discharge circuit, a smoothing circuit, a decoupling circuit, or a coupling circuit. Because circuit 3 has capacitor 1a, circuit 3 easily possesses the desired characteristics. Circuit 3 can also have capacitor 1b instead of capacitor 1a.

[0062] like Figure 3B As shown, for example, a circuit board 5 can be provided that includes capacitor 1a. Since the circuit board 5 includes capacitor 1a, its design is straightforward. For example, a circuit 3 including capacitor 1a can be formed in the circuit board 5. Alternatively, the circuit board 5 can include capacitor 1b instead of capacitor 1a.

[0063] like Figure 3CAs shown, for example, a device 7 with capacitor 1a can be provided. Because device 7 has capacitor 1a, device 7 easily possesses the desired characteristics. For example, device 7 has a circuit board 5 containing capacitor 1a. Device 7 is, for example, an information terminal such as a smartphone or tablet PC. Device 7 may also have capacitor 1b instead of capacitor 1a.

[0064] like Figure 3D As shown, for example, an energy storage device 9 equipped with a capacitor 1a can be provided. Since the energy storage device 9 includes the capacitor 1a, it easily possesses the desired characteristics. Using the energy storage device 9, for example, an energy storage system 50 can be provided. The energy storage system 50 includes the energy storage device 9 and a power generation device 2. In the energy storage system 50, the electricity generated by the power generation device 2 is stored in the energy storage device 9. The power generation device 2 is, for example, a device for solar power generation or wind power generation. The energy storage device 9 is, for example, a device equipped with a lithium-ion battery or a lead-acid battery. The energy storage device 9 may also include a capacitor 1b instead of the capacitor 1a.

[0065] The applications of the aforementioned dielectric are not limited to capacitors. For example, it is possible to provide electro-optical elements, storage elements, transistors, ferroelectric data storage devices, piezoelectric elements, and thermoelectric elements, etc., that incorporate the aforementioned dielectric.

[0066] (Postscript)

[0067] Based on the above records, the following technologies are disclosed.

[0068] (Technology 1)

[0069] A dielectric comprising an oxide containing hafnium, zirconium, and gallium.

[0070] The molar ratio of zirconium content to hafnium content and the sum of zirconium content is greater than 0.2 and less than 1.

[0071] The molar ratio of gallium content to the sum of hafnium content, zirconium content, and gallium content is greater than 0 and less than 0.14.

[0072] (Technology 2)

[0073] According to the dielectric of technology 1

[0074] The molar ratio of zirconium content to hafnium content and the sum of zirconium content is greater than 0.2 and less than 0.8.

[0075] The molar ratio of gallium content to the sum of hafnium content, zirconium content, and gallium content is greater than 0 and less than 0.06.

[0076] (Technology 3)

[0077] The dielectric according to technique 1 or 2

[0078] The dielectric has Hf 1-x-y Zr x Ga y O 2±δ The composition of the representation,

[0079] The composition satisfies the conditions 0.2≤x / (1-y)<1 and 0<y<0.14.

[0080] (Technology 4)

[0081] According to the dielectric described in Technique 3

[0082] The composition further satisfies the conditions 0.2≤x / (1-y)≤0.8 and 0<y≤0.06.

[0083] (Technology 5)

[0084] The dielectric according to any one of techniques 1 to 4

[0085] The dielectric contains a fluorite structure.

[0086] (Technology 6)

[0087] The dielectric according to any one of techniques 1 to 5

[0088] The dielectric comprises at least one selected from tetragonal and orthorhombic phases.

[0089] (Technology 7)

[0090] A capacitor includes a first electrode, a second electrode, and a dielectric, wherein the dielectric is disposed between the first electrode and the second electrode.

[0091] The dielectric is any one of the dielectrics described in techniques 1 to 6.

[0092] (Technology 8)

[0093] The capacitor according to technology 7

[0094] The first electrode comprises at least one selected from aluminum, titanium nitride, titanium oxide, molybdenum, tungsten, tantalum, zirconium, hafnium, niobium, titanium, silicon, zinc oxide, indium oxide, and tin oxide.

[0095] (Technology 9)

[0096] The capacitor according to technology 7

[0097] The second electrode comprises at least one selected from conductive polymers, manganese oxide, zinc oxide, indium oxide, tin oxide, titanium nitride, titanium oxide, electrolytes, and polycrystalline silicon.

[0098] (Technology 10)

[0099] A circuit comprising a capacitor as described in any one of techniques 7 to 9.

[0100] (Technology 11)

[0101] A circuit board comprising a capacitor as described in any one of techniques 7 to 9.

[0102] (Technology 12)

[0103] An apparatus comprising a capacitor as described in any one of techniques 7 to 9.

[0104] (Technology 13)

[0105] An energy storage device comprising a capacitor as described in any one of techniques 7 to 9.

[0106] Example

[0107] The present disclosure will be further described in detail below through embodiments. Furthermore, the following embodiments are illustrative and the present disclosure is not limited to these embodiments.

[0108] (Example 1)

[0109] A polycrystalline TiN thin film with a thickness of 70 nm was formed on a single-crystal substrate with a Si (100) plane using RF magnetron sputtering to obtain the first electrode layer. Subsequently, an Hf-coated TiN film with a thickness of 15 nm was formed on the first electrode layer using ALD. 0.474 Zr 0.474 Ga 0.051 The dielectric layer is composed of O2. At this time, the dielectric in the dielectric layer is an amorphous paraelectric material. The composition of the dielectric layer is determined based on the film formation conditions of the ALD used to form the dielectric layer, with reference to the growth per cycle (GPC) when forming films of HfO2, ZrO2, and Ga2O3 in the ALD. Next, the stack comprising a single crystal substrate having a Si (100) facet, a first electrode layer, and a dielectric layer is heated at 500°C in a nitrogen atmosphere for 60 seconds to perform RTA. It is believed that through this heat treatment, the structure of the dielectric layer changes from an amorphous state to a crystal structure exhibiting an antiferroelectric tetragonal phase or an orthorhombic phase exhibiting ferroelectricity. Thus, the dielectric of Example 1 is obtained. Then, an Au thin film with a thickness of 150 nm is formed on the dielectric layer by vacuum evaporation to obtain a second electrode layer. Thus, the capacitor of Example 1 is fabricated.

[0110] The XRD measurements of the sample obtained from the dielectric of Example 1 were performed using an Aeris X-ray diffraction (XRD) apparatus manufactured by Malvern Panalytical. The results are shown below. Figure 4 . Figure 4 The vertical axis represents the diffraction intensity in arbitrary units, and the horizontal axis represents the diffraction angle 2θ. Figure 4 The expression “m” indicates the diffraction angle 2θ corresponding to monoclinic crystals, “o / t / c” indicates the diffraction angle 2θ corresponding to orthorhombic, tetragonal, or cubic crystals, and “sub.” indicates the diffraction angle corresponding to the substrate or the first electrode layer.

[0111] The polarization-electric field (PE) curves of the capacitor in Example 1 were measured using a Premier II ferroelectric testing instrument manufactured by Radiant Technologies to evaluate the dielectric properties of the dielectric in Example 1. The results are shown below. Figure 5 . Figure 5 The vertical axis represents polarization, and the horizontal axis represents electric field strength. The maximum polarization value, P, is determined from the PE curve. max And the polarization P when the electrolytic intensity becomes 0 as the electric field intensity decreases. r Find the maximum polarization P max Subtract the residual polarization P r The difference obtained (P) max -P r From the perspective of large-capacity energy storage, this large difference is advantageous. The results are shown in Table 1. Furthermore, based on the shape of the PE curve, the dielectric properties of the dielectric are evaluated to determine which of the following characteristics—antiferroelectric, paraelectric, or ferroelectric—they approximate. The results are shown in Table 1.

[0112] A: The dielectric properties of a dielectric are close to those of an antiferroelectric dielectric.

[0113] B: The dielectric properties of the dielectric are close to those of paraelectricity.

[0114] C: The dielectric properties of the dielectric are close to those of ferroelectricity.

[0115] like Figure 4 As shown, no monoclinic crystals were identified in the dielectric of Example 1. The main phase of the dielectric was confirmed to be selected from at least one of orthorhombic, tetragonal, and cubic crystals. It can be considered that the dielectric contains a fluorite structure. Figure 5 As shown, the residual polarization P r The small size suggests that the dielectric in Example 1 contains a small amount of ferroelectric phase. According to... Figure 5The shape of the PE curve shown indicates that the dielectric properties of the dielectric in Example 1 are close to antiferroelectric. In the dielectric of Example 1, the difference (P) max -P r The large amount of ferroelectric phase can be considered to indicate that there is little ferroelectric phase in the dielectric of Example 1.

[0116] (Example 2)

[0117] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Hf 0.488 Zr 0.488 Ga 0.024 O2, except as otherwise provided in Example 1, to obtain the dielectric and capacitor of Example 2. The dielectric and capacitor of Example 2 were evaluated in the same manner as in Example 1. The results are shown in Table 1. In the dielectric of Example 2, the residual polarization P r Small, poor (P) max -P r The dielectric properties of the dielectric in Example 2 are close to antiferroelectric, suggesting that there is little ferroelectric phase in the dielectric of Example 2.

[0118] (Example 3)

[0119] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Hf 0.237 Zr 0.711 Ga 0.051 O2, except as otherwise provided in Example 1, yielded the dielectric and capacitor of Example 3. The dielectric and capacitor of Example 3 were evaluated in the same manner as in Example 1. The results are shown in Table 1. In the dielectric of Example 3, the residual polarization P r Small, poor (P) max -P r The dielectric properties of the dielectric in Example 3 are close to antiferroelectric, suggesting that there is little ferroelectric phase in the dielectric of Example 3.

[0120] (Example 4)

[0121] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Hf 0.243 Zr 0.730 Ga 0.026 O2, except as otherwise provided in Example 1, yielded the dielectric and capacitor of Example 4. The dielectric and capacitor of Example 4 were evaluated in the same manner as in Example 1. The results are shown in Table 1. In the dielectric of Example 4, the residual polarization P... r Small, poor (P) max -P r The dielectric properties of the dielectric in Example 4 are close to antiferroelectric, suggesting that there is little ferroelectric phase in the dielectric of Example 4.

[0122] (Example 5)

[0123] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Hf 0.659 Zr 0.293 Ga 0.048 O2, except as otherwise provided in Example 1, yielded the dielectric and capacitor of Example 5. The dielectric and capacitor of Example 5 were evaluated in the same manner as in Example 1. The results are shown in Table 1. In the dielectric of Example 5, the residual polarization P... r Small, poor (P) max -P r (Large). In addition, the dielectric properties of the dielectric in Example 5 are close to antiferroelectric, suggesting that there is little ferroelectric phase in the dielectric of Example 5.

[0124] (Example 6)

[0125] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Hf 0.462 Zr 0.462 Ga 0.075 O2, except as otherwise provided in Example 1, yielded the dielectric and capacitor of Example 6. The dielectric and capacitor of Example 6 were evaluated in the same manner as in Example 1. The results are shown in Table 1. Figure 6 This is a graph showing the relationship between polarization and electric field strength in the capacitor of Example 6. Figure 6 The vertical axis represents polarization, and the horizontal axis represents electric field strength. In the capacitor of Example 6, the residual polarization P r The dielectric of Example 6 is considered to contain a small amount of ferroelectric phase. For example... Figure 6 As shown, in the capacitor of Example 6, the PE curve is linear, and the dielectric properties of the dielectric are close to paraelectric. On the other hand, due to the maximum polarization P... max The dielectric properties are large, therefore it is assumed that the dielectric also contains an antiferroelectric phase in a specified proportion. Although the dielectric properties of the dielectric are close to paraelectric as described above, the difference (P...) max -P r The large amount of ferroelectric phase is considered to indicate that the dielectric of Example 6 contains less ferroelectric phase.

[0126] (Example 7)

[0127] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Hf 0.451 Zr 0.451 Ga 0.098 O2, except as otherwise provided in Example 1, yielded the dielectric and capacitor of Example 7. The dielectric and capacitor of Example 7 were evaluated in the same manner as in Example 1. The results are shown in Table 1. Although the dielectric properties of the dielectric of Example 7 are close to paraelectric, the difference (P)max -P r The large amount of ferroelectric phase is considered to indicate that the dielectric of Example 7 contains less ferroelectric phase.

[0128] (Example 8)

[0129] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Hf 0.231 Zr 0.694 Ga 0.075 O2, except as otherwise provided in Example 1, yielded the dielectric and capacitor of Example 8. The dielectric and capacitor of Example 8 were evaluated in the same manner as in Example 1. The results are shown in Table 1. Although the dielectric properties of the dielectric of Example 8 are close to paraelectric, the difference (P) max -P r The dielectric of Example 8 contains a small amount of ferroelectric phase, which is considered to be large.

[0130] (Example 9)

[0131] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Hf 0.226 Zr 0.677 Ga 0.098 O2, except as otherwise provided in Example 1, yielded the dielectric and capacitor of Example 9. The dielectric and capacitor of Example 9 were evaluated in the same manner as in Example 1. The results are shown in Table 1. Although the dielectric properties of the dielectric of Example 9 are close to paraelectric, the difference (P) max -P r The large amount of ferroelectric phase in the dielectric of Example 9 is considered to indicate that the dielectric contains less ferroelectric phase.

[0132] (Comparative Example 1)

[0133] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Hf 0.500 Zr 0.500 O2, except as otherwise provided in Example 1, to obtain the dielectric and capacitor of Comparative Example 1. The dielectric and capacitor of Comparative Example 1 were evaluated in the same manner as in Example 1. The results are shown in Table 1. Figure 7 This is a graph showing the relationship between polarization and electric field strength in the capacitor of Comparative Example 1. Figure 7 The vertical axis represents polarization, and the horizontal axis represents electric field strength. For example... Figure 7 As shown, the dielectric properties of the dielectric in Comparative Example 1 are close to ferroelectric, and the remanent polarization P r Large. Therefore, in the dielectric of Comparative Example 1, the difference (P) max -P r The dielectric is small, and from the point of view, it is difficult to say that this dielectric is advantageous from the perspective of large-capacity energy storage.

[0134] (Comparative Example 2)

[0135] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Hf 0.250 Zr 0.750 O2, except as otherwise provided in Example 1, to obtain the dielectric and capacitor of Comparative Example 2. The dielectric and capacitor of Comparative Example 2 were evaluated in the same manner as in Example 1. The results are shown in Table 1. The dielectric properties of the dielectric of Comparative Example 2 are close to ferroelectric, and the remanent polarization P... r Large. Therefore, in the dielectric of Comparative Example 2, the difference (P) max -P r Small. From the perspective of large-capacity energy storage, this dielectric is hardly advantageous.

[0136] (Comparative Example 3)

[0137] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Hf 0.690 Zr 0.310 O2, except as otherwise provided in Example 1, to obtain the dielectric and capacitor of Comparative Example 3. The dielectric and capacitor of Comparative Example 3 were evaluated in the same manner as in Example 1. The results are shown in Table 1. The dielectric properties of the dielectric of Comparative Example 3 are close to paraelectric, although the remanent polarization P... r Small, but maximum polarization P max It is also small. Therefore, in the dielectric of Comparative Example 3, the difference (P) is small. max -P r Small. From the perspective of large-capacity energy storage, this dielectric is hardly advantageous.

[0138] (Comparative Example 4)

[0139] The film-forming conditions of ALD were adjusted to form a Zr- and Ga-free HfO2 thin film as the dielectric layer. Otherwise, the process was the same as in Example 1, resulting in the dielectric and capacitor of Comparative Example 4. The dielectric and capacitor of Comparative Example 4 were evaluated in the same manner as in Example 1. The results are shown in Table 1. The dielectric properties of the dielectric of Comparative Example 4 are close to paraelectric, although the remanent polarization P... r Small, but maximum polarization P max It is also small. Therefore, in the dielectric of Comparative Example 4, the difference (P) is small. max -P r Small. From the perspective of large-capacity energy storage, this dielectric is hardly advantageous.

[0140] (Comparative Example 5)

[0141] The ALD film-forming conditions were adjusted to form a ZrO2 thin film free of Hf and Ga as the dielectric layer. Otherwise, the process was the same as in Example 1, resulting in the dielectric and capacitor of Comparative Example 5. The dielectric and capacitor of Comparative Example 5 were evaluated in the same manner as in Example 1. The results are shown in Table 1. Although the dielectric properties of the dielectric of Comparative Example 5 are close to antiferroelectric, the remanent polarization P... r Large, poor (P) max -P r The dielectric is small. It is believed that the dielectric contains a considerable amount of ferroelectric phase.

[0142] (Comparative Example 6)

[0143] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Zr. 0.949 Ga 0.051 O2, except as otherwise provided in Example 1, yielded the dielectric and capacitor of Comparative Example 6. The dielectric and capacitor of Comparative Example 6 were evaluated in the same manner as in Example 1. The results are shown in Table 1. The dielectric properties of the dielectric of Comparative Example 6 are close to paraelectric, although the remanent polarization P... r Small, but maximum polarization P max It is also small. Therefore, in the dielectric of Comparative Example 6, the difference (P) is small. max -P r Small. From the perspective of large-capacity energy storage, this dielectric is hardly advantageous.

[0144] (Comparative Example 7)

[0145] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Zr. 0.902 Ga 0.098 O2, except as otherwise provided in Example 1, yielded the dielectric and capacitor of Comparative Example 7. The dielectric and capacitor of Comparative Example 7 were evaluated in the same manner as in Example 1. The results are shown in Table 1. The dielectric properties of the dielectric of Comparative Example 7 are close to paraelectric, and the remanent polarization P... r Small, but maximum polarization P max It is also small. Therefore, in the dielectric of Comparative Example 7, the difference (P) is small. max -P r Small. From the perspective of large-capacity energy storage, this dielectric is hardly advantageous.

[0146] (Comparative Example 8)

[0147] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Zr. 0.860 Ga 0.140O2, except as otherwise provided in Example 1, to obtain the dielectric and capacitor of Comparative Example 8. The dielectric and capacitor of Comparative Example 8 were evaluated in the same manner as in Example 1. The results are shown in Table 1. The dielectric properties of the dielectric of Comparative Example 8 are close to paraelectric, and the remanent polarization P... r Small, but maximum polarization P max It is also small. Therefore, in the dielectric of Comparative Example 8, the difference (P) is small. max -P r Small. From the perspective of large-capacity energy storage, this dielectric is hardly advantageous.

[0148] (Comparative Example 9)

[0149] The film formation conditions of ALD were adjusted so that the composition of the dielectric layer was Hf 0.430 Zr 0.430 Ga 0.140 O2, except as otherwise provided in Example 1, yielded the dielectric and capacitor of Comparative Example 9. The dielectric and capacitor of Comparative Example 9 were evaluated in the same manner as in Example 1. The results are shown in Table 1. The dielectric properties of the dielectric of Comparative Example 9 are close to paraelectric, and the remanent polarization P... r Small, but maximum polarization P max It is also small. Therefore, in the dielectric of Comparative Example 9, the difference (P) is small. max -P r Small. From the perspective of large-capacity energy storage, this dielectric is hardly advantageous.

[0150] As shown in Table 1, the P of the dielectrics in Examples 1-9 max -P r The large value of these dielectrics indicates that they contain few ferroelectric phases, which is advantageous from the perspective of large-capacity energy storage. Figure 8 This is a graph showing the relationship between the molar ratio Ga / (Hf+Zr+Ga) and the molar ratio Zr / (Hf+Zr) in the dielectrics of the embodiments and comparative examples. Figure 8 In the diagram, the vertical axis represents the molar ratio Ga / (Hf+Zr+Ga), and the horizontal axis represents the molar ratio Zr / (Hf+Zr). Figure 8 In the table, "〇" indicates an embodiment, and "×" indicates a comparative example. Table 1 lists... Figure 8 The symbols associated with each mark are described in the corresponding embodiments or comparative examples. For example... Figure 8 As shown by the dashed rectangle, in the dielectric of the embodiment, the molar ratio Zr / (Hf+Zr) is greater than 0.2 and less than 1, and the molar ratio Ga / (Hf+Zr+Ga) is greater than 0 and less than 0.14. This implies that if their molar ratios are within such a range, the dielectric tends to have advantageous properties from the viewpoint of large-capacity energy storage. Figure 8As shown by the rectangle with dotted lines, in the dielectrics of Examples 1-5, the molar ratio Zr / (Hf+Zr) is 0.2 or more and 0.8 or less, and the molar ratio Ga / (Hf+Zr+Ga) is greater than 0 and 0.06 or less. This suggests that if their molar ratios are within such ranges, the dielectric is more likely to have more advantageous properties from the viewpoint of large-capacity energy storage.

[0151]

[0152] Industrial availability

[0153] The dielectric disclosed herein contains a small amount of ferroelectric phase, which readily reduces remanent polarization. This dielectric is advantageous from the viewpoint of large-capacity energy storage.

Claims

1. A dielectric comprising an oxide, said oxide containing hafnium, zirconium, and gallium. The molar ratio of zirconium content to hafnium content and the sum of zirconium content is greater than 0.2 and less than 1. The molar ratio of gallium content to the sum of hafnium content, zirconium content, and gallium content is greater than 0 and less than 0.

14.

2. The dielectric according to claim 1, The molar ratio of zirconium content to hafnium content and the sum of zirconium content is greater than 0.2 and less than 0.

8. The molar ratio of gallium content to the sum of hafnium content, zirconium content, and gallium content is greater than 0 and less than 0.

06.

3. The dielectric according to claim 1, The dielectric has Hf 1-x-y Zr x Ga y O 2±δ The composition of the representation, The composition satisfies the conditions 0.2≤x / (1-y)<1 and 0<y<0.

14.

4. The dielectric according to claim 3, The composition further satisfies the conditions 0.2≤x / (1-y)≤0.8 and 0<y≤0.

06.

5. The dielectric according to claim 1, The dielectric contains a fluorite structure.

6. The dielectric according to claim 1, The dielectric comprises at least one selected from tetragonal and orthorhombic phases.

7. A capacitor comprising a first electrode, a second electrode, and a dielectric, wherein the dielectric is disposed between the first electrode and the second electrode. The dielectric is the dielectric as described in claim 1.

8. The capacitor according to claim 7, The first electrode comprises at least one selected from aluminum, titanium nitride, titanium oxide, molybdenum, tungsten, tantalum, zirconium, hafnium, niobium, titanium, silicon, zinc oxide, indium oxide, and tin oxide.

9. The capacitor according to claim 7, The second electrode comprises at least one selected from conductive polymers, manganese oxide, zinc oxide, indium oxide, tin oxide, titanium nitride, titanium oxide, electrolytes, and polycrystalline silicon.

10. A circuit comprising a capacitor as described in any one of claims 7 to 9.

11. A circuit board comprising a capacitor as described in any one of claims 7 to 9.

12. An apparatus comprising a capacitor as described in any one of claims 7 to 9.

13. An energy storage device comprising a capacitor as described in any one of claims 7 to 9.

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