Capacitor, dielectric for capacitor, electric circuit, circuit board, and device

Abstract

The present disclosure provides a capacitor which is advantageous in terms of the electrostatic capacitance and the dielectric breakdown electric field. A capacitor (1a) according to the present disclosure is provided with a first electrode (11), a second electrode (12) and a dielectric body (20). The dielectric body (20) is disposed between the first electrode (11) and the second electrode (12). The dielectric body (20) contains a predetermined composite oxide. The composite oxide is composed of at least one element that is selected from the group consisting of K, Rb and Cs, at least one element that is selected from the group consisting of Si, Ge and Sn, and at least one element that is selected from the group consisting of Mo and W.

Description

[Technical field]

[0001] The present disclosure relates to capacitors, dielectrics for capacitors, electric circuits, circuit boards, and devices. [Background technology]

[0002] Dielectrics containing composite oxides are known.

[0003] For example, Patent Document 1 describes an integrated circuit including a non-ferroelectric high-k insulator. The insulator includes a thin film of a metal oxide. As the metal oxide, a pyrochlore-type oxide having the general formula A2B2O7 is described. A represents an A-site atom selected from the group of metals consisting of Ba, Bi, Sr, Pb, Ca, K, Na, and La. B represents a B-site atom selected from the group of metals consisting of Ti, Zr, Ta, Hf, Mo, W, and Nb.

[0004] Non-Patent Document 1 describes the improvement of BaTa2O6 thin films for application to gate insulators in thin film transistors (TFTs). This document describes the variation of the dielectric constant of BaTa2O6 thin films with respect to oxygen partial pressure.

[0005] Non-Patent Document 2 describes the measurement results of the dielectric constant of a BaNb2O6 thin film. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2003-502837 [Non-patent literature]

[0007] [Non-Patent Document 1] Son Bui Tien et al. “Improvement of BaTa2O6 Thin Films for TFT Gate Insulator Applications”, The 66th JSAP Spring Meeting, 2019, [URL:https: / / www.researchgate.net / publication / 332216973_Improvement_of_BaTa2O6_Thin_Films_for_TFT_Gate_Insulator_Applications] [Non-Patent Document 2] DW KIM et al. “Cryatallographic orientation dependence of the dielectric constant in polymorphic BaNb2O6 thin films deposited laser ablation”, Phys. A 79, 677-680 (2004) [DOI:10.1007 / s00339-003-2232-3] Summary of the Invention [Problem to be solved by the invention]

[0008] The technology described in the above document has room for reexamination from the viewpoints of the capacitance and dielectric breakdown field of a capacitor while using a dielectric material containing a complex oxide.

[0009] Therefore, the present disclosure provides a capacitor that uses a dielectric material containing a complex oxide and is advantageous in terms of capacitance and dielectric breakdown field. [Means for solving the problem]

[0010] The capacitor of the present disclosure comprises: A first electrode; A second electrode; a dielectric material disposed between the first electrode and the second electrode and including a complex oxide; The composite oxide is At least one selected from the group consisting of K, Rb, and Cs; At least one selected from the group consisting of Si, Ge, and Sn; and at least one selected from the group consisting of Mo and W. Effect of the Invention

[0011] According to the present disclosure, it is possible to provide a capacitor that is advantageous in terms of capacitance and dielectric breakdown field while using a dielectric material containing a complex oxide. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view showing an example of a capacitor according to the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view showing another example of a capacitor according to the present disclosure. [Diagram 3] FIG. 3 is a cross-sectional view showing yet another example of a capacitor according to the present disclosure. [Figure 4] FIG. 4 is a cross-sectional view showing yet another example of a capacitor according to the present disclosure. [Diagram 5] FIG. 5 is a diagram illustrating a schematic example of an electric circuit according to the present disclosure. [Figure 6] FIG. 6 is a diagram illustrating an example of a circuit board according to the present disclosure. [Figure 7] FIG. 7 is a schematic diagram illustrating an example of the device of the present disclosure. [Figure 8] FIG. 8 is a graph showing an X-ray diffraction (XRD) pattern of the composite oxide according to the reference example. [Figure 9] FIG. 9 is a diagram showing the stable structure of CeTi0.5W1.5O6. [Figure 10A] FIG. 10A shows the stable structure of CeSi0.5W1.5O6. [Figure 10B] FIG. 10B is a diagram showing the stable structure of CeGe0.5W1.5O6. [Figure 10C] FIG. 10C is a diagram showing the stable structure of CeSn0.5W1.5O6. [Figure 10D] FIG. 10D shows the stable structure of KSi0.5W1.5O6. [Figure 10E] FIG. 10E is a diagram showing the stable structure of KGe0.5W1.5O6. [Figure 10F] FIG. 10F shows the stable structure of KSn0.5W1.5O6. [Figure 10G] FIG. 10G shows the stable structure of RbSi0.5W1.5O6. [Figure 10H] FIG. 10H shows the stable structure of RbGe0.5W1.5O6. [Figure 10I] FIG. 10I shows the stable structure of RbSn0.5W1.5O6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] (Findings on which this disclosure is based) Conventionally, in a capacitor having a dielectric material containing a complex oxide, a combination of elements contained in the complex oxide has been studied. For example, according to Patent Document 1, the A-site atom in a pyrochlore-type oxide having the general formula A2B2O7 is selected from the group of metals consisting of Ba, Bi, Sr, Pb, Ca, K, Na, and La. In addition, the B-site atom in the pyrochlore-type oxide is selected from the group of metals consisting of Ti, Zr, Ta, Hf, Mo, W, and Nb. Patent Document 1 lists the following as pyrochlore-type oxides: (Ba x Sr 1-x )2(Ta y Nb 1-y )2O7, which satisfies the conditions 0≦x≦1.0 and 0≦y≦1.0. The metal oxide material described in Patent Document 1 has a relatively high dielectric constant and is used in integrated circuits.

[0014] On the other hand, in terms of the characteristics of a capacitor, it is important that the dielectric constant of the dielectric is high from the viewpoint of the capacitance of the capacitor, and the dielectric breakdown field, which is the upper limit of the electric field that can be applied to the dielectric, is also important.

[0015] Therefore, the present inventors have conducted extensive research to develop a capacitor that is advantageous in terms of high capacitance and high dielectric breakdown field. As a result, they have newly discovered that by using a dielectric material containing a complex oxide made of a combination of elements not described in the above documents, the capacitance of the capacitor is likely to be high and the dielectric breakdown field is likely to be high. Based on this new knowledge, the present inventors have devised the capacitor according to the present disclosure.

[0016] (Embodiments of the present disclosure) Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0017] FIG. 1 is a cross-sectional view showing an example of a capacitor of the present disclosure. As shown in FIG. 1, the capacitor 1a includes a first electrode 11, a second electrode 12, and a dielectric 20. The dielectric 20 is disposed between the first electrode 11 and the second electrode 12. The dielectric 20 includes a predetermined complex oxide. The complex oxide includes at least one selected from the group consisting of K, Rb, and Cs, at least one selected from the group consisting of Si, Ge, and Sn, and at least one selected from the group consisting of Mo and W. When the dielectric 20 includes such a complex oxide, the dielectric 20 is likely to have a high relative dielectric constant, and the capacitor 1a is likely to have a high electrostatic capacitance. In addition, the dielectric breakdown field of the dielectric 20 is likely to be high. Therefore, the energy density of the capacitor 1a is likely to be increased. The complex oxide may include a trace amount of impurities. The trace amount of impurities may be composed of elemental species other than the above-mentioned elemental species. For example, the trace amount of impurities may be 5 mass% or less with respect to 100 mass parts of the complex oxide.

[0018] The above composite oxide is composed of, for example, any one of K, Rb, and Cs. This makes it easier for the dielectric 20 to have a high relative dielectric constant and a high dielectric breakdown electric field. The composite oxide may contain two or more selected from the group consisting of K, Rb, and Cs. In this case, the ratio of the number of atoms of the element that is contained most abundantly among K, Rb, and Cs based on the atomic number standard to the total number of atoms of K, Rb, and Cs is, for example, 70% or more. The ratio may be 80% or more, 90% or more, 95% or more, or 99% or more.

[0019] The composite oxide may contain either one of Cs and K. In this case, the dielectric 20 is more likely to have a high relative dielectric constant and a high dielectric breakdown electric field.

[0020] The composite oxide is composed of, for example, any one of Si, Ge, and Sn. This makes it easier for the dielectric 20 to have a high relative dielectric constant and a high dielectric breakdown electric field. The composite oxide may contain two or more selected from the group consisting of Si, Ge, and Sn. In this case, the ratio of the number of atoms of the element that is contained most abundantly among Si, Ge, and Sn based on the atomic number standard to the total number of atoms of Si, Ge, and Sn is, for example, 70% or more. The ratio may be 80% or more, 90% or more, 95% or more, or 99% or more.

[0021] The composite oxide is composed of, for example, any one of Mo and W. This makes it easier for the dielectric 20 to have a high relative dielectric constant and a high dielectric breakdown electric field. The composite oxide may contain both Mo and W. In this case, the ratio of the number of atoms of the element Mo and W that is contained in a larger amount based on the atomic number standard to the total number of atoms of Mo and W is, for example, 70% or more. The ratio may be 80% or more, 90% or more, 95% or more, or 99% or more.

[0022] The composite oxide may contain any one of K, Rb, and Cs, any one of Si, Ge, and Sn, and any one of Mo and W. This makes it easier for the dielectric 20 to have a high relative dielectric constant and a high dielectric breakdown electric field.

[0023] The composition of the above composite oxide is not limited to a specific composition. The composite oxide may be, for example, α B β C γ O δ In this composition, A is at least one selected from the group consisting of K, Rb, and Cs. B is at least one selected from the group consisting of Si, Ge, and Sn. C is at least one selected from the group consisting of Mo and W. This composition satisfies the conditions of 0.9≦α≦1.1, 0.25≦β≦1, 1≦γ≦2, and 5.5≦δ≦6.5. When the composite oxide has such a composition, the dielectric 20 is more likely to have a high relative dielectric constant and a high dielectric breakdown electric field.

[0024] The composition may satisfy the condition α=1. The composition may satisfy the condition 0.3≦β≦0.9, 0.3≦β≦0.8, 0.3≦β≦0.7, 0.3≦β≦0.6, 0.4≦β≦0.6, or β=0.5. The composition may satisfy the condition γ=1.5. The composition may satisfy the condition δ=6.

[0025] The crystal structure of the complex oxide is not limited to a specific crystal structure. The complex oxide has, for example, a pyrochlore type crystal structure. This makes it easier for the dielectric 20 to have a high relative dielectric constant and a high dielectric breakdown field.

[0026] The entire dielectric 20 may be composed of the composite oxide, or a part of the dielectric 20 may be composed of the composite oxide. In the dielectric 20, the composite oxide may form a continuous phase or a dispersed phase.

[0027] The relative dielectric constant of the dielectric 20 is not limited to a specific value. The relative dielectric constant of the dielectric 20 may be 55 or more, 60 or more, 70 or more, 80 or more, or 100 or more. The relative dielectric constant of the dielectric 20 is 10,000 or less. In other words, the relative dielectric constant of the dielectric 20 is, for example, 55 or more and 10,000 or less.

[0028] The dielectric breakdown field of the dielectric 20 is not limited to a specific value. The dielectric breakdown field of the dielectric 20 at -273°C is, for example, 10 V / nm or more, may be 13 V / nm or more, or may be 16 V / nm or more. The dielectric breakdown field of the dielectric 20 at -273°C is, for example, 20 V / nm or less. In other words, the dielectric breakdown field of the dielectric 20 at -273°C is 10 V / nm or more and 20 V / nm or less.

[0029] The following document explains Energy above hull, which is the energy difference from the thermodynamic convex hull, as an index for evaluating the stability and reactivity of a compound. The closer the Energy above hull is to 0, the higher the stability of the compound. For example, if the Energy above hull is 0.1 eV / atom or less, it is understood that the compound has a high possibility of existing and is relatively stable (see Figure 4). For example, the Energy above hull calculated based on first-principles calculations for a compound having the following composition is shown in Table 1.

[0030] Tsuneki Muraoka and Akira Miura, "Development, Evaluation Methods and Applications of Ceramics for Electronics, Chapter 9, Section 1, Thermodynamic Stability and Reactivity of Materials Using Computational Chemistry and Informatics," Technical Information Association, 2020 (URL: https: / / eprints.lib.hokudai.ac.jp / dspace / bitstream / 2115 / 79152 / 3 / Final_20200804%EF%BC%BFHUSCUP_4.pdf)

[0031] [Table 1]

[0032] It is understood from Table 1 that the above composite oxides can exist stably.

[0033] The method for producing the composite oxide is not limited to a specific method. The composite oxide may be produced with reference to the method described in the following document. For example, a stoichiometric mixture of at least one nitrate selected from the group consisting of K, Rb, and Cs, at least one oxide selected from the group consisting of Si, Ge, and Sn, and at least one oxide selected from the group consisting of Mo and W is prepared. This mixture is sintered in air at a predetermined temperature for a predetermined time to obtain a powder. The obtained powder is treated by a ball mill in a solvent such as cyclohexane. The powder is then pressed into a pallet and fired in air at a predetermined temperature for a predetermined time. This allows the production of a composite oxide.

[0034] Gordon J. et al. “Diffuse scattering in the cesium pyrochlore CsTi 0.5 W 1.5 O6”, Materials Research Bulletin, Volume 43, Issue 4, 1 April 2008, Pages 787-795, [DOI:https: / / doi.org / 10.1016 / j.materresbull.2007.12.017] The crystal structure of the complex oxide can be determined, for example, by performing Rietveld refinement on the diffraction data obtained by powder X-ray diffraction measurement or powder neutron diffraction measurement. Powder neutron diffraction measurement is performed, for example, using a high-resolution powder diffractometer at The High Flux Australian Reactor (HIFAR) of the Australian Nuclear Science and Technology Organisation (ANSTO). After the complex oxide sample is placed in a thin-walled vanadium can, measurements are performed in an angular range of 10°≦2θ≦150° in steps of 0.05° using neutrons having a wavelength of 1.337 Å. Powder X-ray diffraction measurement is performed, for example, using a Debye-Scherrer diffractometer. After the complex oxide sample is placed in a thin-walled quartz capillary, measurements are performed in an angular range of 5°≦2θ≦85° in steps of 0.01° using X-rays having a wavelength of 0.80088 Å.

[0035] As shown in FIG. 1, the dielectric 20 in the capacitor 1a is, for example, a film. The method of disposing the dielectric 20 in the capacitor 1a is not limited to a specific method. The dielectric 20 may be formed by, for example, spin coating, inkjet, die coating, roll coating, bar coating, Langmuir-Blodgett, dip coating, or spray coating. This makes it easier for the dielectric 20 to have a high relative dielectric constant and a high dielectric breakdown field. The dielectric 20 may be formed by sputtering, anodization, vacuum evaporation, pulsed laser deposition (PLD), atomic layer deposition (ALD), or chemical vapor deposition (CVD).

[0036] 1, the dielectric 20 is disposed, for example, between the first electrode 11 and the second electrode 12 in the thickness direction of the dielectric 20. The second electrode 12 covers, for example, at least a portion of the dielectric 20.

[0037] The materials forming the first electrode 11 and the second electrode 12 are not limited to a specific material. Each of the first electrode 11 and the second electrode 12 includes, for example, a metal. The first electrode 11 includes, for example, a valve metal. Examples of the valve metal are Al, Ta, Nb, and Bi. The first electrode 11 includes, for example, at least one valve metal selected from the group consisting of Al, Ta, Nb, and Bi. The first electrode 11 may include a precious metal such as gold or platinum, may include Ni, or may include a metal element of group 13, group 14, or group 15.

[0038] The second electrode 12 may contain, for example, a valve metal such as Al, Ta, Nb, or Bi, a precious metal such as gold, silver, or platinum, Ni, or a metal element of Group 13, Group 14, or Group 15. The second electrode 12 contains, for example, at least one selected from the group consisting of Al, Ta, Nb, Bi, gold, silver, platinum, and Ni.

[0039] 1, the first electrode 11 has a principal surface 11p. One principal surface of the dielectric 20 is in contact with the principal surface 11p, for example. The second electrode 12 has a principal surface 12p parallel to the principal surface 11p, for example. The other principal surface of the dielectric 20 is in contact with the principal surface 12p, for example.

[0040] Fig. 2 is a cross-sectional view showing another example of a capacitor of the present disclosure. Capacitor 1b shown in Fig. 2 is configured similarly to capacitor 1a, except for parts that will be particularly described. Components of capacitor 1b that are the same as or correspond to those of capacitor 1a are given the same reference numerals, and detailed description will be omitted. The description of capacitor 1a also applies to capacitor 1b as long as there is no technical contradiction. The same also applies to capacitors 1c and 1d described below.

[0041] As shown in Fig. 2, the capacitor 1b is an electrolytic capacitor. In the capacitor 1b, at least a part of the first electrode 11 is porous. With such a configuration, the surface area of ​​the first electrode 11 is likely to be large, and the capacitor 1b is likely to have a high capacitance. Such a porous structure can be formed by, for example, a method such as etching a metal foil or sintering a powder.

[0042] 2, for example, a film of a dielectric 20 is disposed on the surface of the porous portion of the first electrode 11. The method of forming the dielectric 20 can be, for example, spin coating, inkjet, die coating, roll coating, bar coating, Langmuir-Blodgett, dip coating, or spray coating. The dielectric 20 may be formed by, for example, sputtering, anodization, vacuum deposition, PLD, ALD, or CVD.

[0043] The first electrode 11 includes a valve metal such as Al, Ta, Nb, Zr, Hf, and Bi. The second electrode 12 may include, for example, a solidified silver-containing paste, a carbon material such as graphite, or both a solidified silver-containing paste and a carbon material such as graphite.

[0044] In capacitor 1b, electrolyte 13 is disposed between first electrode 11 and second electrode 12. In detail, electrolyte 13 is disposed between dielectric 20 and second electrode 12. In capacitor 1b, for example, second electrode 12 and electrolyte 13 form a cathode. In capacitor 1b, electrolyte 13 is disposed so as to fill voids around a porous portion of first electrode 11, for example.

[0045] The electrolyte 13 includes, for example, at least one selected from the group consisting of an electrolytic solution and a conductive polymer. Examples of the conductive polymer include polypyrrole, polythiophene, polyaniline, and derivatives thereof. The electrolyte 13 may be a manganese compound such as manganese oxide. The electrolyte 13 may include a solid electrolyte.

[0046] The electrolyte 13 containing a conductive polymer can be formed by performing chemical polymerization, electrolytic polymerization, or both chemical polymerization and electrolytic polymerization of a raw material monomer on the dielectric 20. The electrolyte 13 containing a conductive polymer may also be formed by depositing a solution or dispersion of the conductive polymer on the dielectric 20.

[0047] Fig. 3 is a cross-sectional view showing yet another example of a capacitor according to the present disclosure. In the capacitor 1c shown in Fig. 3, at least a part of the first electrode 11 is porous. With such a configuration, the surface area of ​​the first electrode 11 is likely to be large, and the capacitor 1c is likely to have a high capacitance. Such a porous structure can be formed by, for example, a method such as etching a metal foil and sintering a powder.

[0048] 3, for example, a film of the dielectric 20 is disposed on the upper part of the porous part of the first electrode 11. For example, spin coating, inkjet, die coating, roll coating, bar coating, Langmuir-Blodgett, dip coating, or spray coating can be used as a method for forming the dielectric 20. In the capacitor 1c, the dielectric 20 is disposed so as to fill the voids around the porous part of the first electrode 11, for example.

[0049] FIG. 4 is a cross-sectional view showing yet another example of the capacitor of the present disclosure. In the capacitor 1d shown in FIG. 4, the dielectric 20 is, for example, a film. In this film, a different dielectric 22 different from the dielectric 20 is dispersed and arranged. As a method for forming this film, spin coating, inkjet, die coating, roll coating, bar coating, Langmuir-Blodgett, dip coating, or spray coating can be adopted. For example, a film containing the dielectric 20 and the different dielectric 22 is obtained by forming a coating of a precursor liquid containing the raw material of the dielectric 20 and particles of the different dielectric 22 by the above-mentioned method. This film may be formed by sputtering, anodization, vacuum deposition, PLD, ALD, or CVD.

[0050] The heterogeneous dielectric 22 is not limited to a specific dielectric as long as it is a dielectric of a different type from the dielectric 20. The heterogeneous dielectric 22 has, for example, a higher dielectric constant than that of the dielectric 20. The heterogeneous dielectric 22 may be, for example, a perovskite compound such as BaTiO3, PbTiO3, and SrTiO3, or may be a layered perovskite compound. The heterogeneous dielectric 22 may include at least one selected from the group consisting of a Ruddlesden-Popper compound, a Dion-Jacobson compound, a tungsten bronze compound, and a pyrochlore compound.

[0051] The size of the particles of the different dielectric material 22 is not limited to a specific value. The particles of the different dielectric material 22 have a size of, for example, 1 nm or more and 100 nm or less.

[0052] FIG. 5 is a diagram showing a schematic example of an electric circuit according to the present disclosure. The electric circuit 3 includes a capacitor 1a. The electric circuit 3 may be an active circuit or a passive circuit. The electric circuit 3 may be a discharge circuit, a smoothing circuit, a decoupling circuit, or a coupling circuit. Since the electric circuit 3 includes the capacitor 1a, the electric circuit 3 is likely to exhibit a desired performance. For example, the noise in the electric circuit 3 is likely to be reduced by the capacitor 1a. The electric circuit 3 may include a capacitor 1b, 1c, or 1d instead of the capacitor 1a.

[0053] Fig. 6 is a diagram illustrating an example of a circuit board according to the present disclosure. As illustrated in Fig. 6, the circuit board 5 includes a capacitor 1a. For example, an electric circuit 3 including the capacitor 1a is formed on the circuit board 5. The circuit board 5 may be an embedded board or a motherboard. The circuit board 5 may include a capacitor 1b, 1c, or 1d instead of the capacitor 1a.

[0054] FIG. 7 is a diagram showing a schematic diagram of an example of the device of the present disclosure. As shown in FIG. 7, the device 7 includes, for example, a capacitor 1a. The device 7 includes, for example, a circuit board 5 including the capacitor 1a. Since the device 7 includes the capacitor 1a, the device 7 is likely to exhibit a desired performance. The device 7 may be an electronic device, a communication device, a signal processing device, or a power supply device. The device 7 may be a server, an AC adapter, an accelerator, or a flat panel display such as a liquid crystal display (LCD). The device 7 may be a USB charger, a solid state drive (SSD), an information terminal such as a PC, a smartphone, or a tablet PC, or an Ethernet switch.

[0055] (Additional Note) From the above description, the following techniques are disclosed.

[0056] (Technology 1) A first electrode; A second electrode; a dielectric material disposed between the first electrode and the second electrode and including a complex oxide; The composite oxide is At least one selected from the group consisting of K, Rb, and Cs; At least one selected from the group consisting of Si, Ge, and Sn; At least one selected from the group consisting of Mo and W; Capacitor.

[0057] (Technology 2) The composite oxide is Consisting of one of K, Rb, and Cs; The capacitor according to technique 1.

[0058] (Technology 3) The composite oxide is composed of any one of Cs and K. The capacitor according to technique 1.

[0059] (Technology 4) The composite oxide is Consisting of any one of Si, Ge, and Sn; A capacitor according to any one of claims 1 to 3.

[0060] (Technology 5) The composite oxide is Consisting of either Mo or W; A capacitor according to any one of the first to fourth aspects.

[0061] (Technology 6) The composite oxide is A α B β C γ O δ The composition is represented by In the composition, A is at least one selected from the group consisting of K, Rb, and Cs; B is at least one selected from the group consisting of Si, Ge, and Sn; C is at least one selected from the group consisting of Mo and W; The composition satisfies the conditions of 0.9≦α≦1.1, 0.25≦β≦1, 1≦γ≦2, and 5.5≦δ≦6.5. A capacitor according to any one of claims 1 to 5.

[0062] (Technology 7) The composite oxide has a pyrochlore type crystal structure. A capacitor according to any one of the first to sixth aspects.

[0063] (Technology 8) Contains a complex oxide, The composite oxide is At least one selected from the group consisting of K, Rb, and Cs; At least one selected from the group consisting of Si, Ge, and Sn; At least one selected from the group consisting of Mo and W; Dielectric for capacitors.

[0064] (Technology 9) An electric circuit comprising the capacitor according to any one of claims 1 to 7.

[0065] (Technology 10) A circuit board comprising the capacitor according to any one of claims 1 to 7.

[0066] (Technology 11) A device comprising the capacitor according to any one of claims 1 to 7. EXAMPLES

[0067] The present disclosure will be described in detail below with reference to examples. Note that the following examples are merely illustrative and the present disclosure is not limited to the following examples.

[0068] (Calculation of relative dielectric constant) From the database The Materials Project (https: / / materialsproject.org / ), RbTi 0.5 W 1.5 The structure of a crystal (mp-1219784) with the composition O6 was obtained. 0.5 W 1.5The initial structure of the target complex oxide with a given composition was determined by replacing elements in the O6 structure. Structural optimization calculations were performed on the determined initial structure using density functional theory (DFT), a first-principles calculation method. This calculation was performed using the Vienna Ab initio Simulation Package (VASP) code. Phonon calculations were performed on the stable structure obtained by the structural optimization calculations using the first-principles perturbation calculation method (DFPT method). As described in the following literature, the DFPT method is a method of applying an electric field to a crystal as a perturbation and calculating the change in polarization in order to quantify the dielectric constant of a single crystal dielectric. The relative dielectric constant ε of each complex oxide was calculated using the python package pymatgen from the results of the phonon calculations. r In addition, the band gap E g The results are shown in Table 3.

[0069] Stefano Baroni et al. “Phonons and related crystal properties from density-functional perturbation theory”, REVIEWS OF MODERN PHYSICS, VOLUME 73, 2001 The validity of the above calculation of the dielectric constant was verified as follows. The dielectric constants at -273°C of BaTa2O6 described in Non-Patent Document 1 and BaNb2O6 described in Non-Patent Document 2 were calculated according to the above calculation. The calculated values ​​of the dielectric constant were compared with the measured values ​​described in Non-Patent Documents 1 and 2. The results are shown in Table 2. As shown in Table 2, the calculated values ​​can be considered to be equivalent to the measured values, the above calculation is valid, and the calculated values ​​of the dielectric constant obtained by the above calculation are considered to be equivalent to the measured values.

[0070] [Table 2]

[0071] (Evaluation of dielectric breakdown field) Band gap E obtained from first-principles calculationsg The dielectric breakdown field E of each composite oxide at -273°C was calculated based on the following formulas (1a) and (1b) with reference to Wang, Li-Mo. "Relationship between Intrinsic Breakdown Field and Bandgap of Materials." 2006 25th International Conference on Microelectronics. IEEE, 2006. In the following formulas, E and E g The units are V / nm and eV, respectively. The calculation results are shown in Table 3.

[0072] E = 1.36 × (E g / 4) 3 (E g <4) Equation (1a) E = 1.36 × (E g / 4) (E g ≧4) Equation (1b) (Energy density evaluation) The relative dielectric constant ε of each composite oxide calculated as above r Based on the dielectric breakdown field E [V / nm], the energy density W of each composite oxide was calculated using the following formula (2). In formula (2), ε0 is the dielectric constant of a vacuum, and the unit of the energy density W is [Wh / liter (L)]. The results are shown in Table 3.

[0073] W = (1 / 7.2) x 10 12 ε0 ε r (E) 2 Formula (2) <Reference example> 3 g of raw material powder containing Cs2CO3, TiO2, and WO3 was prepared so that the condition of Cs2CO3 mass amount: TiO2 mass amount: WO3 mass amount = 1:1:3 was satisfied. This raw material powder was pulverized and mixed in a mortar. The mixed powder thus obtained was placed in a pressure molding die and pressed at a pressure of 20 MPa to produce a pellet. The obtained pellet was fired in air at 850°C for 80 hours. The fired pellet was pulverized again in a mortar to obtain a powdered composite oxide according to the reference example. The composite oxide according to the reference example was CsTi 0.5 W 1.5 It had a composition represented as O6.

[0074] In order to identify the crystal structure of the composite oxide according to the reference example, an X-ray diffraction (XRD) measurement was carried out. In this measurement, Cu-Kα radiation was used as the X-ray, and the measurement was carried out in a dry argon atmosphere. FIG. 8 is a graph showing the XRD pattern of the composite oxide according to the reference example. In this graph, the horizontal axis indicates the diffraction angle 2θ, and the vertical axis indicates the X-ray diffraction intensity. FIG. 8 shows the XRD pattern of Cs2TiW3O obtained from the Inorganic Crystal Structure Database (ICSD). 12 The reference data for the X-ray diffraction pattern of the composite oxide of the reference example is Cs2TiW3O obtained from ICSD. 12 This coincided with the reference data for the X-ray diffraction pattern of the composite oxide according to the reference example. This suggests that the composite oxide according to the reference example has a pyrochlore type crystal structure.

[0075] According to the first-principles calculation method explained in the section on calculating the relative dielectric constant above, 0.5 W 1.5 We performed structural optimization calculations for a composite oxide with the composition of CeTiO6. 0.5 W 1.5 Figure 9 shows the stable structure of O6. 0.5 W 1.5 It was suggested that the complex oxide with the O6 composition has a pyrochlore type crystal structure.

[0076] According to the first-principles calculation method described in the section on calculation of the relative dielectric constant above, a structural optimization calculation was carried out for a composite oxide having the following composition.

[0077] CsSi 0.5 W 1.5 O6 CsGe 0.5 W 1.5 O6 CsSn 0.5 W 1.5 O6 KSi 0.5 W 1.5 O6 KGe 0.5 W 1.5 O6 K.S.n 0.5 W 1.5 O6 RbSi 0.5 W 1.5 O6 RbGe 0.5 W 1.5 O6 RbSn 0.5 W 1.5 O6 FIG. 10A shows the structure of CeSi 0.5 W 1.5 FIG. 10B shows the stable structure of CeGeO6. 0.5 W 1.5 FIG. 10C shows the stable structure of CeSnO6. 0.5 W 1.5 FIG. 10D shows the stable structure of KSi 0.5 W 1.5 FIG. 10E shows the stable structure of KGe 0.5 W 1.5 FIG. 10F shows the stable structure of KSnO6. 0.5 W 1.5 FIG. 10G shows the stable structure of RbSi 0.5 W 1.5 FIG. 10H shows the stable structure of RbGeO6. 0.5 W 1.5 FIG. 10I shows the stable structure of RbSn 0.5 W 1.5 9 and 10A to 10I show the stable structure of CsSi0.5 W 1.5 O6, CsGe 0.5 W 1.5 O6, CsSn 0.5 W 1.5 O6, KSi 0.5 W 1.5 O6, KGe 0.5 W 1.5 O6, KSn 0.5 W 1.5 O6, RbSi 0.5 W 1.5 O6, RbGe 0.5 W 1.5 O6 and RbSn 0.5 W 1.5 It was suggested that O6 has a pyrochlore type crystal structure.

[0078] As shown in Table 3, it was suggested that a composite oxide composed of at least one selected from the group consisting of K, Rb, and Cs, at least one selected from the group consisting of Si, Ge, and Sn, and at least one selected from the group consisting of Mo and W has a higher relative dielectric constant than BaTa2O6 and BaNb2O6. In addition, it was suggested that the dielectric breakdown field of these composite oxides is high. Furthermore, it was suggested that these composite oxides have a high energy density. It is understood that a capacitor having a dielectric containing such a composite oxide is advantageous in terms of capacitance and dielectric breakdown field.

[0079] [Table 3] [Industrial Applicability]

[0080] The capacitors of the present disclosure are useful in terms of capacitance and dielectric breakdown field. [Explanation of symbols]

[0081] 1a, 1b, 1c, 1d capacitors 3 Electrical Circuits 5 Circuit Board 7 Equipment 11 First electrode 12 Second electrode 20 Dielectrics

Claims

1. A first electrode; A second electrode; a dielectric material including a complex oxide and disposed between the first electrode and the second electrode; The composite oxide is At least one selected from the group consisting of K, Rb, and Cs; At least one selected from the group consisting of Si, Ge, and Sn; At least one selected from the group consisting of Mo and W; Capacitor.

2. The composite oxide is Consisting of any one of K, Rb, and Cs; The capacitor of claim 1 .

3. The composite oxide is composed of any one of Cs and K. The capacitor of claim 1 .

4. The composite oxide is Consisting of any one of Si, Ge, and Sn; The capacitor of claim 1 .

5. The composite oxide is Consisting of any one of Mo and W; The capacitor of claim 1 .

6. The composite oxide is A α B β C γ O δ The composition is represented by In the composition, A is at least one selected from the group consisting of K, Rb, and Cs; B is at least one selected from the group consisting of Si, Ge, and Sn; C is at least one selected from the group consisting of Mo and W; The composition satisfies the conditions of 0.9≦α≦1.1, 0.25≦β≦1, 1≦γ≦2, and 5.5≦δ≦6.

5. The capacitor of claim 1 .

7. The composite oxide has a pyrochlore type crystal structure. The capacitor of claim 1 .

8. Contains a complex oxide, The composite oxide is At least one selected from the group consisting of K, Rb, and Cs; At least one selected from the group consisting of Si, Ge, and Sn; At least one selected from the group consisting of Mo and W; Dielectric for capacitors.

9. An electric circuit comprising a capacitor according to any one of claims 1 to 7.

10. A circuit board comprising the capacitor according to claim 1 .

11. An apparatus comprising a capacitor according to any one of claims 1 to 7.

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