阅读说明：本技术 电介质组合物和电子部件 (Dielectric composition and electronic component ) 是由 井口俊宏 于 2020-02-12 设计创作，主要内容包括：本发明提供一种电介质组合物,其包含由通式A<Sub>a</Sub>B<Sub>b</Sub>C<Sub>4</Sub>O<Sub>15+α</Sub>表示的具有钨青铜结构的复合氧化物作为主要成分,A至少包含Ba,B至少包含Zr,C至少包含Nb,a为3.05以上,b为1.01以上。在该电介质组合物中,当将占据钨青铜结构的M2位点的原子总数设为1时,B所占的比例为0.250以上。另外,在该电介质组合物中,钨青铜结构的(410)面的X射线衍射峰分裂成2个,表示X射线衍射峰的高角度侧峰的积分强度相对于X射线衍射峰的低角度侧峰的积分强度的积分强度比率为0.125以上。(The invention provides a dielectric composition comprising a compound represented by the general formula A a B b C 4 O 15+α The composite oxide having a tungsten bronze structure is represented by A containing at least Ba, B containing at least Zr, C containing at least Nb, a being 3.05 or more and B being 1.01 or more. In the dielectric composition, when the total number of atoms occupying M2 sites of the tungsten bronze structure is 1, the proportion of B is 0.250 or more. In addition, in the dielectric composition,the X-ray diffraction peak of the (410) plane of the tungsten bronze structure is split into 2 pieces, and the ratio of the integrated intensity of the high-angle side peak of the X-ray diffraction peak to the integrated intensity of the low-angle side peak of the X-ray diffraction peak is 0.125 or more.)

1. A dielectric composition characterized in that,

comprising a compound represented by the general formula A_aB_bC₄O_15+αThe complex oxide represented is used as a main component,

said A comprising at least barium, said B comprising at least zirconium, said C comprising at least niobium,

wherein a is 3.05 or more, b is 1.01 or more,

the composite oxide has a tungsten bronze structure,

in the tungsten bronze structure, when the total number of atoms occupying the M2 site is 1, the proportion of B is 0.250 or more.

2. The dielectric composition of claim 1,

the proportion of B is more than 0.400.

3. The dielectric composition of claim 1 or 2,

the general formula is represented by (Ba)_1-xA1_x)_a(Zr_1-yB1_y)_b(Nb_1-zC1_z)₄O_15+αIt is shown that,

the A1 comprises more than 1 selected from calcium and strontium, the B1 comprises titanium, the C1 comprises tantalum,

the x is 0.50 or less, the y is 0.25 or less, and the z is 0.50 or less.

4. The dielectric composition of claim 1 or 2,

the a is 3.10 or more.

5. The dielectric composition of claim 1 or 2,

and b is 1.05 or more.

6. A dielectric composition characterized in that,

comprising a compound represented by the general formula A_aB_bC₄O_15+αThe complex oxide represented is used as a main component,

said A comprising at least barium, said B comprising at least zirconium, said C comprising at least niobium,

wherein a is 3.05 or more, b is 1.01 or more,

the composite oxide has a tungsten bronze structure,

the X-ray diffraction peak of the (410) plane of the tungsten bronze structure is split into 2 pieces, and the ratio of the integrated intensity of the high-angle side peak of the X-ray diffraction peak to the integrated intensity of the low-angle side peak of the X-ray diffraction peak is 0.125 or more.

7. The dielectric composition of claim 6,

the integrated intensity ratio is 0.200 or more.

8. The dielectric composition of claim 6 or 7,

the general formula is represented by (Ba)_1-xA1_x)_a(Zr_1-yB1_y)_b(Nb_1-zC1_z)₄O_15+αIt is shown that,

the A1 comprises more than 1 selected from calcium and strontium, the B1 comprises titanium, the C1 comprises tantalum,

the x is 0.50 or less, the y is 0.25 or less, and the z is 0.50 or less.

9. The dielectric composition of claim 6 or 7,

the a is 3.10 or more.

10. The dielectric composition of claim 6 or 7,

and b is 1.05 or more.

11. An electronic component characterized in that, in a case,

the disclosed device is provided with: a dielectric layer comprising the dielectric composition of any one of claims 1 to 10, and an electrode layer.

Technical Field

The present invention relates to a dielectric composition and an electronic component including a dielectric layer formed of the dielectric composition.

Background

Many electronic components such as a multilayer ceramic capacitor having dielectric characteristics expressed by a dielectric are mounted in an electronic circuit or a power supply circuit incorporated in an electronic device. As a material (dielectric material) constituting a dielectric of such an electronic component, a barium titanate-based dielectric composition is widely used.

However, in recent years, the use of electronic components has been expanding, and for example, it is required that electronic components function sufficiently even in a high-temperature or high-voltage environment. However, in such an environment, the dielectric characteristics of the barium titanate-based dielectric composition are degraded, and the barium titanate-based dielectric composition cannot sufficiently cope with the environment. Therefore, a dielectric composition that can exhibit high dielectric characteristics even in such applications is being sought.

Patent document 1 discloses a dielectric composition other than a barium titanate-based dielectric composition, which is represented by the general formula Ba₆Ti₂Nb₈O₃₀The ferroelectric material shown in the figure is a dielectric composition in which a part of Ba, Ti and Nb is substituted with other elements.

Disclosure of Invention

Technical problem to be solved by the invention

For the dielectric material, high dielectric characteristics (e.g., relative permittivity) are required. The dielectric characteristics are those based on an insulator. Therefore, the dielectric material is required to have a high resistivity so that the dielectric composition is not semiconductive or conductive.

In view of the above-described situation, an object of the present invention is to provide a dielectric composition capable of improving the relative permittivity while maintaining the resistivity, and an electronic component including a dielectric layer formed of the dielectric composition.

Means for solving the problems

In order to achieve the above object, the dielectric composition of the present invention is:

[1] a dielectric composition characterized in that,

comprising a compound represented by the general formula A_aB_bC₄O_15+αThe complex oxide represented is used as a main component,

a contains at least barium, B contains at least zirconium, C contains at least niobium,

a is 3.05 or more, b is 1.01 or more,

the composite oxide has a tungsten bronze structure,

in the tungsten bronze structure, when the total number of atoms occupying the M2 site is 1, the proportion of B is 0.250 or more.

[2] The dielectric composition according to [1], characterized in that,

the proportion of B is more than 0.400.

[3] A dielectric composition characterized in that,

comprising a compound represented by the general formula A_aB_bC₄O_15+αThe complex oxide represented is used as a main component,

a contains at least barium, B contains at least zirconium, C contains at least niobium,

a is 3.05 or more, b is 1.01 or more,

the composite oxide has a tungsten bronze structure,

the X-ray diffraction peak of the (410) plane of the tungsten bronze structure is split into 2 pieces, and the ratio of the integrated intensity of the high-angle side peak of the X-ray diffraction peak to the integrated intensity of the low-angle side peak of the X-ray diffraction peak is 0.125 or more.

[4] The dielectric composition according to [3], characterized in that,

the integrated intensity ratio is 0.200 or more.

[5] The dielectric composition according to any one of [1] to [4], wherein the dielectric composition,

general formula (Ba)_1-xA1_x)_a(Zr_1-yB1_y)_b(Nb_1-zC1_z)₄O_15+αIt is shown that,

a1 contains more than 1 selected from calcium and strontium, B1 contains titanium, C1 contains tantalum,

x is 0.50 or less, y is 0.25 or less, and z is 0.50 or less.

[6] The dielectric composition according to any one of [1] to [5],

a is 3.10 or more.

[7] The dielectric composition according to any one of [1] to [6],

b is 1.05 or more.

[8] An electronic component characterized in that, in a case,

the disclosed device is provided with: a dielectric layer comprising the dielectric composition according to any one of [1] to [7], and an electrode layer.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a dielectric composition capable of improving the relative permittivity while maintaining the resistivity, and an electronic component including a dielectric layer formed of the dielectric composition can be provided.

Drawings

Fig. 1 is a sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention.

Fig. 2 is a schematic view showing a tungsten bronze structure viewed from the c-axis direction.

Fig. 3 (a) and (B) are diagrams showing X-ray diffraction peaks of the (410) plane of the tungsten bronze structure.

Fig. 4 (a) is a graph showing the result of separating the X-ray diffraction peak of the (410) plane shown in fig. 3 (a) into 2 peaks by the Voigt function. Fig. 4 (B) is a graph showing the result of separating the X-ray diffraction peak of the (410) plane shown in fig. 3 (B) into 2 peaks by the Voigt function.

Description of symbols:

1 … … laminated ceramic capacitor

10 … … element body

2 … … dielectric layer

3 … … internal electrode layer

4 … … external electrode

X-ray diffraction peak of (410) plane of P … … tungsten bronze structure

P1 … … Low Angle side Peak

P2 … … high angle side peak

Detailed Description

Hereinafter, the present invention will be described in detail based on specific embodiments in the following order.

1. Multilayer ceramic capacitor

1.1 monolithic Structure of laminated ceramic capacitor

1.2 dielectric layer

1.3 internal electrode layers

1.4 external electrodes

2. Dielectric composition

2.1 composite oxides

3. Method for manufacturing multilayer ceramic capacitor

4. Summary of the present embodiment

5. Modification example

(1. multilayer ceramic capacitor)

(1.1 monolithic Structure of multilayer ceramic capacitor)

Fig. 1 shows a multilayer ceramic capacitor 1 as an example of an electronic component according to the present embodiment. The multilayer ceramic capacitor 1 includes: and an element body 10 having a structure in which the dielectric layers 2 and the internal electrode layers 3 are alternately stacked. A pair of external electrodes 4 that are electrically connected to the internal electrode layers 3 alternately arranged inside the device main body 10 are formed on both end portions of the device main body 10. The shape of the element body 10 is not particularly limited, and is generally a rectangular parallelepiped shape. The size of the element body 10 is not particularly limited, and may be set to an appropriate size according to the application.

(1.2 dielectric layer)

The dielectric layer 2 is made of a dielectric composition according to the present embodiment described later. The thickness of each dielectric layer 2 (interlayer thickness) per 1 layer is not particularly limited, and may be arbitrarily set according to desired characteristics, application, and the like. The interlayer thickness is usually preferably 100 μm or less, more preferably 30 μm or less. The number of stacked dielectric layers 2 is not particularly limited, but in the present embodiment, for example, is preferably 20 or more.

(1.3 internal electrode layers)

In the present embodiment, the internal electrode layers 3 are stacked so that the end surfaces are alternately exposed to the surfaces of the opposing 2 end portions of the element main body 10.

The conductive material contained as the internal electrode layers 3 is not particularly limited. Either a base metal or a noble metal. The base metal is not particularly limited, and known conductive materials such as Ni, Ni-based alloys, Cu, and Cu-based alloys can be used. In addition, Ni-based alloys, Cu, or Cu-based alloys may contain various trace components such as about 0.1 mass% or less of P. The noble metal is not particularly limited, and a known conductive material such as Pd, Pt, Ag — Pd alloy, or the like can be used. The internal electrode layers 3 may be formed using a commercially available paste for electrodes. The thickness of the internal electrode layers 3 may be determined as appropriate depending on the application.

(1.4 external electrode)

The conductive material contained in the external electrode 4 is not particularly limited. For example, known conductive materials such as Ni, Cu, Sn, Ag, Pd, Pt, Au, alloys thereof, and conductive resins can be used. The thickness of the external electrode 4 may be determined as appropriate depending on the application.

(2. dielectric composition)

The dielectric composition according to the present embodiment contains, as a main component, a composite oxide containing at least barium (Ba), zirconium (Zr), and niobium (Nb). That is, in the present embodiment, the composite oxide is contained in an amount of preferably 80 mass% or more, and more preferably 90 mass% or more, based on 100 mass% of the dielectric composition according to the present embodiment.

(2.1 Complex oxide)

The composite oxide has a tungsten bronze structure. Specifically, the composite oxide has a tungsten bronze structure belonging to space group P4 bm. Fig. 2 shows a tungsten bronze structure viewed from the c-axis direction. As shown in fig. 2, in the tungsten bronze structure, a three-dimensional network in which oxygen octahedrons 51 and 52 share vertices with each other is formed, wherein the oxygen octahedrons 51 are formed by oxygen being hexacoordinated to an element occupying position 21 of M1, and the oxygen octahedrons 52 are formed by oxygen being hexacoordinated to an element occupying position 22 of M2. Further, elements occupying Al sites 31 and a2 sites 32 are located in the interstitial spaces of oxygen octahedra.

In addition, the composite oxide is represented by the general formula A_aB_bC₄O_15+αAnd (4) showing. In the formula, "A", "B" and "C" are divided on the basis of valence.That is, elements other than oxygen contained in the composite oxide are divided into 3 element groups ("a", "B", and "C") based on the valence. "A" is a 2-valent element comprising barium. "B" is a 4-valent element comprising zirconium. "C" is a 5-valent element comprising niobium.

In the present embodiment, "a" occupies a 1-site and a 2-site, and "B" and "C" occupy M1-site and M2-site in the tungsten bronze structure.

In Table 1, as A_aB_bC₄O_15+αShows that when zirconium and niobium occupy Ba in the same ratio₃ZrNb₄O₁₅The M1 site and the M2 site. The atomic arrangement shown in Table 1 was obtained by the national research and development institute of human Material and Material, inorganic Material database "AtomWork" [ Japanese Highui 31 years, 3 months, 11 days search]And the Internet URL is obtained by http:// crystdb. nims. go. jp.

[ Table 1]

Atomic coordinates

In table 1, "Ba 1" and "Ba 2" are denoted as a1 site and a2 site, respectively, in the present specification.

As shown in fig. 2, the oxygen octahedron 51 centered at the M1 site is slightly distorted compared to the oxygen octahedron 52 centered at the M2 site. The dielectric characteristics (e.g., relative dielectric constant) due to this deformation are improved, and since the skew becomes larger when "C" occupies the M1 site, it is preferable.

On the other hand, the present inventors have found that in "B" and "C", the "B" readily occupies the M1 site. Further, when "B" occupies the M1 site, even if an electric field is applied to the composite oxide, "B" having a small valence is hard to move, and polarization is small. In contrast, when "C" occupies the M1 site, since its valence is larger than "B", it is easy to move and polarization is large when an electric field is applied.

That is, the present inventors found that the smaller the ratio of "B" in the M1 site, the more improved the dielectric characteristics due to polarization. Conversely, the larger the ratio of "B" in the M2 site, the more improved the dielectric characteristics.

Therefore, in the present embodiment, the ratio of "B" at the M2 site is set to a predetermined value or more. Specifically, when the total number of atoms occupying the M2 site is 1, the proportion of "B" is 0.250 or more. The proportion of "B" is preferably 0.400 or more, and more preferably 0.500 or more.

By setting the ratio of "B" in the M2 site to the above range, the relative permittivity tends to be improved as compared with the case where the ratio of "B" in the M2 site is low.

In addition, the present inventors have found that the dielectric characteristics (e.g., relative permittivity) are improved by controlling the shape of the X-ray diffraction peak of the (410) plane of the tungsten bronze structure. Specifically, the dielectric characteristics were improved by splitting the X-ray diffraction peak of the (410) plane into 2 and making the high-angle side peak larger than the low-angle side peak. In addition, the X-ray diffraction peak of the (410) plane of the tungsten bronze structure is usually a strong peak at the 2 nd peak, and appears in a range of 28 ° to 29.5 ° in the X-ray diffraction measurement using Cu — K α rays as an X-ray source.

In the present embodiment, the integrated intensity (area) of the low-angle side peak and the integrated intensity (area) of the high-angle side peak are calculated, and the integrated intensity (integrated intensity ratio) of the high-angle side peak with respect to the integrated intensity of the low-angle side peak is calculated. The larger the integrated intensity ratio is, the higher the relative dielectric constant tends to be. In the present embodiment, the integrated intensity ratio is 0.125 or more. The integrated intensity ratio is preferably 0.200 or more, more preferably 0.250 or more.

When the diffraction peak on the (410) plane is split into 2, the peak leg of the low-angle side peak and the peak leg of the high-angle side peak are overlapped with each other in general, and it is difficult to calculate the integrated intensity (area) of each peak. Therefore, in order to calculate the integrated intensity of each peak, in the present embodiment, the diffraction peak of the (410) plane is separated using the sum of 2 Voigt functions.

The Voigt function is a distribution function obtained by convolution of a gaussian function and a lorentzian function, and is used for fitting an X-ray diffraction peak, a spectroscopic spectrum, and the like. The diffraction peak of the (410) plane is expressed as a synthesized peak of 2 peaks (low-angle side peak and high-angle peak) by minimizing the square error of the sum of the experimental data of the diffraction peak of the (410) plane and the 2 Voigt functions by fitting.

In this embodiment, the parameters and multiples of each Voigt function are optimized such that the sum of the 2 Voigt functions has the smallest squared error with the experimental data. Any optimization solver may be used for the optimization. The Voigt function may be calculated by well-known software. In addition, the optimization solver may use a known algorithm or software.

Fig. 3 (a) shows an X-ray diffraction pattern in which the X-ray diffraction peak of the (410) plane is a single one, and fig. 3 (B) shows an X-ray diffraction pattern in which the X-ray diffraction peak of the (410) plane is split into 2. The results obtained by separating the X-ray diffraction peak of the (410) plane shown in (a) and (B) of fig. 3 into 2 diffraction peaks by the Voigt function are shown in (a) and (B) of fig. 4, respectively.

As shown in (B) of fig. 4, by using the Voigt function, the X-ray diffraction peak P of the (410) plane can be separated into a low-angle side peak P1 and a high-angle side peak P2. Then, the integrated intensity of the low-angle side peak P1 and the integrated intensity of the high-angle side peak P2 can be calculated, and an integrated intensity ratio (integrated intensity of the high-angle side peak P2/integrated intensity of the low-angle side peak P1) can be calculated. As is clear from fig. 4 (a), when the diffraction peak P of the (410) plane is a single one, it is constituted only by the low-angle side peak P1. Therefore, the integrated intensity ratio is 0.

The inventors found that the integrated intensity ratio correlates with the ratio of "B" in the M2 locus. That is, the split of the diffraction peak of the (410) plane correlates with the ratio of "B" in the M2 site. Specifically, the relationship of "B" at the position M2 is established as the integrated intensity ratio × 2. That is, the ratio of "B" in the M2 locus can be calculated from the integrated intensity ratio.

As described above, the composite oxide is represented by the general formula A_aB_bC₄O_15+αAnd (4) showing. "a" in the general formula represents the atomic number ratio of "A" in the case where the element constituting "C" contains 4 atoms in the general formula, and the above general formula"B" in the formula represents the atomic number ratio of "B" in the case where the element constituting "C" includes 4 atoms in the general formula.

In the present embodiment, "a" is 3.05 or more, preferably 3.10 or more. The upper limit of "a" is not particularly limited as long as the effect of the present invention can be obtained, and is, for example, preferably 3.50 or less, and more preferably 3.30 or less.

In the present embodiment, "b" is 1.01 or more, preferably 1.05 or more. The upper limit of "b" is not particularly limited as long as the effect of the present invention can be obtained, and is, for example, preferably 1.50 or less, and more preferably 1.30 or less.

Therefore, the above-mentioned composite oxide can be said to consist of the general formula A in the stoichiometric composition₃B₁C₄O₁₅The composite oxides represented herein include "a" and "B" in excess of "C" in a predetermined ratio. When "a" and "b" are in the above range, the composite oxide can exhibit a high specific resistance even when fired in a reducing atmosphere. As will be described later in detail, the ratio of "B" in the M2 site and the ratio of integrated intensity are easily made to fall within the above ranges by firing in a reducing atmosphere.

The main factor that can be used to obtain a composite oxide having a high resistivity by setting "a" and "b" within the above-described ranges is, for example, as follows. When fired in a reducing atmosphere₃B₁C₄O₁₅In the case of the composite oxide represented, oxygen is deprived from the composite oxide, and oxygen defects and free electrons are generated in pairs. As a result, it is considered that the generated free electrons move to generate conductivity, thereby lowering the resistivity of the composite oxide.

Here, by making "a" and "B" present in excess of "C", the ratio of B among the sites occupied by "B" and "C" (M1 site and M2 site) becomes large. In other words, "B" is considered to replace "C". As described above, "B" is a 4-valent element and "C" is a 5-valent element, so when "B" substitutes for "C", the valence equilibrium with oxygen is broken, oxygen defects are generated, but free electrons are not generated. As a result, in the composite oxide, since oxygen defects are present to some extent, the reaction of generating oxygen defects accompanying reduction firing does not easily proceed. That is, even in a reducing atmosphere, a reaction of depriving oxygen from the composite oxide hardly occurs. Therefore, since free electrons are less likely to be generated, it is considered that the decrease in resistivity is suppressed.

In addition, in the composite oxide, the amount of oxygen (O) may vary depending on the structural ratio of "a", "B", and "C", oxygen defects, and the like. Thus, in this embodiment, the compounds represented by formula A₃B₁C₄O₁₅The deviation of oxygen from the stoichiometric ratio is represented by "α" based on the stoichiometric ratio of the complex oxide, and the range of "α" is not particularly limited, and is, for example, about-1 to 1.

In the present embodiment, "a" contains at least barium, but may contain a 2-valent element a1 other than barium. "A1" preferably contains 1 or more kinds selected from calcium and strontium. When "a 1" is included in "a" in addition to barium, the composite oxide according to the present embodiment may be represented by (Ba)_1-xA1_x)_aB_bC₄O_15+α. In the formula, "x" is preferably 0.00 or more. On the other hand, "x" is preferably 0.50 or less, more preferably 0.25 or less. Even if "a 1" is contained in "a", appropriate dielectric characteristics can be obtained.

"B" includes at least zirconium, but may include a 4-valent element B1 other than zirconium. "B1" preferably comprises titanium. When "B1" is included in "B" in addition to zirconium, the composite oxide according to the present embodiment may be represented by a_a(Zr_1-yB1_y)_bC₄O_15+α. In the formula, "y" is preferably 0.00 or more. On the other hand, "y" is preferably 0.50 or less, more preferably 0.25 or less. Even if "B1" is included in "B", appropriate dielectric characteristics can be obtained.

In addition, when titanium is included as "B1", the resistivity tends to decrease. Therefore, in the present embodiment, titanium is preferably contained to such an extent that the effects of the present invention can be obtained. Specifically, when the total number of atoms constituting "B" is 1, the ratio of the number of atoms of titanium is preferably 0.25 or less, and more preferably 0.125 or less. From the viewpoint of obtaining high resistivity, it is preferable that substantially no titanium is contained. Here, "substantially no titanium" means that titanium may be contained to the extent of an amount due to unavoidable impurities.

Further, "C" includes at least niobium, but may include a 5-valent element C1 other than niobium. "C1" preferably comprises tantalum. When "C1" is included in "C" in addition to niobium, the composite oxide according to the present embodiment may be represented by a_aB_b(Nb_{1- z}C1_z)₄O_15+α. In the formula, "z" is preferably 0.00 or more. On the other hand, "z" is preferably 0.50 or less, more preferably 0.25 or less. Even if "C1" is included in "C", appropriate dielectric characteristics can be obtained.

When the total number of atoms constituting "a" is 1, the ratio of the number of atoms of the 2-valent element a1 excluding calcium and strontium is preferably 0.10 or less. When the total number of atoms constituting "B" is 1, the ratio of the number of atoms of the 4-valent element B1 excluding titanium is preferably 0.10 or less. When the total number of atoms constituting "C" is 1, the ratio of the number of atoms of the 5-valent element C1 excluding tantalum is preferably 0.10 or less.

Thus, formula A_aB_bC₄O_15+αCan be prepared from (Ba)_1-xA1_x)_a(Zr_1-yB1_y)_b(Nb_1-zC1_z)₄O_15+αThe expressions "a", "b", "x", "y", "z" and "α" are used in the above-mentioned ranges.

The dielectric composition according to the present embodiment may contain other components in addition to the composite oxide, within a range that achieves the effects of the present invention. The content of the other components is preferably 20% by mass or less, and more preferably 10% by mass or less, of 100% by mass of the dielectric composition. In particular, from SiO₂、MnO、CuO、Fe₂O₃And Bi₂O₃The total content of 1 or more components in (b) is preferably 0.5% by mass or less based on 100% by mass of the dielectric composition. This is because these components lower the sinterability of the dielectric composition and lower the dielectric characteristics and physical properties of the dielectric composition.

(3. method for producing multilayer ceramic capacitor)

Next, an example of a method for manufacturing the laminated ceramic capacitor 1 shown in fig. 1 will be described below.

The laminated ceramic capacitor 1 according to the present embodiment can be manufactured by a known method similar to a conventional laminated ceramic capacitor. As a known method, for example, a method of manufacturing a multilayer ceramic capacitor by preparing a green chip using a paste containing a raw material of a dielectric composition and firing the green chip is exemplified. Hereinafter, the production method will be specifically described.

First, a starting material of the dielectric composition is prepared. As the starting material, a composite oxide constituting the above dielectric composition can be used. In addition, oxides of the respective metals contained in the composite oxide may be used. In addition, various compounds which become components constituting the composite oxide by firing can be used. Examples of the various compounds include carbonates, oxalates, nitrates, hydroxides, and organic metal compounds. In the present embodiment, the starting material is preferably a powder.

The raw materials of the composite oxide in the prepared starting materials are weighed in a predetermined ratio and wet-mixed for a predetermined time by using a ball mill or the like. And drying the mixed powder, and then carrying out heat treatment in the air at the temperature of 700-1300 ℃ to obtain the calcined powder of the composite oxide.

Subsequently, a paste for producing a green chip was prepared. The obtained calcined powder, binder and solvent were kneaded and coated to prepare a dielectric layer paste. Known binders and solvents may be used. The dielectric layer paste may contain additives such as a plasticizer and a dispersant as needed.

The internal electrode layer paste can be obtained by kneading the raw material of the conductive material, the binder, and the solvent. Known binders and solvents may be used. The internal electrode layer paste may contain additives such as common materials and plasticizers, as necessary.

The external electrode layer paste may be prepared in the same manner as the internal electrode layer paste.

Using the obtained pastes, green sheets and internal electrode patterns were formed, and they were laminated to obtain green chips.

The green chip obtained is subjected to a binder removal treatment as necessary. The binder removal treatment conditions may be known conditions, and for example, the holding temperature is preferably set to 200 to 350 ℃.

After the binder removal treatment, the green chip is fired to obtain an element body. In the present embodiment, firing in a reducing atmosphere (reduction firing) is performed so that the ratio of "B" in the M2 site and the integral intensity ratio fall within the above ranges. Oxygen partial pressure (pO) in a reducing atmosphere₂) Preferably 1 × 10^-7Pa or less, more preferably 1 × 10^-8Pa or less. Other firing conditions may be known, and for example, the holding temperature is preferably set to 1200 to 1450 ℃.

After firing, the obtained element body is preferably subjected to re-oxidation treatment (annealing). The annealing conditions may be known conditions, and for example, it is preferable to set the oxygen partial pressure at the time of annealing to an oxygen partial pressure higher than the oxygen partial pressure at the time of firing and to set the holding temperature to 1150 ℃ or lower. In particular, since the oxygen partial pressure in the reducing atmosphere during firing is closer to 0, more oxygen defects are generated in the dielectric composition, it is preferable to extend the annealing time in order to compensate for the oxygen defects.

The dielectric composition constituting the dielectric layer of the device body obtained as described above is the above-described dielectric composition. This element body was subjected to end face polishing, applied with an external electrode paste and fired to form external electrodes 4. Then, if necessary, a coating layer is formed on the surface of the external electrode 4 by plating or the like.

By such a method, the multilayer ceramic capacitor according to the present embodiment is manufactured.

(4. summary of the present embodiment)

The present inventors have found that, when the 4-valent element "B" and the 5-valent element "C" contained in the composite oxide having a tungsten bronze structure occupy the M1 site and the M2 site of the tungsten bronze structure, the greater the proportion of "B" located at the M2 site, the higher the dielectric characteristics, in particular, the relative dielectric constant.

This is considered to be due to the fact that the dielectric properties due to structural deformation of an oxygen octahedron containing "C" at the M1 site are larger than those in the case where "C" is located at the M1 site.

The inventors of the present invention paid attention to the X-ray diffraction peak of the (410) plane of the tungsten bronze structure, and found that the dielectric characteristics, particularly the relative dielectric constant, are higher when the peak is split into 2 and the area of the high-angle side peak is larger.

Further, the present inventors have found that the proportion of "B" located at the M2 site is correlated with the area of the high-angle side peak of the X-ray diffraction peak of the (410) plane. As a result, the ratio of "B" at the M2 site and the area of the high-angle side peak satisfy the above relationship.

In order to obtain such an effect, it is necessary to fire the dielectric composition in a reducing atmosphere. Therefore, the dielectric composition according to the present embodiment includes the 2-valent element "a" and the 4-valent element "B" in an excess amount to the 5-valent element "C" to impart reduction resistance to the dielectric composition. As a result, a dielectric composition having an improved relative permittivity while maintaining resistivity can be obtained.

(5. modification)

In the above-described embodiments, the case where the electronic component according to the present invention is a laminated ceramic capacitor was described, but the electronic component according to the present invention is not limited to the laminated ceramic capacitor, and may be any electronic component having the above-described dielectric composition.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and may be changed in various ways within the scope of the present invention.