KR102585979B1 - Ceramic dielectric and method of manufacturing the same and ceramic electronic component and electronic device - Google Patents

Abstract

A bulk dielectric containing barium (Ba) and titanium (Ti), a ceramic nanosheet, a ceramic dielectric containing a composite dielectric of the bulk dielectric and the ceramic nanosheet, and a method of manufacturing the same, a ceramic electronic component containing a ceramic dielectric, and It's about electronic devices.

Description

Ceramic dielectric and its manufacturing method, ceramic electronic components and electronic devices {CERAMIC DIELECTRIC AND METHOD OF MANUFACTURING THE SAME AND CERAMIC ELECTRONIC COMPONENT AND ELECTRONIC DEVICE}

Pertains to ceramic dielectrics and their manufacturing methods, ceramic electronic components and electronic devices.

Electronic components that use ceramics include capacitors, inductors, piezoelectric elements, varistors, or thermistors. Among these, capacitors are electronic components used to obtain electrostatic capacity and are important elements that make up electronic circuits. A multi-layer ceramic capacitor (MLCC), an example of a capacitor, contains a plurality of capacitors and is manufactured in the form of a chip, for example, to be used on printed circuit boards of various electronic devices such as imaging devices such as liquid crystal displays, computers, and mobile phones. It can be mounted to play a role in charging or discharging electricity, and can be used in coupling, decoupling, and impedance matching devices.

Recently, as electronic devices are required to be highly functional, efficient, and miniaturized, ceramic electronic components such as multilayer ceramic capacitors installed in electronic devices are also required to be highly functional and miniaturized.

One embodiment provides a ceramic dielectric having both high dielectric constant and high resistivity.

Another embodiment provides a method for manufacturing the ceramic dielectric.

Another embodiment provides a ceramic electronic component including the ceramic dielectric.

Another embodiment provides an electronic device including the ceramic electronic component.

According to one embodiment, a ceramic dielectric including a bulk dielectric including barium (Ba) and titanium (Ti), a ceramic nanosheet, and a composite dielectric of the bulk dielectric and the ceramic nanosheet is provided.

The phase of the composite dielectric may be different from the phases of the bulk dielectric and the ceramic nanosheet.

The composite dielectric may include multiple phases.

The phase of the ceramic nanosheet may be represented by any one of the following formulas 1 to 3.

[Formula 1]

X _m [A _(n-1) M _n O _(3n+1) ]

[Formula 2]

X _r [A _p M _(p-1) O _3p ]

[Formula 3]

X _r [M _p O _(2p+1) ]

In Formulas 1 to 3,

X is H, an alkali metal, a cation, a cationic compound, or a combination thereof,

A is at least one selected from Ca, Na, Ta, Bi, Ba and Sr,

M is different from A and is at least one selected from W, Mo, Cr, Ta, Nb, V, Zr, Hf, Pb, Sn, La and Ti,

0≤m≤2, 0≤r≤2, n≥1 and p≥1.

The phase of the composite dielectric can be expressed by the following formula (4).

[Formula 4]

Ba _a Ti _b A _c M _d Q _e O _f

In Formula 4 above,

A is at least one selected from Ca, Na, Ta, Bi, Ba and Sr,

M is different from A and is at least one selected from W, Mo, Cr, Ta, Nb, V, Zr, Hf, Pb, Sn, La and Ti,

Q is at least one selected from Si, Mn, Al, Fe, Zn, Ga, Dy and In,

0<a≤4, 0<b≤4, 0≤c≤8, 0<d≤8, 0≤e≤0.5 and 0<f≤30.

The ceramic nanosheet is a dielectric of Aurivilius phase, Ruddlesden-Popper phase, Dion-Jacobson phase, and Titano-Niobate phase. It may be a peeled structure.

The ceramic nanosheets include Ca ₂ Nb ₃ O ₁₀ , Ca ₂ NaNb ₄ O ₁₃ , Ca ₂ Na ₂ Nb ₅ O ₁₆ , Sr ₂ Nb ₃ O ₁₀ , SrBi ₄ Ti ₄ O ₁₅ , Ti ₂ NbO ₇ , LaNb ₂ O ₇ or a combination thereof.

The ceramic dielectric may include a plurality of semiconducting grains including the bulk dielectric, and an insulating grain boundary located between the adjacent semiconducting grains and including the ceramic nanosheet.

The composite dielectric may be included in at least one of the semiconducting grains and the insulating grain boundaries.

The ceramic dielectric may have higher dielectric constant and resistivity than the bulk dielectric.

The dielectric constant of the ceramic dielectric may be about two times higher than the dielectric constant of the bulk dielectric.

The ceramic dielectric may satisfy at least one of a dielectric constant of about 9,000 or more and a specific resistance of about 1x10 ⁹ Ω·cm or more at room temperature.

According to another embodiment, it includes a plurality of crystal grains, and grain boundaries filled between adjacent grains, and at least one of the grains and the grain boundaries is barium (Ba); Titanium (Ti); at least one selected from calcium (Ca), sodium (Na), tantalum (Ta), bismuth (Bi), barium (Ba), and strontium (Sr); and tungsten (W), molybdenum (Mo), chromium (Cr), tantalum (Ta), niobium (Nb), vanadium (V), zirconium (Zr), hafnium (Hf), lead (Pb), and tin (Sn). A ceramic dielectric comprising a composite dielectric containing at least one selected from lanthanum (La) and titanium (Ti) is provided.

The crystal grains may include a bulk dielectric containing barium (Ba) and titanium (Ti).

The grain boundaries may include ceramic nanosheets.

The ceramic nanosheets include Ca ₂ Nb ₃ O ₁₀ , Ca ₂ NaNb ₄ O ₁₃ , Ca ₂ Na ₂ Nb ₅ O ₁₆ , Sr ₂ Nb ₃ O ₁₀ , SrBi ₄ Ti ₄ O ₁₅ , Ti ₂ NbO ₇ , LaNb ₂ O ₇ or a combination thereof.

The composite dielectric may further include at least one selected from Si, Mn, Al, Fe, Zn, Ga, Dy, and In.

According to another embodiment, obtaining a bulk dielectric by heat treating a metal precursor including a barium precursor and a titanium precursor, preparing a ceramic nanosheet by exfoliating layered ceramic powder, and forming the ceramic nanosheet on the surface of the bulk dielectric. It provides a method of manufacturing a ceramic dielectric, including the step of coating, and sintering the ceramic nanosheet-coated bulk dielectric to obtain a ceramic dielectric including a composite dielectric of the bulk dielectric and the ceramic nanosheet.

The step of sintering the ceramic nanosheet-coated bulk dielectric may include a first heat treatment at about 1100 degrees to 1400 degrees, and a second heat treatment at about 600 degrees to 800 degrees.

The primary heat treatment may be performed in a reducing atmosphere, and the secondary heat treatment may be performed in an oxidizing atmosphere.

The manufacturing method further includes adding one or more oxides containing at least one selected from Si, Mn, Al, Fe, Zn, Ga, Dy, and In before sintering the ceramic nanosheet-coated bulk dielectric. It can be included.

The ceramic nanosheets include Ca ₂ Nb ₃ O ₁₀ , Ca ₂ NaNb ₄ O ₁₃ , Ca ₂ Na ₂ Nb ₅ O ₁₆ , Sr ₂ Nb ₃ O ₁₀ , SrBi ₄ Ti ₄ O ₁₅ , Ti ₂ NbO ₇ , LaNb ₂ O ₇ or a combination thereof.

The ceramic nanosheet may be included in an amount of about 1 to 15 parts by weight based on 100 parts by weight of the bulk dielectric.

According to another embodiment, a ceramic electronic component is provided, including a pair of electrodes facing each other, and a ceramic dielectric layer positioned between the pair of electrodes, wherein the ceramic dielectric layer includes the ceramic dielectric.

The ceramic electronic component may be a multilayer ceramic capacitor in which a plurality of unit capacitors including the pair of electrodes and the ceramic dielectric layer are stacked.

According to another embodiment, an electronic device including the ceramic electronic component is provided.

High dielectric constant and high resistivity of ceramic electronic components can be achieved simultaneously.

1 is a schematic diagram showing a portion of a ceramic dielectric according to an example;
2 is a schematic diagram showing a ceramic electronic component according to one implementation;
3 is a perspective view schematically showing a ceramic electronic component according to another embodiment;
Figure 4 is a cross-sectional view of the ceramic electronic component of Figure 3 taken in the direction A-A';
Figure 5 is an SEM photograph of the fracture surface of the ceramic dielectric obtained in Preparation Example 1;
Figure 6 shows the results of elemental analysis of the grain portion of the ceramic dielectric obtained in Preparation Example 1;
Figure 7 is an X-ray diffraction (XRD) graph of the ceramic dielectric obtained in Preparation Example 1;
Figure 8 is a transmission electron microscope (TEM) photograph of the ceramic dielectric obtained in Preparation Example 1.

Hereinafter, implementation examples will be described in detail so that those skilled in the art can easily implement them. However, the scope of rights may be implemented in several different forms and is not limited to the implementation examples described herein.

In the drawing, the thickness is enlarged to clearly express various layers and areas. Throughout the specification, similar parts are given the same reference numerals. When a part of a layer, membrane, region, plate, etc. is said to be “on” another part, this includes not only cases where it is “directly above” the other part, but also cases where there is another part in between. Conversely, when a part is said to be “right on top” of another part, it means that there is no other part in between.

Hereinafter, a ceramic dielectric according to an embodiment will be described.

A ceramic dielectric according to one embodiment includes a bulk dielectric; ceramic nanosheets; and composite dielectrics of bulk dielectrics and ceramic nanosheets.

The bulk dielectric may be, for example, a metal oxide with a three-dimensional structure and may have a dielectric constant of about 100 or more. As an example, the dielectric constant of the bulk dielectric may be about 100 to 10,000, about 150 to 5000, or about 200 to 1000. The bulk dielectric may be a metal oxide, including barium (Ba) and titanium (Ti), such as BaTiO ₃ or Ba _{0 . 5Sr 0 .} It may be ₅ TiO ₃ but is not limited thereto. The bulk dielectric may have a certain crystal structure, for example, a perovskite structure.

The ceramic nanosheet may be, for example, a metal oxide with a two-dimensional structure or, for example, an exfoliated nanostructure obtained from bulk ceramic powder with a layered structure. Ceramic nanosheets may be, for example, insulating metal oxides. As an example, the ceramic nanosheet may have an Aurivilius phase, a Ruddlesden-Popper phase, a Dion-Jacobson phase, or a Titano-Niobate phase. It may be a dielectric exfoliation structure.

As an example, the ceramic nanosheet may be made of a ceramic material having a dielectric constant of about 50 or more, for example, about 50 to 1000, about 100 to 500, about 150 to 250, for example. It may be an oxide containing one or two or more selected from Ca, Na, Ta, Bi, Ba, Sr, W, Mo, Cr, Nb, V, Zr, Hf, Pb, Sn, La, and Ti.

As an example, the phase of a ceramic nanosheet may be expressed in any one of the following formulas 1 to 3.

[Formula 1]

X _m [A _(n-1) M _n O _(3n+1) ]

[Formula 2]

X _r [A _p M _(p-1) O _3p ]

[Formula 3]

X _r [M _p O _(2p+1) ]

In Formulas 1 to 3,

X is H, an alkali metal, a cation, a cationic compound, or a combination thereof,

A is at least one selected from Ca, Na, Ta, Bi, Ba and Sr,

M is different from A and is at least one selected from W, Mo, Cr, Ta, Nb, V, Zr, Hf, Pb, Sn, La and Ti,

0≤m≤2, n≥1, 0≤r≤2 and p≥1.

As an example, ceramic nanosheets include Ca ₂ Nb ₃ O ₁₀ , Ca ₂ NaNb ₄ O ₁₃ , Ca ₂ Na ₂ Nb ₅ O ₁₆ , Sr ₂ Nb ₃ O ₁₀ , SrBi ₄ Ti ₄ O ₁₆ , Ti ₂ NbO ₇ , LaNb It may include ₂ O ₇ or a combination thereof, but is not limited thereto.

Each ceramic nanosheet may have a thin plate-like shape with a predetermined average lateral dimension. The size in the plane direction may be the width or length perpendicular to the thickness. The average surface size of the ceramic nanosheet may be, for example, about 0.1 μm to 30 μm, and within the above range, for example, may be about 0.2 μm to 20 μm, 0.3 μm to 15 μm, and about 0.5 μm to 10 μm. It can be. The average thickness of the ceramic nanosheets may be, for example, about 5 nm or less, and within the above range, such as about 3 nm or less, such as about 2 nm or less, such as about 1.5 nm or less, such as about 0.01 nm to 5 nm, such as about 0.01 nm to 3 nm, such as about It may be 0.01 nm to 2 nm or about 0.01 nm to 1.5 nm. The average surface size and average thickness of the ceramic nanosheets can be determined according to the synthesis and exfoliation conditions in the synthesis and exfoliation steps of the bulk ceramic powder.

The composite dielectric may include a sintered product of a bulk dielectric and ceramic nanosheets, and may include a plurality of phases each different from the phases of the bulk dielectric and ceramic nanosheets.

As an example, the composite dielectric may include barium (Ba), titanium (Ti), and a sintered product containing elements included in the dielectric of ceramic nanosheets, such as Ba; Ti; And it may be a sintered product containing one or two or more selected from Ca, Na, Ta, Bi, Ba, Sr, W, Mo, Cr, Nb, V, Zr, Hf, Pb, Sn, La, and Ti.

As an example, the phase of the composite dielectric may be determined depending on the components of the bulk dielectric and ceramic nanosheet, and may be expressed, for example, by the following formula (4).

[Formula 4]

Ba _a Ti _b A _c M _d Q _e O _f

In Formula 4 above,

A is at least one selected from Ca, Na, Ta, Bi, Ba and Sr,

M is different from A and is at least one selected from W, Mo, Cr, Ta, Nb, V, Zr, Hf, Pb, Sn, La and Ti,

Q is at least one selected from Si, Mn, Al, Fe, Zn, Ga, Dy and In,

0<a≤4, 0<b≤4, 0≤c≤8, 0<d≤8, 0≤e≤0.5 and 0<f≤30.

1 is a schematic diagram showing a portion of a ceramic dielectric according to an example.

Referring to FIG. 1, the ceramic dielectric 10 according to one embodiment includes a plurality of grains 10a and a grain boundary 10b located between adjacent grains 10a.

The grains 10a may include a bulk dielectric having the three-dimensional structure described above and may include, for example, barium (Ba) and titanium (Ti), such as BaTiO ₃ or Ba _{0 . 5Sr 0 .} It may include ₅ TiO ₃ but is not limited thereto. The bulk dielectric within the crystal grains 10a may have oxygen vacancies in its crystal structure and thus may exhibit semiconductor properties.

The particle size of the crystal grain 10a may vary within the range of about 0.001 μm to 10 μm, such as about 0.001 μm to 8 μm, such as about 0.01 μm to 7 μm, such as about 0.01 μm to 6 μm, such as about 0.01 μm. to 5 μm, such as about 0.01 μm to 4 μm, such as about 0.01 μm to 3 μm.

The average particle diameter of the crystal grains 10a is, for example, about 2.0 μm or less, about 1.8 μm or less, about 1.7 μm or less, about 1.5 μm or less, such as about 1.4 μm or less, such as about 1.3 μm or less, such as about 1.2 μm or less, such as about 1.1 μm or less. It may be ㎛ or less, such as about 1.0 ㎛ or less, such as about 900 nm or less, such as about 800 nm or less, such as about 700 nm or less, such as about 600 nm or less, such as about 500 nm or less, such as about 300 nm or less, such as about 50 nm or more, such as about 60 nm or less. , for example, about 70 nm or more, for example, about 80 nm or more, for example, about 90 nm or more, for example, about 100 nm or more, but is not limited thereto.

The grain boundary 10b is located between adjacent grains 10a within the ceramic dielectric 10 and may have, for example, a continuously connected structure. The grain boundary 10b may have a width thinner than the particle diameter of the crystal grain 10a, for example, may have a width within about 20%, for example, within about 15%, for example, within about 10% of the particle diameter of the crystal grain 10a, The range may have a width of about 0.1% to 20%, about 0.1% to 15%, or about 0.1% to 10%.

The grain boundary 10b may include the aforementioned ceramic nanosheets, such as calcium (Ca), sodium (Na), tantalum (Ta), bismuth (Bi), barium (Ba), strontium (Sr), and tungsten (W). ), molybdenum (Mo), chromium (Cr), niobium (Nb), vanadium (V), zirconium (Zr), hafnium (Hf), lead (Pb), tin (Sn), lanthanum (La), and titanium (Ti). ) and may include an oxide containing one or two or more selected from the group consisting of, for example, a dielectric represented by any one of the above-mentioned formulas 1 to 3, for example, Ca ₂ Nb ₃ O ₁₀ , Ca ₂ NaNb ₄ O ₁₃ , Ca ₂ Na ₂ Nb ₅ O ₁₆ , Sr ₂ Nb ₃ O ₁₀ , SrBi ₄ Ti ₄ O ₁₅ , Ti ₂ NbO ₇ , LaNb ₂ O ₇ or a combination thereof. Ceramic nanosheets can fill the space between adjacent crystal grains 10a. The ceramic nanosheet described above may be an insulating metal oxide, and accordingly, the grain boundary 10b may be an insulating grain boundary.

At least one of the grains 10a and the grain boundaries 10b may include the above-described composite dielectric. The composite dielectric may include a sinter of a bulk dielectric and ceramic nanosheets, such as barium (Ba); Titanium (Ti); and calcium (Ca), sodium (Na), tantalum (Ta), bismuth (Bi), barium (Ba), strontium (Sr), tungsten (W), molybdenum (Mo), chromium (Cr), and niobium (Nb). , vanadium (V), zirconium (Zr), hafnium (Hf), lead (Pb), tin (Sn), lanthanum (La), and titanium (Ti). For example, the composite dielectric includes barium (Ba); Titanium (Ti); at least one selected from calcium (Ca), sodium (Na), tantalum (Ta), bismuth (Bi), barium (Ba), and strontium (Sr); and tungsten (W), molybdenum (Mo), chromium (Cr), tantalum (Ta), niobium (Nb), vanadium (V), zirconium (Zr), hafnium (Hf), lead (Pb), and tin (Sn). , lanthanum (La), and titanium (Ti). For example, the complex dielectric may be expressed as Formula 4 above. The composite dielectric further includes at least one selected from, for example, silicon (Si), manganese (Mn), aluminum (Al), iron (Fe), zinc (Zn), gallium (Ga), dysprosium (Dy), and indium (In). can do.

As an example, the complex dielectric may be present in the crystal grain 10a.

As an example, the composite dielectric may exist at the grain boundary 10b.

As an example, the composite dielectric may exist in the grains 10a and grain boundaries 10b.

In this way, the ceramic dielectric 10 can secure high dielectric constant and resistivity by including thin grain boundaries 10b with insulating properties between the crystal grains 10a with semiconductor properties and adjacent crystal grains 10a.

As an example, the ceramic dielectric 10 may have a higher dielectric constant and resistivity than the bulk dielectric included in the crystal grains 10a. For example, the dielectric constant of the ceramic dielectric 10 may be about 2 times higher than the dielectric constant of the bulk dielectric included in the crystal grains 10a. It can be more than twice as high.

As an example, the ceramic dielectric 10 may satisfy at least one of a dielectric constant of about 9,000 or more and a resistivity of about 1x10 ⁹ Ω·cm or more. For example, the dielectric constant and the resistivity may be satisfied simultaneously. Within the above range, the ceramic dielectric 10 may satisfy, for example, a dielectric constant of about 10,000 or more and/or a resistivity of about 1x10 ¹⁰ Ω·cm or more, and, for example, a dielectric constant of about 11,000 or more and/or a resistivity of about 1x10 ¹¹ Ω·cm or more. and, for example, may satisfy a dielectric constant of about 12,000 or more and/or a resistivity of about 1x10 ¹¹ Ω·cm or more.

Hereinafter, a manufacturing method of a ceramic dielectric according to an embodiment will be described.

A method of manufacturing a ceramic dielectric according to an embodiment includes preparing a bulk dielectric, preparing a ceramic nanosheet, coating the ceramic nanosheet on the surface of the bulk dielectric, and sintering the ceramic nanosheet-coated bulk dielectric. It includes obtaining a composite dielectric of bulk dielectric and ceramic nanosheets.

Bulk dielectrics can be obtained by heat treating metal precursors, including, for example, barium precursors and titanium precursors. Here the barium precursor may be, for example, barium oxide, barium carbonate and/or barium hydroxide, for example BaCO ₃ , BaO and/or Ba(OH) ₂ , and the titanium precursor may be, for example, titanium oxide, titanium carbonate, titanium hydroxide or titanium. It may be an acetate, such as TiO ₂ and/or Ti(OH) ₄ .

The barium precursor and the titanium precursor may be included at a molar ratio of, for example, about 0.8:1.2 to 1.2:0.8, within the above range, for example, at a molar ratio of about 0.9:1.1 to 1.1:0.9, and within the above range, for example, about 1:1. It can be included in a molar ratio of.

Heat treatment may be performed in air, for example, at a temperature of about 700°C to 1200°C, such as about 600°C to 1000°C, or about 600°C to 800°C.

Ceramic nanosheets can be obtained, for example, from layered ceramic materials, for example, by heat treating a mixture containing a transition metal oxide and an alkali metal compound and/or an alkaline earth metal compound.

Transition metal oxides include, for example, Nb, Sr, Bi, Ti, Re, V, Os, Ru, Ta, Ir, W, Ga, Mo, In, Cr, Rh, Mn, Co, Fe or combinations thereof. It may be selected from, for example, Nb ₂ O ₅ , etc., but is not limited thereto. The alkali metal compound and/or alkaline earth metal oxide may be selected from compounds containing Ca, K, or a combination thereof, for example, CaCO ₃ , K ₂ CO ₃ , etc., but is not limited thereto.

The mixing ratio of the transition metal oxide and the alkali metal compound and/or the alkaline earth metal compound may be appropriately selected in consideration of the composition of the ceramic material to be manufactured, for example, 0.1 mole to 0.1 mole of the alkali metal compound and/or alkaline earth metal compound per mole of the transition metal oxide. 1 mole can be mixed, but is not limited to this. Heat treatment may be performed for about 10 to 50 hours at about 750 to 1500 degrees in an atmosphere such as an air atmosphere, a nitrogen atmosphere, an argon atmosphere or a vacuum, but is not limited thereto.

Layered ceramic materials can be obtained as layered ceramic powder by pulverizing them. Layered ceramic powder can be exfoliated in various ways, for example, through sequential ion exchange and intercalation reaction of protic acid and organic cation using osmotic pressure phenomenon.

As an example, the layered ceramic powder may be acid-exchanged with an acidic solution such as hydrochloric acid or sulfuric acid to obtain a layered proton exchanged ceramic powder in which at least a portion of the alkali metal is exchanged with protons (H ⁺ ). The concentration of the acidic solution, treatment temperature, treatment time, etc. may be appropriately selected and are not particularly limited.

The obtained layered proton exchange ceramic powder is then subjected to intercalation treatment to obtain intercalated layered ceramic powder. Intercalation may be performed, for example, using a C1 to C20 alkylammonium salt compound as an intercalant, but is not limited thereto. Alkylammonium salt compounds include, for example, tetramethylammonium compounds such as tetramethylammonium hydroxide, tetraethyl ammonium compounds such as tetraethylammonium hydroxide, tetrapropylammonium compounds such as tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide. It may be a tetrabutylammonium compound such as and/or a benzylalkylammonium compound such as benzylmethylammonium hydroxide, but is not limited thereto.

The alkylammonium salt compound may be provided in the form of an aqueous solution, and the concentration of the aqueous alkylammonium salt solution may be about 0.01 to 20 mol% based on the protons of the layered proton exchange ceramic powder, but is not limited thereto. The temperature and time of the intercalation treatment are not particularly limited and, for example, may be performed at about 25 degrees to 80 degrees for about 1 to 5 days, but are not limited thereto. The intercalant is inserted between layers of layered proton exchange ceramic powder, allowing them to be easily separated into ceramic nanosheets. For effective exfoliation, centrifugation, ultrasound, or a combination thereof can be performed.

Ceramic nanosheets exfoliated from layered ceramic powder may be single-crystal ceramic nanosheets and may be stably dispersed in a solvent and exist in a colloidal form. The solvent may be, for example, a high dielectric constant solvent, for example, water or a polar solvent, and may be, for example, water, alcohol, acetonitrile, dimethyl sulfoxide, dimethylformamide, propylene carbonate, or a combination thereof, but is not limited thereto. .

The ceramic nanosheets can be coated on the surface of the bulk dielectric by mixing the bulk dielectric obtained above with the ceramic nanosheet. At this time, the ceramic nanosheet may be included in a smaller amount than the bulk dielectric, for example, the ceramic nanosheet may be included in an amount of about 0.1 to 20 parts by weight based on 100 parts by weight of the bulk dielectric, and within the above range, it may be included in an amount of about 0.5 to 20 parts by weight, about 1 to 20 parts by weight. It may be included in about 1 to 15 parts by weight.

When mixing the bulk dielectric and ceramic nanosheets, a sintering agent may be further included. The sintering additive may be, for example, an oxide or glass compound containing Si, Mn, Al, Fe, Zn, Ga, Dy and/or In, but is not limited thereto. The sintering additive may be SiO ₂ , for example. The sintering additive may be provided in an amount of about 0.1 to 5 moles per 100 moles of the bulk dielectric, and within the above range, for example, about 0.3 to 2 moles, or about 0.1 to 1.5 moles.

The step of sintering the ceramic nanosheet-coated bulk dielectric may be performed continuously in different atmospheres and/or temperatures, and may include, for example, a primary heat treatment in a reducing atmosphere and a secondary heat treatment in an oxidizing atmosphere. . Here, the reducing atmosphere may be a strong reducing atmosphere and the oxidizing atmosphere may be a weak oxidizing atmosphere.

The primary heat treatment in a strong reducing atmosphere may be at a high temperature of 1000° C. or higher in a dry gas atmosphere, and the secondary heat treatment in a weak oxidizing atmosphere may be at a lower temperature than the strong reducing atmosphere, for example in air and/or wet gas atmosphere. For example, the primary heat treatment in a reducing atmosphere may be at a high temperature of 1000°C or higher in a dry H ₂ gas or dry N ₂ /H ₂ mixed gas atmosphere, and the secondary heat treatment in a weak oxidizing atmosphere may be at a high temperature of 1000°C or higher in a weak oxidizing atmosphere, for example, in air and/or wet N ₂ atmosphere. The temperature may be lower than that of the reducing atmosphere. For example, the strong reducing atmosphere is 100% dry H ₂ gas or the volume ratio of N ₂ :H ₂ is, for example, about 1:99 to 99:1, about 10:90 to 90:10, about 20:80 to 80:20, about 30. :70 to 70:30, about 40:60 to 60:40, about 50:50, may be a dry N ₂ /H ₂ mixed gas atmosphere, and the slightly oxidizing atmosphere may be 100% wet N ₂ gas or N ₂ :H ₂ The volume ratio is, for example, about 1:99 to 99:1, about 10:90 to 90:10, about 20:80 to 80:20, about 30:70 to 70:30, about 40:60 to 60:40, about It may be a 50:50 wet N ₂ /H ₂ mixed gas atmosphere. The first heat treatment and the second heat treatment can each be independently performed for about 1 hour to 6 hours, for example, about 2 hours to 4 hours.

As an example, the strong reducing atmosphere may be, for example, an N ₂ /H ₂ mixed gas atmosphere and a temperature of about 1100°C to 1400°C, and the weak oxidizing atmosphere may be, for example, air and/or a wet N ₂ atmosphere and a temperature of about 600°C to 800°C. It could be temperature. Within the above range, a strong reducing atmosphere may have a temperature of about 1200 to 1300°C, and a weak oxidizing atmosphere may have a temperature of, for example, about 650 to 800°C. The first heat treatment and the second heat treatment can each be independently performed for about 1 hour to 6 hours, for example, about 2 hours to 4 hours. The heat treatment temperature and time in a strong reducing atmosphere and a weak oxidizing atmosphere can be variously adjusted depending on the desired dielectric constant and resistivity.

In this way, by continuously heat treating in a weak oxidizing atmosphere after heat treatment in a strong reducing atmosphere, sufficient oxygen vacancies can be secured by preventing or reducing the disappearance of oxygen vacancies in the crystal grains 10a, and thus a high dielectric constant ceramic dielectric containing semiconducting crystal grains ( 10) can be obtained.

The obtained ceramic dielectric 10 may be filled between a plurality of crystal grains 10a formed from a bulk dielectric and adjacent crystal grains 10a and may include a grain boundary 10b formed from a ceramic nanosheet, and the crystal grains 10a and the crystal grain boundary 10b ), at least one of which may include a composite dielectric of a bulk dielectric and a ceramic nanosheet.

Hereinafter, a ceramic electronic component of one embodiment will be described.

Figure 2 is a schematic diagram showing a ceramic electronic component according to one implementation.

Figure 2 shows a capacitor 50, which is an example of a ceramic electronic component.

Referring to FIG. 2, the capacitor 50 according to one embodiment includes a pair of electrodes 51 and 52 facing each other and a ceramic dielectric 10.

A pair of electrodes 51 and 52 includes a conductor such as a metal, such as nickel (Ni), gold (Au), platinum (Pt), palladium (Pd), copper (Cu), silver (Ag), It may include tin (Sn), alloys thereof, or combinations thereof, but is not limited thereto. The pair of electrodes 51 and 52 may be, for example, a metal plate, for example, a conductive layer formed on a substrate (not shown), or, for example, a metal plate plated on a substrate (not shown). Here, the substrate may be, for example, a glass substrate, a semiconductor substrate, a polymer substrate, or a combination thereof.

The ceramic dielectric 10 is as described above.

FIG. 3 is a perspective view schematically showing a ceramic electronic component according to another embodiment, and FIG. 4 is a cross-sectional view of the ceramic electronic component of FIG. 3 taken along the A-A′ direction.

The ceramic electronic component according to this embodiment is a multilayer ceramic capacitor (MLCC) 100 having a structure in which a plurality of capacitors of FIG. 2 are stacked using the capacitor of FIG. 2 as a unit capacitor.

Referring to FIGS. 3 and 4 , the multilayer ceramic capacitor 100 includes a capacitor body 61 and external electrodes 62 and 63. The capacitor body 61 has a structure in which a plurality of capacitors 50 shown in FIG. 4 are stacked, and each capacitor includes electrodes (internal electrodes) 51 and 52 and a ceramic dielectric 10, as described above. . The specific description is as described above.

In the above, capacitors and multilayer ceramic capacitors are described as examples of ceramic electronic components, but the application is not limited thereto and can be applied to all electronic components that use ceramics, such as inductors, piezoelectric elements, varistors, or thermistors.

Ceramic electronic components such as the above-described capacitors and multilayer ceramic capacitors may be included in various electronic devices, such as video devices such as liquid crystal displays, computers, and mobile phones.

The above-described implementation example will be described in more detail through examples below. However, the following examples are for illustrative purposes only and do not limit the scope of rights.

Synthesis example

Synthesis example 1: Synthesis of barium titanium oxide

Add 1 mol of BaCO ₃ , 1 mol of TiO ₂ and 0.0025 mol of dysprosium (Dy) with ethanol and mix for 24 hours using a ball mill. Next, the mixed powder is dried while mixing in a beaker using a magnetic bar and hot plate. The dried powder is dried in an oven at 80°C for an additional day. The mixture is then calcined in air at 1000°C for 4 hours to prepare barium titanium oxide.

Synthesis example 2: Ceramic Nanosheet (Ca ₂ Na ₂ Nb ₅ O ₁₆ )of synthesis

Prepare K ₂ CO ₃ , CaCO ₃ , Nb ₂ O ₅ and NaO at a molar ratio of 1.1:2:5:2. Next, ethanol is added to the powder and mixed using a ball mill for 24 hours. Next, the mixed powder is dried while mixing in a beaker using a magnetic bar and hot plate. To ensure sufficient drying, additionally dry in an oven at 100 degrees for 1 day. Next, calcining is performed at 1200 degrees for 10 hours in an air atmosphere to prepare the KCa ₂ Na ₂ Nb ₅ O ₁₆ mother phase.

Then KCa ₂ Na ₂ Nb ₅ O ₁₆ The mother phase is stirred in HCl solution or HNO ₃ solution and then filtered to obtain HCa ₂ Na ₂ Nb ₅ O ₁₆ powder. The obtained HCa ₂ Na ₂ Nb ₅ O ₁₆ powder is added to tetrabutylammonium hydroxide solution (TBAOH), stirred, centrifuged, and separated into two-dimensional ceramic nanosheets. At this time, HCa ₂ Nb ₃ O ₁₀ ·1.5H ₂ O and TBAOH are mixed in a ratio of 1:1. Exfoliation is carried out by mechanical shaking at 150 rpm for 7 days at room temperature. Next, after removing the sediment at the bottom of the beaker, centrifuge for 30 minutes at 2,000 rpm using a centrifuge. Only the supernatant (2/3) is used and the settled residue is discarded. Then, the centrifuged supernatant is dialyzed using a membrane to remove the tetrabutylammonium aqueous solution to prepare a nanosheet solution containing Ca ₂ Na ₂ Nb ₅ O ₁₆ ceramic nanosheets. Ca ₂ Na ₂ Nb ₅ O ₁₆ ceramic nanosheets have an average thickness of about 2.5 nm and an average surface size of about 500 nm.

Manufacturing example

Manufacturing example One

Prepare 100 parts by weight of the barium titanium oxide obtained in Synthesis Example 1 and 1 part by weight of the Ca ₂ Na ₂ Nb ₅ O ₁₆ ceramic nanosheet obtained in Synthesis Example 2.

First, the barium titanium oxide obtained in Synthesis Example 1 is immersed in 1 part by weight aqueous solution of polyethyleneimine, a cationic compound, and then surface treated through ultrasonic treatment. The supernatant solution is then removed using a centrifuge. Subsequently, Ca ₂ Na ₂ Nb ₅ O ₁₆ obtained in Synthesis Example 2 After immersing the surface-treated barium titanium oxide in the nanosheet solution, ultrasonic treatment is performed to coat the surface of the barium titanium oxide with Ca ₂ Na ₂ Nb ₅ O ₁₆ ceramic nanosheets. The supernatant is then removed through centrifugation. Next, 1 mol% of Mn ₂ O ₃ and 1 mol% of SiO ₂ were added and mixed to the barium titanium oxide coated with Ca ₂ Na ₂ Nb ₅ O ₁₆ ceramic nanosheets, and then incubated at about 1250°C for 2 hours in a wet H ₂ atmosphere. A ceramic dielectric is manufactured by reduction sintering and reoxidation at 700°C for 2 hours in a wet N ₂ atmosphere.

Manufacturing example 2

A ceramic dielectric was manufactured in the same manner as Preparation Example 1, except that 4 parts by weight of Ca ₂ Na ₂ Nb ₅ O ₁₆ ceramic nanosheets were included.

Manufacturing example 3

A ceramic dielectric was manufactured in the same manner as Preparation Example 1, except that 7 parts by weight of Ca ₂ Na ₂ Nb ₅ O ₁₆ ceramic nanosheets were included.

Manufacturing example 4

A ceramic dielectric was manufactured in the same manner as Preparation Example 1, except that 15 parts by weight of Ca ₂ Na ₂ Nb ₅ O ₁₆ ceramic nanosheets were included.

Comparative manufacturing example One

A ceramic dielectric was manufactured in the same manner as Preparation Example 1, except that the Ca ₂ Na ₂ Nb ₅ O ₁₆ ceramic nanosheet was not included.

Evaluation I

The fractured surface of the ceramic dielectric obtained in Preparation Example 1 was observed using a scanning electron microscope (SEM).

Figure 5 is an SEM photograph of the fracture surface of the ceramic dielectric obtained in Preparation Example 1, and Figure 6 is the result of elemental analysis of the grain portion of the ceramic dielectric obtained in Preparation Example 1.

Referring to FIG. 5, it can be seen that the ceramic dielectric has a structure having a plurality of crystal grains and grain boundaries located between them.

Referring to Figure 6, it can be seen that calcium (Ca), sodium (Na), and niobium (Nb), in addition to barium (Ba) and titanium (Ti), were detected in the crystal grain portion of the ceramic dielectric, and from this, barium was detected in the ceramic dielectric. It can be confirmed that a composite dielectric of titanium oxide (bulk dielectric) and Ca ₂ Na ₂ Nb ₅ O ₁₆ ceramic nanosheets exists.

Evaluation II

Figure 7 is an X-ray diffraction (XRD) graph of the ceramic dielectric obtained in Preparation Example 1.

Referring to FIG. 7, it can be seen that the ceramic dielectric includes a phase represented by CaBa ₂ TiNb ₄ O ₁₅ and a plurality of other new phases, and the new phases include barium titanium oxide obtained in Synthesis Example 1 and Synthesis Example 2. It can be seen that each is different from the obtained Ca ₂ Na ₂ Nb ₅ O ₁₆ ceramic nanosheet.

Evaluation III

Figure 8 is a transmission electron microscope (TEM) photograph of the ceramic dielectric obtained in Preparation Example 1.

Referring to FIG. 8, it can be seen that Ca, Nb, etc., which are components of the Ca ₂ Na ₂ Nb ₅ O ₁₆ ceramic nanosheet, coexist in the phase of barium titanium oxide, and from this, the ceramic dielectric is a new phase different from barium titanium oxide. You can confirm that it includes.

Example

Example One

A capacitor is manufactured by applying In-Ga to both sides of the ceramic dielectric obtained in Preparation Example 1 to form electrodes.

Example 2

A capacitor is manufactured by applying In-Ga to both sides of the ceramic dielectric obtained in Preparation Example 2 to form electrodes.

Example 3

A capacitor was manufactured by applying In-Ga to both sides of the ceramic dielectric obtained in Preparation Example 3 to form electrodes.

Example 4

A capacitor was manufactured by applying In-Ga to both sides of the ceramic dielectric obtained in Preparation Example 4 to form electrodes.

Comparative example One

A capacitor was manufactured by applying In-Ga to both sides of the ceramic dielectric obtained in Comparative Preparation Example 1 to form electrodes.

Evaluation IV

The dielectric constant, dielectric loss, and specific resistance of the capacitors according to Examples 1 to 4 and Comparative Example 1 were evaluated.

Permittivity and dielectric loss are evaluated using a 4284A LCR meter, and resistivity is evaluated using a Keithley 2400.

The results are shown in Table 1.

Dielectric constant (1kHz) Dielectric loss (tanδ, %) Specific resistance (Ω·cm) Example 1 11,000 7.8 1x10 ⁹ Example 2 13,000 7.1 1x10 ¹¹ Example 3 18,000 6.4 3x10 ¹¹ Example 4 9,000 6.8 1x10 ¹⁰ Comparative Example 1 6,000~7,000 5.0 1x10 ⁶

Referring to Table 1, it can be seen that the capacitors according to Examples 1 to 4 satisfy a dielectric constant of 9,000 or more, a dielectric loss of 8% or less, and a resistivity of 1x10 ⁹ Ω·cm or more, and simultaneously satisfy high dielectric constant and high resistivity.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements can be made by those skilled in the art using the basic concept of the present invention as defined in the following claims. It falls within the scope of invention rights.

10: Ceramic dielectric
10a: grain 10b: grain boundary
51, 52: electrode 61: capacitor body
62, 63: external electrode 100: multilayer ceramic capacitor

Claims (26)

Bulk dielectrics containing barium (Ba) and titanium (Ti);
ceramic nanosheets, and
Composite dielectric of the bulk dielectric and the ceramic nanosheet
A ceramic dielectric containing.
In paragraph 1:
A ceramic dielectric wherein the phase of the composite dielectric is different from the phases of the bulk dielectric and the ceramic nanosheet.
In paragraph 1:
The composite dielectric is a ceramic dielectric including a plurality of phases.
In paragraph 1:
The phase of the ceramic nanosheet is a ceramic dielectric represented by any one of the following formulas 1 to 3:
[Formula 1]
X _m [A _(n-1) M _n O _(3n+1) ]
[Formula 2]
X _r [A _p M _(p-1) O _3p ]
[Formula 3]
X _r [M _p O _(2p+1) ]
In Formulas 1 to 3,
X is H, an alkali metal, a cation, a cationic compound, or a combination thereof,
A is at least one selected from Ca, Na, Ta, Bi, Ba and Sr,
M is different from A and is at least one selected from W, Mo, Cr, Ta, Nb, V, Zr, Hf, Pb, Sn, La and Ti,
0≤m≤2, 0≤r≤2, n≥1 and p≥1.
In paragraph 1:
The phase of the composite dielectric is a ceramic dielectric represented by the following formula 4:
[Formula 4]
Ba _a Ti _b A _c M _d Q _e O _f
In Formula 4 above,
A is at least one selected from Ca, Na, Ta, Bi, Ba and Sr,
M is different from A and is at least one selected from W, Mo, Cr, Ta, Nb, V, Zr, Hf, Pb, Sn, La and Ti,
Q is at least one selected from Si, Mn, Al, Fe, Zn, Ga, Dy and In,
0<a≤4, 0<b≤4, 0≤c≤8, 0<d≤8, 0≤e≤0.5 and 0<f≤30.
In paragraph 1:
The ceramic nanosheet is a dielectric of Aurivilius phase, Ruddlesden-Popper phase, Dion-Jacobson phase, or Titano-Niobate phase. Ceramic dielectric, which is a peel-off structure of.
In paragraph 1:
The ceramic nanosheets include Ca ₂ Nb ₃ O ₁₀ , Ca ₂ NaNb ₄ O ₁₃ , Ca ₂ Na ₂ Nb ₅ O ₁₆ , Sr ₂ Nb ₃ O ₁₀ , SrBi ₄ Ti ₄ O ₁₅ , Ti ₂ NbO ₇ , LaNb ₂ O ₇ or a ceramic dielectric comprising a combination thereof.
In paragraph 1:
A plurality of semiconducting crystal grains containing the bulk dielectric, and
Insulating grain boundaries located between the adjacent semiconducting grains and including the ceramic nanosheets
A ceramic dielectric containing.
In paragraph 8:
The composite dielectric is a ceramic dielectric included in at least one of the semiconducting grains and the insulating grain boundaries.
In paragraph 1:
The ceramic dielectric has a higher permittivity and resistivity than the bulk dielectric.
In paragraph 1:
A ceramic dielectric whose dielectric constant is more than two times higher than the dielectric constant of the bulk dielectric.
In paragraph 1:
A ceramic dielectric that satisfies at least one of a dielectric constant of 9,000 or more and a specific resistance of 1x10 ⁹ Ωㆍcm or more at room temperature.
Multiple grains, and
Grain boundaries filled between adjacent grains
Including,
At least one of the grains and the grain boundaries is
Barium (Ba); Titanium (Ti); at least one selected from calcium (Ca), sodium (Na), tantalum (Ta), bismuth (Bi), barium (Ba), and strontium (Sr); and tungsten (W), molybdenum (Mo), chromium (Cr), tantalum (Ta), niobium (Nb), vanadium (V), zirconium (Zr), hafnium (Hf), lead (Pb), and tin (Sn). , a composite dielectric containing at least one selected from lanthanum (La) and titanium (Ti)
A ceramic dielectric containing.
In paragraph 13:
The crystal grains are a ceramic dielectric including a bulk dielectric containing barium (Ba) and titanium (Ti).
In paragraph 13:
The grain boundary is a ceramic dielectric including ceramic nanosheets.
In paragraph 15:
The ceramic nanosheets include Ca ₂ Nb ₃ O ₁₀ , Ca ₂ NaNb ₄ O ₁₃ , Ca ₂ Na ₂ Nb ₅ O ₁₆ , Sr ₂ Nb ₃ O ₁₀ , SrBi ₄ Ti ₄ O ₁₅ , Ti ₂ NbO ₇ , LaNb ₂ O ₇ or a ceramic dielectric comprising a combination thereof.
In paragraph 13:
The composite dielectric further includes at least one selected from silicon (Si), manganese (Mn), aluminum (Al), iron (Fe), zinc (Zn), gallium (Ga), dysprosium (Dy), and indium (In). ceramic dielectric.
obtaining a bulk dielectric by heat treating metal precursors including a barium precursor and a titanium precursor;
Preparing ceramic nanosheets by exfoliating layered ceramic powder,
coating the ceramic nanosheet on the surface of the bulk dielectric, and
Sintering the ceramic nanosheet-coated bulk dielectric to obtain a ceramic dielectric including a composite dielectric of the bulk dielectric and the ceramic nanosheet.
A method of manufacturing a ceramic dielectric comprising.
In paragraph 18:
The step of sintering the ceramic nanosheet coated bulk dielectric is
First heat treatment at 1100 to 1400 degrees, and
Secondary heat treatment at 600 to 800 degrees
A method of manufacturing a ceramic dielectric comprising.
In paragraph 19:
The first heat treatment is performed in a reducing atmosphere,
The secondary heat treatment is performed in an oxidizing atmosphere.
Method for manufacturing ceramic dielectric.
In paragraph 18:
Before sintering the ceramic nanosheet coated bulk dielectric
A method of manufacturing a ceramic dielectric further comprising adding one or more oxides containing at least one selected from Si, Mn, Al, Fe, Zn, Ga, Dy, and In.
In paragraph 18:
The ceramic nanosheets include Ca ₂ Nb ₃ O ₁₀ , Ca ₂ NaNb ₄ O ₁₃ , Ca ₂ Na ₂ Nb ₅ O ₁₆ , Sr ₂ Nb ₃ O ₁₀ , SrBi ₄ Ti ₄ O ₁₅ , Ti ₂ NbO ₇ , LaNb ₂ O ₇ or a method of manufacturing a ceramic dielectric comprising a combination thereof.
In paragraph 18:
A method of manufacturing a ceramic dielectric, wherein the ceramic nanosheet includes 1 to 15 parts by weight based on 100 parts by weight of the bulk dielectric.
A pair of electrodes facing each other, and
Ceramic dielectric layer located between the pair of electrodes
Including,
The ceramic dielectric layer is a ceramic electronic component including the ceramic dielectric according to any one of claims 1 to 17.
In paragraph 24:
The ceramic electronic components are
A multilayer ceramic capacitor in which a plurality of unit capacitors including the pair of electrodes and the ceramic dielectric layer are stacked.
Ceramic electronic components.
An electronic device comprising a ceramic electronic component according to claim 24.

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