JPH08290964A - Dielectric composition, its production and its use - Google Patents

Abstract

PURPOSE: To obtain a dielectric composition capable of providing dense structure and excellent in insulating property by selecting a dielectric composition having a specific composition. CONSTITUTION: This dielectric composition has a composition expressed by the formula, s (AuCvRwOx)-(1-s) (AOy-bCOr-aGOz) [A is Ca, Sr, Ba, Pb, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or Y; C is Bi, Sc, Sb, Cr or Tl; R is Ti, Ta, Hf, W, Mo, Nb or Zr; G is B, As, Sb, Si, Ge, Te or P; 0.3<(s)<=0.95; 1/19<=(a)<=2.0; 0.5<=(b)/(a)<=7; (u), (v), (w) and (x) are each a real number determined so that total electron charge becomes O; when A is divalent, (y) is 1; when A is trivalent, (y) is 1.5; when C is trivalent, (r) is 1.5 and when C is quadrivalent, (r) is 2; when C is pentavalent, (r) is 2.5; when C is hexavalent, (r) is 3; when G is trivalent, (z) is 1.5; when G is quadrivalent, (z) is 2; when G is pentavalent, (z) is 2.5].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric composition, a method for producing the same, and uses thereof. The dielectric composition of the present invention is applied to thin film capacitors, capacitors for DRAM memory, ferroelectric memories, laminated capacitors, dielectric products such as dielectric pastes, actuators, resonators, filters, piezoelectric components such as ultrasonic motors, and the like. can do. In addition, the fine single crystal powder of the dielectric composition can be applied as a piezoelectric composite to piezoelectric components such as actuators and pressure-sensitive sensors, and to phosphor materials by doping rare earth ions.

[0002]

2. Description of the Related Art Conventionally, dielectric materials such as barium titanate and lead titanate have been used as porcelain capacitors and filters due to their dielectric and piezoelectric characteristics. Also,
In recent years, application to so-called ferroelectric memory, which uses polarization as a memory, has been actively studied.

In general, these porcelain capacitors are used in a laminated form in order to increase the capacity. In the method of manufacturing a multilayer capacitor, a dielectric powder having a particle size of 0.5 to 5 μm obtained by a solid phase reaction or a solution reaction is mixed with a binder or a solvent to manufacture a slurry, and the slurry is doctor blade method. Etc. to form a thin plate, and the thin plates are laminated in 10 to several tens layers, and then 1200 to 1300 ° C.
The process of baking is adopted.

However, in the case of such a method, the firing temperature is high at a temperature of 1300 ° C. or higher, and a relatively inexpensive metal having a low resistance such as silver or copper cannot be used as an electrode. Attempts have also been made to mix glass frit with dielectric powder in order to lower the firing temperature. Although it became possible to lower the firing temperature to about 1000 ° C by this method, the melting point of silver (96
It is high when viewed from 5 ° C.), and further, when a large amount of glass frit is added and the ratio of the dielectric material is decreased, the dielectric properties are deteriorated.

Further, since the dielectric powder, and particularly the glass frit, is manufactured by crushing, it is extremely difficult to make the particle size to be 1 μm or less, so it is difficult to achieve a dense green body structure, and the film is It was difficult to reduce the thickness. That is, when the thin film dielectric is formed by the doctor blade method using the dielectric powder obtained by the solid phase method or the liquid phase method, the dielectric powder is large, so that the film thickness of the dielectric should not be 20 μm or less. It was difficult.

By the way, the capacitance of the capacitor is C = (ε0 εrS / d) × n (where C is capacitance, S is area, d is distance between electrodes, ε
0 is the vacuum permittivity, εr is the relative permittivity, and n is the number of layers. ), There is a limit to the area and thickness in order to reduce the size and increase the capacity of the multilayer ceramic capacitor, so the number of layers should be increased. There is a limit to high capacity. One of the solutions is to thin the dielectric layer.

In the case of a multilayer capacitor, one layer is about 20
Although it is about 40 μm, if the thickness can be reduced to about 1 to 5 μm, a large capacity can be obtained and the size can be reduced. As a method of thinning, in addition to the doctor blade method and the printing method,
Vapor-phase methods such as sputtering, vacuum evaporation, and CVD, sol-gel methods, coating of organometallic compounds, methods of producing thin-film dielectrics by thermal decomposition, etc. are known, but they are thin. There are drawbacks such as easy short circuit and large leakage current. Also known is a method of using a ferroelectric crystallized glass to obtain a dense molded body.

Regarding these dielectric powders, generally, a solid phase reaction by firing powders of oxides, carbonates and the like at a high temperature, a coprecipitation method by a solution reaction in an aqueous solution, etc.
It is manufactured as a dielectric powder of 5 to 5 μm. In any of these reactions, the obtained powder was composed of secondary particles formed by agglomeration of primary particles, and there was a problem in composition uniformity and crystallinity. A hydrothermal synthesis method has been proposed to solve this problem, but the method requires high temperature and high pressure, and the cost is high due to equipment cost, productivity, and the like. Therefore, as another method, a method using crystallized glass has been proposed.

In the method using crystallized glass, the compound is first mixed in a composition capable of forming glass, and then 1400.
The glass is melted at a high temperature of about 0 ° C. and then rapidly cooled to obtain glass, which is then heat-treated at 600 to 800 ° C. to crystallize to obtain crystallized glass. According to this method, the size of the initial particles is not limited, so that it is possible to make the film thin, and because of the denseness, low dielectric loss and high withstand voltage can be realized. Moreover, a fine single crystal is obtained by melting and removing this glass component.

However, as is well known, the composition that can be vitrified is extremely limited. In particular, metals other than alkali metals, alkaline earth metals, and metals that form glass network forming oxides (oxides such as Si, B, P, Se, Te), metal oxides, specifically, for example, Ti, Z
It is known that r, Ta and the like act as a nucleating agent and promote crystallization when blended with glass. For this reason, the ratio of the high dielectric constant crystal phase that requires a large amount of these is 3
It is extremely difficult to increase it to more than 0%, which makes it impossible to obtain a high dielectric constant by this method.

[0011]

DISCLOSURE OF THE INVENTION The present invention provides the characteristics by increasing the proportion of the ferroelectric crystal phase,
The present invention relates to a dielectric composition which gives a denser structure at a lower temperature than that of a crystal phase alone and has a good insulating property, a method for producing the same, and a use thereof. In particular, it relates to a manufacturing method that can be synthesized at a lower temperature, a dielectric composition obtained by the manufacturing method, and its use.

[0012]

Means for Solving the Problems That is, the present invention is as follows. [1] General formula (1)

S (Au Cv Rw Ox)-(1-s) (AOy-bCOr-aGOz) (1) (wherein A is Ca, Sr, Ba, Pb, La, Ce, P
r, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
1 or 2 or more elements selected from o, Er, Tm, Yb, Lu and Y, C is 1 or 2 or more elements selected from Bi, Sc, Sb, Cr and Tl, R is Ti, Ta, H
One or more elements selected from f, W, Mo, Nb, and Zr, and G is one or more elements selected from B, As, Sb, Si, Ge, Te, and P. s, a and b represent real numbers, and 0.3 <s ≦ 0.95, 1/19 ≦
It is in the range of a ≦ 2 and 0.5 ≦ b / a ≦ 7. s represents the mole fraction of the crystal phase. u, v, w and x have zero total charge
Is a real number that is determined to be. y, r, and z represent oxygen numbers, y = 1 when A is divalent, y = 1.5 when A is trivalent, and r = 1.5 when C is trivalent, C
Is 4 when r is 2, r is 2.5 when C is 5,
When C is hexavalent, r = 3, and when G is trivalent, z =
1.5, z = 2 when G is tetravalent, z when G is pentavalent
= 2.5. ) The dielectric composition having a composition represented by:

[2] A compound of the element A, a compound of the element C, a compound of the element B and a compound of the element G, which are oxides or raw materials which can be converted into oxides, are converted into atoms, molecules or their compounds. Characterized in that they are aggregates and are mixed in the form of clusters, oligomers or fine particles whose size is less than 0.1 μm in diameter, and the mixture is heat-treated at a temperature at which it can be converted into an oxide. The method for producing a dielectric composition according to the above item [1].

[3] A method for producing a dielectric composition by applying a dielectric forming solution on a substrate to form a thin film, and then subjecting the thin film to a heat treatment, wherein the dielectric forming solution is an organic solvent. The above-mentioned item [1], characterized in that a solution comprising a compound of element A, a compound of element R, a compound of element C and a compound of element G soluble in the organic solvent is used.
A method for producing the dielectric composition described.

[4] Compound of element A, compound of element C,
The dielectric material according to the above item [1], wherein a colloidal sol containing a compound of the element B and a compound of the element G is heat-treated at a temperature at which each compound in the colloidal sol can be converted into an oxide. A method for producing a composition.

[5] Oxide of element A, oxide of element C,
The method for producing a dielectric composition according to the above item [1], wherein a film is formed by sputtering using an oxide sintering target containing an oxide of element B and an oxide of element G.

[6] A glass substrate, a ceramic substrate or a metal thin film, a glass substrate or a ceramic substrate coated with a conductive oxide thin film, a metal foil or a semiconductor substrate, on which the dielectric composition according to the above item [1] is applied. A thin film capacitor characterized by being formed into a thin film.

The present invention will be described in more detail below. In the present invention, Ca, Sr, B defined as element A
a, Pb, La, Ce, Pr, Nd, Pm, Sm, E
u, Gd, Tb, Dy, Ho, Er, Tm, Yb, L
A compound of one or more elements selected from u and Y (hereinafter referred to as a compound of element A), and one or two selected from Bi, Sc, Sb, Cr and Tl defined as element C. One or more compounds (hereinafter referred to as a compound of element C), Ti, Ta, Hf, W, Mo, Nb defined as element R,
A compound of one or more elements selected from Zr (hereinafter referred to as a compound of element R) and one selected from B, As, Sb, Si, Ge, Te and P defined as element G Alternatively, when a compound of two or more elements (hereinafter referred to as a compound of the element G) is heat-treated in a mixture of these compounds, the compound represented by the general formula (1)

Embedded image To obtain a dielectric composition satisfying s (Au Cv Bw Ox)-(1-s) (AOy-bCOr-aGOz) (1), the compounds are mixed and then converted into oxides. The dielectric composition is obtained by heat treatment at a temperature that allows conversion.

In the dielectric composition represented by the general formula (1), (Au Cv Bw Ox) represents a dielectric crystal phase,
(AOy-bCOr-aGOz) represents a glass phase. s
Represents the proportion of the crystal phase (molar fraction), and (1-s) represents the proportion of the glass phase (mol fraction). s is 0.3 <s ≦ 0.
It is in the range of 95. When s is 0.3 or less, desired dielectric properties cannot be obtained, and when it exceeds 0.95, it is difficult to generate a crystal phase and high temperature is required. In order to control the grain size of the crystal phase, the generation temperature and the like as desired, s may be in the above range.

Y, r and z represent the number of oxygen, y = 1 when A is divalent, y = 1.5 when A is trivalent, and C
Is trivalent, r = 1.5, when C is tetravalent, r = 2,
When C is pentavalent, r = 2.5; when C is hexavalent, r = 3
And z = 1.5 when G is trivalent, z = 2 when G is tetravalent, and z = 2.5 when G is pentavalent. a and b represent real numbers, and 1/19 ≦ a ≦ 2, 0.5 ≦ b / a ≦
It is in the range of 7.

U, v, w and x are real numbers that are determined so that the total charge is zero. y, r and z represent the number of oxygen, y = 1 when A is divalent, and y = when A is trivalent
1.5, r = 1.5 when C is trivalent, r = 2 when C is tetravalent, r = 2.5 when C is pentavalent, and C is 6
When the valence is r = 3, when G is trivalent, z = 1.
When 5 and G are tetravalent, z = 2, and when G is pentavalent, z =
It is 2.5.

X is A, C and R due to the requirement of electrical neutrality.
It is 1/2 of the total valence number obtained by multiplying the valence number of each ion constituting the ion by the mole fraction. b represents the number of moles of the glass phase forming oxide based on the element. For example, 1 mol of BO _1.5 in the case of boric acid (B ₂ O _3), 1 mol of PO _2.5 in the case of P ₂ O _5, in the case of SiO ₂ to the SiO ₂ is 1 mol.

A is G of elements A and R existing in the glass phase
The molar ratio is 1/19 to 2 times, and more preferably 1/9 to 1 times. When a is smaller than 1/19, A and R escape from the compound in the crystal phase to reduce the amount of the crystal phase, and when a is larger than 2, extra AO and RO are precipitated and the crystal phase is also formed. Decrease.

In the production method of the present invention, the compound of the element A, the compound of the element C, the compound of the element B and the compound of the element G, which are oxides or raw materials which can be converted into oxides, are atomized. , Molecules or aggregates thereof, and mixed in the form of clusters, oligomers or microparticles, the size of which is less than 0.1 μm in diameter, the mixture being formed at the same time as or after the formation of the mixture, Is heat-treated at a temperature at which it can be converted into an oxide. When such a dense mixed state is achieved, that state already corresponds to the glass state in the conventional crystallized glass method. This eliminates the need for the high temperature process in glass manufacturing that was necessary in the conventional method.

However, since it is just a mixture as it is, it is necessary to crystallize it by heating or the like. The timing of heating also depends on the process of making the mixture.
That is, when forming a thin film dielectric, for example, sputtering, CVD, vapor deposition, coating pyrolysis of organic compounds,
When the application of colloidal sol or the like is used, it is possible to heat the substrate during film formation or to use plasma to cause the formation of the mixture and the crystallization thereof at the same time. It is also possible to carry out film formation at a low temperature, obtain a mixture, and then heat to crystallize. When a powder is obtained, it is generally difficult to heat the mixture at the same time as it is synthesized, and after the mixture is obtained, heat treatment is performed to perform crystallization.

The degree of crystallization can be controlled by adjusting the degree of heat treatment. That is, in the dielectric composition represented by the general formula (1) of the present invention, the ratio of the generated crystal phase (Au Cv Bw Ox) varies depending on the degree of heat treatment, and its maximum value is equal to s. When the reaction rate is f, the molar fraction of the crystalline phase in the final product is (f
Xs). Generally, the higher the heating temperature and the longer the heating time, the more accelerated the crystallization.

The compound of the element A, the compound of the element C, the compound of the element B, and the compound of the element G, which are oxides or raw materials which can be converted into oxides, are composed of atoms, molecules or an aggregate thereof. As a method of mixing in the state of clusters, oligomers or fine particles whose size is less than 0.1 μm in diameter, a vacuum process such as sputtering, CVD, vapor deposition, or a method using a metal compound soluble in an organic solvent , A method using a colloidal sol such as silica colloid, a method using a water-soluble metal compound, and the like.

When the sputtering method is used as the raw material, an oxide corresponding to the composition of the above-mentioned general formula (1), that is, PbO, BaO, Li ₂ O, Na ₂ O,
K ₂ O, MgO, CaO, SrO, TiO ₂ , Zr
O ₂ , SnO ₂ , ZnO, FeO, CoO, NiO, N
b ₂ O ₅ , Ta ₂ O ₅ , W ₂ O ₅ , La ₂ O ₃ , Y ₂ O
₃ , B ₂ O ₃ , As ₂ O ₃ , Sb ₂ O ₃ , SiO ₂ , G
The target of each compound such as eO ₂ and TeO ₂ is used as necessary, and the multi-target sputtering in which the composition and the film thickness are controlled by the sputtering time of the target of each compound, or premixed with a desired composition and sintered Examples thereof include a method of sputtering using a target of a dielectric composition, reactive sputtering using a reactive gas (especially oxygen), and the like.

When the CVD method is applied, the following compounds can be mentioned as the compound of the element A used as a raw material.

Organic lead compounds such as 4-ethyllead and bisdipivaloylmethanatolead, or lead compounds of halides such as lead chloride Barium ethoxide, barium isopropoxide, organic barium compounds such as bisdipivaloyl barium , Or a barium compound of a halide such as barium chloride

Calcium ethoxide, calcium isopropoxide, bisdipivaloyl calcium and other organic calcium compounds, or halide calcium compounds such as calcium chloride Strontium ethoxide, strontium isopropoxide, bisdipivaloyl strontium, etc. Organic strontium compounds, or halide strontium chloride and other strontium compounds

Organic lanthanum compounds such as lanthanum ethoxide, lanthanum acetylacetonate and trisdipivaloyl lanthanum, or lanthanum compounds of halides such as lanthanum chloride yttrium ethoxide, yttrium acetylacetonate, tris dipivaloyl yttrium etc. Organic yttrium compounds or yttrium compounds of halides such as yttrium chloride

Cerium compounds such as cerium ethoxide, praseodymium compounds such as praseodymium ethoxide, and other organometallic compounds such as neodymium ethoxide, trisdipivaloyl gadolinium, and trisdipivaloyl terbium.

When the CVD method is applied, examples of the compound of the element R used as a raw material include the following compounds.

Organic titanium compounds such as titanium ethoxide, titanium isopropoxide, titanium butoxide, titanium acetate, or titanium compounds of halides such as titanium tetrachloride Organic compounds such as zirconium ethoxide, zirconium isopropoxide, zirconium butoxide Zirconium compound or zirconium compound of halide such as zirconium tetrachloride

Organic tantalum compounds such as pentaethyl tantalum, organic hafnium compounds such as hafnium ethoxide, tungsten compounds of halides such as tungsten chloride, molybdenum compounds of halides such as molybdenum chloride, and organic niobium compounds such as niobium ethoxide.

When the CVD method is applied, the following compounds can be mentioned as the compound of the element G used as a raw material.

Boron, triethylboron, trimethylboron, and other boron compounds Arsine, triethylarsenic, trimethylarsenic, and other arsenic compounds Triethylantimony, trimethylantimony, and other antimony compounds Silane, disilane, tetramethylsilane, tetraethylsilane, tetrachloride Silicon compounds such as silicon, tetraethoxysilane, tetramethoxysilane

Germanium compounds such as germanium hydride, tetramethyl germanium, tetraethyl germanium, germanium tetrachloride, tetraethoxy germanium and tetramethoxy germanium Tellurium hydride, tetramethyl tellurium, tetraethyl tellurium, tellurium tetrachloride, tetraethoxy tellurium, tetramethoxy Tellurium compounds such as tellurium Phosphorus compounds such as phosphorus oxychloride

When the CVD method is applied, the following compounds can be mentioned as the compound of the element C used as a raw material.

Organic bismuth compounds such as bismuth ethoxide, bismuth acetylacetonate and bisdipivaloylbismuth, or bismuth compounds of halides such as bismuth chloride scandium ethoxide, scandium acetylacetonate and bisdipivaloyl scandium Organic scandium compounds or scandium compounds of halides such as scandium chloride

Organic antimony compounds such as antimony ethoxide, antimony acetylacetonate and bisdipivaloyl antimony, or antimony compounds of halides such as antimony chloride Chromium ethoxide, chromium acetylacetonate, bisdipivaloyl chromium etc. Organic chromium compounds or halogenated chromium compounds such as chromium chloride

Organic thallium compounds such as thallium ethoxide, thallium acetylacetonate, and bisdipivaloyl thallium, or halide thallium compounds such as thallium chloride.

These compounds are represented by the general formula (1)

(In the formula, A is Ca, Sr, Ba, Pb, La,
Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, D
1 selected from y, Ho, Er, Tm, Yb, Lu and Y
Or 2 or more elements, C is Bi, Sc, Sb, Cr, T
1 or 2 or more elements selected from l, R is Ti, T
a, Hf, W, Mo, Nb, one or more elements selected from Zr, G is B, As, Sb, Si, Ge, T
It is one or more elements selected from e and P.
s, a, and b represent real numbers, and 0.3 <s ≦ 0.95, 1
/ 19 ≦ a ≦ 2 and 0.5 ≦ b / a ≦ 7. s
Represents the mole fraction of the crystal phase. u, v, w, and x are real numbers determined so that the total electric charge becomes zero. y, r, and z represent oxygen numbers, and when A is divalent, y = 1 and A is 3
When the valence is y = 1.5, when C is trivalent, r =
1.5, r = 2 when C is tetravalent, r when C is pentavalent
= 2.5, r = 3 when C is hexavalent, z = 1.5 when G is trivalent, z = 2 when G is tetravalent, and z when G is pentavalent. = 2.5. ), And then transported with a gas such as argon, nitrogen, oxygen, etc., and deposited on a substrate or in a reactor to obtain an oxide thin film or powder.

As for the mixing method, the method of mixing each compound vaporized by an individual vaporizer in the middle of the pipe, which is usually used, has a good controllability, but all the raw materials are previously mixed.
It may be vaporized after being mixed as a compound having almost the same vapor pressure. The gas flow rate is between 100 milliliters and 10 liters / minute, depending on the production rate.

It is sufficient that the sputtering container has corrosion resistance and can be sputtered under the condition of being shielded from the outside air.
The container wall or the substrate may be heated to 300 to 900 ° C., but when heated, the crystal phase directly precipitates.
Since it is generally amorphous when not heated, the thin film is taken out from the sputtering apparatus and then heated to precipitate crystals. The heating means will be described later.

In the case of the vapor deposition method, Ca, Sr, Ba, P
b, La, Ce, Pr, Nd, Pm, Sm, Eu, G
d, Tb, Ho, Er, Tm, Yb, Lu, Y, Bi,
Sc, Sb, Cr, Tl, Ti, Ta, Hf, W, M
O, Nb, Zr, B, As, Si, Ge, Te, P elemental metals, or these alloys mixed in a desired composition to give the composition represented by the general formula (1), a tungsten boat. , Is heated by an electron beam or the like to be deposited on the substrate. When the obtained thin film is an alloy, it is converted into an oxide by performing a treatment such as heating in an oxidizing atmosphere. The heating means and the like will be described later.

As a dielectric forming solution, an organic solvent, a compound of the element A, a compound of the element R, and a compound of the element C soluble in the organic solvent are used.
The method of producing a dielectric composition by applying a solution of the dielectric-forming solution onto a substrate to form a thin film by using a solution consisting of the compound of For example, it is performed as follows.

In the method using a metal compound soluble in an organic solvent, as the compound of the element A, for example, the following compounds can be used. Examples of the lead compound include diethoxylead, diisopropoxylead, dimethoxyethoxylead, lead acetylacenate, lead formate, lead acetate and the like. Examples of the barium compound include dimethoxy barium, diethoxy barium, diisopropoxy barium, dibutoxy barium, barium acetate, barium acetylacetonate, and the like.

Examples of the magnesium compound include dimethoxy magnesium, diethoxy magnesium, diisopropoxy magnesium, dibutoxy magnesium and the like. Examples of the calcium compound include dimethoxy calcium, diethoxy calcium, diisopropoxy calcium, dibutoxy calcium and the like.

As the strontium compound, for example,
Examples thereof include dimethoxystrontium, diethoxystrontium, diisopropoxystrontium and dibutoxystrontium.

Examples of the lanthanum compound include trimethoxylanthanum, triethoxylanthanum, triisopropoxylanthanum, tributoxylanthanum and lanthanum chloride. Examples of the yttrium compound include trimethoxy yttrium, triethoxy yttrium, triisopropoxy yttrium, tributoxy yttrium, yttrium chloride and the like.

In the method using a metal compound soluble in an organic solvent, as the compound of the element R, for example, the following compounds can be used. Examples of the titanium compound include tetramethoxytitanium, tetraethoxytitanium, tetraisopropoxytitanium, tetrabutoxytitanium, titanium tetrachloride and the like.

Examples of the zirconium compound include tetramethoxyzirconium, tetraethoxyzirconium, tetraisopropoxyzirconium, tetrabutoxyzirconium and zirconium tetrachloride.
Examples of the tantalum compound include pentamethoxy tantalum, tantalum acetylacetonate, tantalum pentachloride and the like.

Examples of the niobium compound include pentamethoxy niobium, pentaethoxy niobium, pentaisopropoxy niobium, pentabtox niobium, niobium chloride and the like. Examples of the tantalum compound include pentamethoxy tantalum, pentaethoxy tantalum, pentaisopropoxy tantalum, pentabtox tantalum, tantalum chloride and the like.

Examples of the tungsten compound include pentamethoxytungsten, pentaethoxytungsten, pentaisopropoxytungsten, pentabtoxytungsten, tungsten chloride and the like.

In the method of using a metal compound soluble in an organic solvent, the following compounds can be used as the compound of the element G, for example.

Examples of the boron compound include triethyl borate, trimethyl borate, trimethoxyethoxyboron, triphenyl borate, boric acid and the like. Examples of the arsenic compound include triethyl arsenate, trimethyl arsenate, trimethoxyethoxyarsenic, triphenyl arsenate, and the like.

Examples of the antimony compound include triethyl antimonate, trimethyl antimonate, trimethoxyethoxy antimony, triphenyl antimonate and the like. Examples of the silicon compound include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, silicon tetrachloride, and the like.

Examples of the germanium compound include tetramethoxygermanium, tetraethoxygermanium, tetraisopropoxygermanium, tetrabutoxygermanium, germanium tetrachloride and the like.
Examples of the tellurium compound include tetramethoxy tellurium, tetraethoxy tellurium, tetraisopropoxy tellurium, tetrabutoxy tellurium, tellurium tetrachloride and the like. Examples of phosphorus compounds include trimethoxyphosphonyl and phosphorus oxychloride.

In the method using a metal compound soluble in an organic solvent, examples of the compound of the element C include the following.

Organic bismuth compounds such as bismuth ethoxide, bismuth acetylacetonate and bisdipivaloylbismuth, or halide bismuth compounds such as bismuth chloride. Organic scandium compounds such as scandium ethoxide, scandium acetylacetonate and bisdipivaloyl scandium, or halide scandium compounds such as scandium chloride.

Organic antimony compounds such as antimony ethoxide, antimony acetylacetonate and bisdipivaloyl antimony, or halide antimony compounds such as antimony chloride. Organic chromium compounds such as chromium ethoxide, chromium acetylacetonate and bisdipivaloyl chromium, or halide chromium compounds such as chromium chloride.

Organic thallium compounds such as thallium ethoxide, thallium acetylacetonate and bisdipivaloyl thallium, or halide thallium compounds such as thallium chloride.

The organic solvent used is the above-mentioned lead compound, barium compound, magnesium compound, calcium compound, strontium compound, lanthanum compound,
Which can dissolve yttrium compounds, bismuth compounds, titanium compounds, zirconium compounds, niobium compounds, tantalum compounds, tungsten compounds, boron compounds, arsenic compounds, antimony compounds, silicon compounds, germanium compounds, tellurium compounds, phosphorus compounds, etc. Although such an organic solvent may be used,

Preference is given to alcohols such as methanol, ethanol, propanol, butanol, pentanol, methoxyethanol and ethoxyethanol, aromatic hydrocarbons such as benzene, toluene and xylene, and aliphatic hydrocarbons such as pentane, hexane, heptane and octane. Ethers such as hydrocarbons, dioxane and tetrahydrofuran,
Ketones such as acetone, methyl ethyl ketone and diethyl ketone, carboxylic acid esters such as methyl acetate, ethyl acetate and ethyl formate, β-diketones such as acetylacetone, benzoylacetone and dibenzoylacetone, amides such as dimethylformamide and dimethylacetamide. And the like, and these organic solvents may be used alone or in combination of two or more kinds.

The dielectric forming solution may be prepared by dissolving the compound of the element A, the compound of the element B, the compound of the element C, the compound of the element G in an organic solvent and mixing them at room temperature, or A method of reacting the compound in an organic solvent under heating can be mentioned. Further, the coating solution can be polymerized to improve the quality of the coating film. In that case, an appropriate amount of water or a solution obtained by diluting water in the above-mentioned organic solvent in an appropriate ratio may be added during mixing or reaction.

The temperature for heating in the organic solvent varies depending on the kind of the compound and is not necessarily limited, but is generally 60 to 150 ° C.

The concentration of the metal compound in the dielectric forming solution varies depending on the kind of the metal compound, but is preferably 5 to 80% by weight in terms of oxide, and more preferably 10 to 5%.
Applied at 0% by weight.

A carboxylic acid (having 6 to 20 carbon atoms), glycol, amine or the like for stabilization may be added to the dielectric forming solution. In order to improve the workability of the dielectric forming solution, for example, polymer substances such as polyol and ethyl cellulose, methyl cellosolve, ethyl cellosolve,
High boiling compounds such as acetylacetone, glycerin,
A nonionic or anionic surfactant or the like can be added.

Compound of element A, compound of element C, element B
In the method for producing a dielectric composition according to the present invention, a colloidal sol containing the compound of the present invention and the compound of the element G is heat-treated at a temperature at which each compound in the colloidal sol can be converted into an oxide. A colloidal sol obtained by partially hydrolyzing the above-mentioned dielectric forming solution can be used. A colloidal sol obtained by mixing a colloidal sol of a compound of the element A, a compound of the element C, a compound of the element B and a compound of the element G can also be used.

As a method of using the thus obtained dielectric forming solution or colloidal sol, the dielectric forming solution or colloidal sol is applied on a substrate to form a thin film and then heat-treated to form a film. And a method of heat treatment after molding into a bulk. It is also possible to employ a method in which the dielectric forming solution or colloidal sol is dried or hydrolyzed to obtain a powder and then heat treatment is performed.

As a method for forming a film on a substrate, a known coating method such as a dipping method, a spray method, a spinner method or a brush coating method can be used. The thin film thus obtained can be further dried if necessary.

The molding into a bulk object can be carried out by a known method such as slip casting, colloidal pressing, tape casting or the like using the above-mentioned dielectric forming solution or colloidal sol. Further, the dielectric-forming solution prepared as described above is further hydrolyzed with an excess amount of water, and the gel powder obtained by drying is crushed if necessary and calcined, then, dry pressing, slip casting, It can also be formed by a method such as tape casting.

The hydrolysis is carried out by reacting the compound solution with an excess amount of water that is at least twice the number of moles of metal contained in the solution, or with a solution containing water, or by simply leaving it in the air and leaving it in the air. It may be carried out by reacting with water. In this way, the oxide precursor powder can be obtained.

As a gelling method, first, drying can be mentioned. Generally, the sol loses its repulsive force and gels when the dispersion medium is exhausted. This method can be applied to all sols. In addition, even if the Coulomb repulsion is suppressed by adjusting the pH or adding salt, gelation occurs. The acidic sol gels in the neutral-alkaline region by the addition of, for example, ammonia, caustic soda, etc. The alkaline sol gels in the neutral-acidic region by the addition of acids such as hydrochloric acid and nitric acid. When a salt such as potassium chloride, calcium chloride or aluminum nitrate is added to increase the concentration of the electrolyte in the aqueous colloid solution, the Coulomb repulsion force is shielded and reduced, resulting in gelation.
Gelation can also occur by adding an organic solvent such as isopropanol or acetone.

The gel or precipitate thus obtained is dried and / or calcined so that the compounds of element A, element C and element G are appropriately adjusted so that the area of each compound is 0.1 μm or less. A powder of the above size is obtained, which is used as a paste raw material and can be molded by a known method. Examples of the molding method include a method of forming a film as a coating liquid on a substrate and a method of molding into a bulk, as described above.

In the method of mixing using a water-soluble metal compound and coprecipitating as necessary to obtain a mixture, the compound of the element A includes the following compounds.

Examples of the lead compound include lead nitrate, lead acetate, lead chloride and the like. Examples of the barium compound include barium nitrate, barium acetate, barium chloride and the like. Examples of the calcium compound include calcium nitrate, calcium acetate, calcium chloride and the like.

As the strontium compound, for example,
Examples thereof include strontium nitrate, strontium acetate, and strontium chloride. Examples of the lanthanum compound include lanthanum nitrate, lanthanum acetate, and lanthanum chloride. Examples of the yttrium compound include yttrium nitrate, yttrium acetate, and yttrium chloride.

Examples of the water-soluble R compound include the following compounds. As a titanium compound,
Examples thereof include titanyl nitrate, titanyl acetate, titanium tetrachloride, and titanyl sulfate. Examples of the zirconium compound include zirconyl nitrate, zirconyl acetate, zirconium tetrachloride, zirconyl sulfate and the like.

Examples of the niobium compound include niobium nitrate, niobium acetate, niobium chloride, niobium sulfate and the like. As the tantalum compound, for example, tantalum nitrate,
Examples thereof include tantalum acetate, tantalum chloride, tantalum sulfate and the like. Examples of the tungsten compound include tungsten nitrate, tungsten acetate, tungsten chloride, tungsten sulfate and the like.

Examples of the water-soluble G compound include the following compounds. Examples of the boron compound include boric acid. Examples of the arsenic compound include arsenic acid. Examples of the antimony compound include antimonic acid, antimony nitrate, antimony acetate, thymon chloride, antimony sulfate and the like.

Examples of the silicon compound include silicon tetrachloride and silicic acid. Examples of the germanium compound include germanium tetrachloride, germanium nitrate,
Examples thereof include germanium acetate. Examples of the tellurium compound include tellurium tetrachloride and tellurium nitrate. Examples of the phosphorus compound include phosphoric acid and the like.

The above compound soluble in water is represented by the general formula (1)

S (Au Cv Rw Ox)-(1-s) (AOy-bCOr-aGOz) (1) (wherein A is Ca, Sr, Ba, Pb, La, Ce, P
r, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
1 or 2 or more elements selected from o, Er, Tm, Yb, Lu and Y, C is 1 or 2 or more elements selected from Bi, Sc, Sb, Cr and Tl, R is Ti, Ta, H
One or more elements selected from f, W, Mo, Nb, and Zr, and G is one or more elements selected from B, As, Sb, Si, Ge, Te, and P. s, a and b represent real numbers, and 0.3 <s ≦ 0.95, 1/19 ≦
It is in the range of a ≦ 2 and 0.5 ≦ b / a ≦ 7. s represents the mole fraction of the crystal phase. u, v, w and x have zero total charge
Is a real number that is determined to be. y, r, and z represent oxygen numbers, y = 1 when A is divalent, y = 1.5 when A is trivalent, and r = 1.5 when C is trivalent, C
Is 4 when r is 2, r is 2.5 when C is 5,
When C is hexavalent, r = 3, and when G is trivalent, z =
1.5, z = 2 when G is tetravalent, z when G is pentavalent
= 2.5. ), Is carried together with a gas such as argon, nitrogen, oxygen, etc., and deposited on a substrate or in a reactor to obtain a thin film or a substrate.

Examples of the method of molding using the thus obtained dielectric forming solution include a method of forming a film as a coating solution on a substrate and a method of forming into a bulk.
Further, a precipitate is obtained by adjusting the pH, producing a sparingly soluble salt, etc., and drying and / or calcining the precipitate to obtain the element A,
R, C, and G compounds have an area of each compound of 0.1 μm
A powder having an appropriate size as described below is obtained, which is used as a paste raw material and can be formed into a desired shape by slip casting, dry pressing, or the like.

The pH for forming the precipitate varies depending on the metal, but it is generally preferable that the pH is 3 or higher, and around neutral. However, alkaline earth metal ions such as Sr are required to have a pH of about 11 or higher, and alkali metal ions do not precipitate by adjusting the pH. Therefore, in the case of alkaline earth metal ions, it is preferable to form a sparingly soluble salt, and precipitation is caused by addition of oxalic acid, sulfuric acid, citric acid and the like. When an alkali metal ion is used, water is removed from the system to lower the solubility and cause precipitation.

As a method for forming a film on a substrate, a known coating method such as a dipping method, a spray method, a spinner method or a brush coating method can be used. The thin film thus obtained is further dried if necessary. When molding into a bulk body, the compound solution obtained above may be molded by a known method such as slip casting, colloidal press, tape casting or the like.

The above-mentioned sputtering, vapor deposition, and CV
As a method for drying the powder obtained from D, the organic metal compound, the colloidal sol, the water-soluble metal compound, etc., a known drying means such as a rotary evaporator, a flaker, or an air bath can be used. In the case of a known constant temperature dryer or the like, the drying temperature can be about 100 to 300 ° C, and the calcination can be performed at about 300 to 900 ° C in an electric furnace, a gas furnace or the like if necessary.

As a method for firing the powder, electric resistance heating,
Known means such as plasma, high frequency, laser, etc. can be used.
The firing temperature varies depending on the composition, but it is necessary to set it to a temperature equal to or higher than the crystallization of the crystal phase.
The temperature is 1200 ° C, more preferably 500 to 1000 ° C. If it is lower than 400 ° C., the organic matter is not decomposed or crystallization does not proceed, and if it is higher than 1200 ° C., the composition is changed due to evaporation of elements, which is not preferable.

The firing atmosphere can be firing in air, in an inert gas, in a reducing atmosphere, or in an oxygen atmosphere when the crystal phase is easily reduced. The powder thus obtained is appropriately pulverized by a known method such as a ball mill, a vibration mill, a ladle machine, an attritor, etc. to be used as a paste raw material, or by a known method such as a dry press, a hydrostatic press and a slip casting. It is molded.

The powder thus obtained is a mixture of a large number of precipitated fine single crystals and a glass component. In order to separate only the fine single crystal from this, the glass component is dissolved in water, a dilute acid, a dilute alkali aqueous solution, or the like, and then filtration, centrifugation or the like is performed. Examples of the acid include nitric acid, hydrofluoric acid, hydrochloric acid, sulfuric acid, acetic acid and the like. Examples of the alkali include ammonia water, caustic soda, caustic potash, and the like. These are used after diluting to a concentration of 5 to 50%.

The substrate used in the present invention has smoothness,
Any material can be used as long as it has the required heat resistance during heat treatment during the process. For example, a glass substrate,
Examples thereof include a ceramic substrate, a glass or ceramic substrate coated with a metal thin film or a conductive oxide, a metal foil, and a semiconductive substrate.

Specifically, substrates such as quartz glass, alumina, zirconia, mica, silicon, gold, platinum, palladium, silver, copper, chromium, titanium, aluminum, tantalum, gold-chromium, palladium-silver, platinum-tantalum. ,
Platinum-titanium, quartz glass coated with a thin film such as indium oxide doped with tin or antimony, substrates such as alumina, zirconia, mica, silicon, gold, platinum, palladium, silver, copper, nickel, nickel-chromium, aluminum, etc. The metal substrate of.

As described above, as a method for heating the film obtained by coating the substrate or the molded article, electric resistance heating,
Known means such as plasma, high frequency, laser, etc. can be used.
The heating temperature varies depending on the manufacturing method, but in the case of the sputtering method, the CVD method, etc., the film is formed while heating the substrate to about 200 to 700 ° C., and the subsequent heat treatment may not be necessary.
Furthermore, you may heat-process about 500-900 degreeC. In the case of the vapor deposition method, it is generally 500-in air or in an oxidizing atmosphere.
A heat treatment at about 900 ° C. is performed.

In the case of a method using a metal compound soluble in an organic solvent, a metal compound soluble in water, or a colloidal sol, it depends on the concentration of the metal compound in the solvent, the type of solvent, the type of substrate, etc. It is necessary to raise the temperature above the crystallization of the body, usually about 400 to 1200 ° C., preferably about 500 to
It is 1000 ° C. If it is lower than 400 ° C., the organic matter is not decomposed or crystallization does not proceed, and if it is higher than 1200 ° C., the composition changes due to evaporation of elements, which is not preferable.

In order to densely sinter the bulk powder and the compact, depending on the composition, sintering at 500 to 1000 ° C. is performed as heat treatment. The atmosphere of the heat treatment may be air, an inert gas, or a reducing atmosphere,
When the dielectric is easily reduced, heat treatment (baking) can be performed in an oxygen atmosphere.

[0098]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples.

For the measurement of the dielectric properties, 100 Au electrodes were formed on the dielectric film by sputtering, and then the impedance was measured by an impedance analyzer (YHP4275A: Yokogawa Hewlett-Packard Co.). The insulation rate was defined as the number of electrodes that were not short-circuited out of 100 electrodes. In addition, a DC voltage is applied to measure the dielectric breakdown voltage using a super insulation resistance tester (YHP43
29A: Yokogawa Hewlett Packard). The crystal phase was confirmed by powder X-ray diffraction, and the crystal shape was observed by a scanning electron microscope.

Example 1 Strontium diethoxide, bismuth ethoxide, tantalum pentaisopropoxide and tetraethoxysilane were mixed with 0.9 (SrBi ₂ Ta ₂ O ₉ ) -0.1 (Sr.
O-Bi ₂ O ₃ -SiO ₂ ) and mixed in a 1: 1 (weight ratio) mixed solvent of isopropanol-toluene to synthesize a dielectric forming solution of 10% by weight in terms of oxide. did.

A Pt / Ti (0.5 /
(0.05 μm) coated on a Si substrate coated with a film by a spinner under the condition of 2500 rotations, and then at 450 ° C. for 30 minutes.
Heat treatment in oxygen for 2 minutes, the above coating and heat treatment (baking) are repeated twice, and finally baking is performed in the air at 600 ° C. for 1 hour to obtain a dense film having a thickness of 0.2 μm. A transparent thin film dielectric was obtained. Generation of SrBi ₂ Ta ₂ O ₉ is X
Confirmed by line diffraction. The dielectric constant is 140 and the spontaneous polarization is 5.
μC / cm ² , insulation rate is 100%, dielectric breakdown is 3
It did not occur up to 0V.

Example 2 Lead diethoxide, niobium pentaisopropoxide,
Bismuth ethoxide and trimethyl boron were added to 0.7
(PbBi ₂ Nb ₂ O ₉ ) -0.3 (PbO-0.5B
i ₂ O ₃ -0.25B ₂ O ₃ ) in a proportion such as
It was dissolved in a 1: 1 (weight ratio) mixed solvent of isopropanol-toluene to prepare a fine single crystal powder forming solution of 15% by weight in terms of oxide. The solvent was removed from this solution by a rotary evaporator, and then dried at 130 ° C. for 30 minutes,
A gel powder was obtained. This powder was kept at 800 ° C. for 1 hour to precipitate a fine single crystal powder. This was further washed in 1 N nitric acid at 40 ° C. and then filtered to obtain only fine single crystals. Formation of a crystalline phase was confirmed by X-ray diffraction.

The dielectric composition of the present invention is formed into a thin film on a glass or ceramic substrate, a glass or ceramic substrate coated with a metal thin film or a conductive oxide thin film, a metal foil or a semiconductive substrate. By doing so, a thin film capacitor can be obtained.

[0104]

According to the method of the present invention, the manufacturing cost is low and the insulating property is high and the reliability is high as compared with the conventional method in which the dielectric powder is slurried and obtained by the doctor blade method or the like. A body composition is obtained. Compared with conventional glass-ceramics that have been melted, the proportion of the crystal phase is high, and those having a high relative dielectric constant can be obtained without undergoing a high-temperature treatment such as melting, so that the capacity can be increased. Also,
The dielectric composition of the present invention has improved insulation characteristics and reduced defective rate. This opens the way for practical application to the ferroelectric memory, which has been difficult to apply because of its difficulty in reliability and insulation rate, and its industrial value is great.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location H01G 4/33 7924-5E H01G 4/30 301E 4/30 301 C30B 7/14 // C30B 7/14 7924- 5E H01G 4/06 102

Claims (6)

[Claims] 1. General formula (1): s (Au Cv Rw Ox)-(1-s) (AOy-bCOr-aGOz) (1) (wherein A is Ca, Sr, Ba, Pb). , La, Ce, P
r, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
1 or 2 or more elements selected from o, Er, Tm, Yb, Lu and Y, C is 1 or 2 or more elements selected from Bi, Sc, Sb, Cr and Tl, R is Ti, Ta, H
One or more elements selected from f, W, Mo, Nb, and Zr, and G is one or more elements selected from B, As, Sb, Si, Ge, Te, and P. s, a and b represent real numbers, and 0.3 <s ≦ 0.95, 1/19 ≦
It is in the range of a ≦ 2 and 0.5 ≦ b / a ≦ 7. s represents the mole fraction of the crystal phase. u, v, w and x have zero total charge
Is a real number that is determined to be. y, r, and z represent the oxygen number, y = 1 when A is divalent, y = 1.5 when A is trivalent, and r = 1.5 when C is trivalent, C
Is 4 when r is 2, r is 2.5 when C is 5,
When C is hexavalent, r = 3, and when G is trivalent, z =
1.5, z = 2 when G is tetravalent, z when G is pentavalent
= 2.5. ) The dielectric composition having a composition represented by: 2. A compound of the element A, a compound of the element C, a compound of the element B and a compound of the element G, which are oxides or raw materials that can be converted into oxides, are atoms, molecules or an assembly thereof. A mixture of a body and a cluster, an oligomer or a fine particle whose size is less than 0.1 μm in diameter, and heat-treating the mixture at a temperature at which it can be converted into an oxide. The method for producing a dielectric composition according to claim 1. 3. A method for producing a dielectric composition by applying a dielectric forming solution on a substrate to form a thin film, and then subjecting the thin film to a heat treatment, wherein the organic solvent and the organic solvent are used as the dielectric forming solution. The method for producing a dielectric composition according to claim 1, wherein a solution comprising a compound of element A, a compound of element R, a compound of element C, and a compound of element G that is soluble in an organic solvent is used. 4. A compound of element A, a compound of element C, and element B
2. A colloidal sol containing the compound of claim 1 and the compound of element G is heat-treated at a temperature at which each compound in the colloidal sol can be converted into an oxide.
A method for producing a dielectric composition according to claim 1. 5. An oxide of element A, an oxide of element C, an element B
The method for producing a dielectric composition according to claim 1, wherein a film is formed by sputtering using an oxide sintering target containing the oxide of 1. and the oxide of element G. 6. A thin film prepared by coating the dielectric composition according to claim 1 on a glass substrate, a ceramic substrate or a metal thin film, a glass substrate or a ceramic substrate coated with a conductive oxide thin film, a metal foil or a semiconductor substrate. Thin film capacitor characterized by being formed into a shape.