JP2676775B2 - Thin film dielectric and method of manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thin film dielectric and a method for manufacturing the same, and more particularly to a thin film dielectric having a high relative dielectric constant and good temperature characteristics and a method for manufacturing the same. It is a thing.

<Prior Art> Barium titanate and lead titanate have hitherto been used as ceramic capacitors and piezoelectric elements because of their excellent dielectric and piezoelectric characteristics.

By the way, as is well known, (Where C is capacitance, S is area, d is electrode distance, ε
_o is the vacuum dielectric constant, ε _r is the relative dielectric constant, and n is the number of laminated layers. ), It is generally used by stacking in order to increase the capacity.

The manufacturing method of the multilayer capacitor is to mix the dielectric powder of 0.5 μm to 5 μm obtained by the solid phase reaction or the solution reaction with a binder or a solvent to manufacture a slurry, and make the slurry into a thin plate shape by a doctor flade method or the like. The steps of forming, laminating dozens to several tens of layers, and firing at about 1200 to about 1300 ° C. are taken. However, this method has a drawback that the production cost is high because firing is required to obtain the dielectric powder and firing of the formed green sheet.

In addition, in recent years, when product miniaturization is required, it is natural that multilayer ceramic capacitors also need to be miniaturized, but in the above method where one dielectric layer is thick, the number of layers required for high capacity is naturally increased. There is a limit to the increase of.

To satisfy this requirement, a method of thinning the dielectric layer can be considered as is clear from the above formula. In the case of conventional multilayer capacitors, one layer is about 20-40 μm,
If the thickness can be reduced to about m, not only the size can be reduced but also the capacity can be remarkably improved.

For this reason, vapor phase methods such as sputtering, vacuum deposition, and CVD have been attempted as methods for thinning the dielectric, but these methods require expensive equipment and the dielectric material It has a drawback that it is difficult to control stoichiometry and a dielectric having a desired composition cannot be obtained.

Aside from this, there is known a method of producing a thin film dielectric by applying an organometallic compound and thermally decomposing it. For example, a method to obtain a transparent thin film barium titanate by mixing barium naphthenate and a butanol solution of Ti alkoxide at a ratio of Ba: Ti = 1: 1 and coating on a glass substrate, followed by baking in an electric furnace. Bulletin (Ceramic Bull
etin) Vol. 55 No. 12 (1976) p1064-1065].

Lead acetate and Ti alkoxide in methoxyethanol
A method to obtain thin film lead titanate by mixing and reacting at a ratio of Pb: Ti = 1: 1 and coating on a quartz glass substrate and baking in an electric furnace [British Ceramic Proceeding (36) p107-121) 198
Five)〕.

A solution of titanium alkoxide and alkaline earth metal alkoxide dissolved in an organic solvent in the presence of carboxylic acid is applied on the substrate and pyrolyzed to form a SrTiO ₃ film, CaTi
A method for obtaining an O ₃ film (JP-A-58-198491).

One or two of metal alkoxides or multimers thereof
A method of obtaining a BaTiO ₃ film by applying a solution in which one or more kinds and one or more kinds of metal chelate compounds are dissolved onto a substrate and thermally decomposing the solution (JP-A-59-213603).

A mixture of a titanium compound and a lead compound, or a β-diketone solution of a reaction product of a titanium compound and a lead compound is applied on a heat-resistant substrate, heated and baked, and further coating of the ketone solution and heating and baking are repeated to form a PbTiO ₃ thin film. An example of synthesizing (JP-A-59-139617).

A solution obtained by dissolving a mixture of a lanthanum compound, an organic titanium compound, an organic zirconium compound and a lead compound or a reaction product in an organic solvent such as β-diketone is coated on a substrate, dried and baked to _obtain Pb _0.905 La _0.095 (Zr _0.65 T
Method for obtaining a thin film having a composition such as i _0.35 ) O ₃
-200403 publication).

Etc., thin films having various compositions and methods for manufacturing the same are known.

However ~ Among the prior art BaTiO _3, Sr
Although there are synthesis examples of thin films such as TiO ₃ and CaTiO ₃ , there is no description of what dielectric properties these thin films show.

It has been shown that the PbTiO ₃ thin film has a dielectric constant of 150 to 170, but at this level of dielectric constant, the merit of increasing the capacity by thinning the film is extremely small.

On the other hand, Example 1 has a thickness of 2.5 μm and a relative dielectric constant of 988,
Pb _0.905 La with excellent dielectric constant of 0.05 and dielectric loss
_Although a thin film with a composition of _0.095 (Zr _0.65 Ti _0.35 ) O ₃ has been obtained, the thin film dielectric shows good dielectric properties, but the Curie point is near room temperature, so the change in dielectric constant with temperature is extremely poor. It has a drawback (temperature coefficient of capacitance 3000-4000ppm / ℃ at 25-125 ℃). As is well known, when the temperature change of the permittivity (temperature coefficient of capacitance) is large, it is not possible to obtain a stable charge amount in a practical temperature range when applied as a capacitor, and in combination with a coil and a resistor When assembled, the circuit constants change greatly, which is a fatal drawback that it tends to cause defects and failures in application to electronic equipment.

<Problems to be Solved by the Invention> In view of such circumstances, the present inventor has made a thin film having a thickness of about 10 μm or less and a relative dielectric constant of about 300 or more and −1000 ppm / ° C. to +1000 p.
As a result of diligent studies to find out a thin film dielectric having a temperature coefficient of capacitance of pm / ° C. and excellent in dielectric properties, and a manufacturing method thereof, the present invention has finally been completed.

<Means for Solving the Problems> That is, the present invention is: (1) Composition formula (Pb _1-x M _x ) TiO ₃ (wherein 0.1 ≦ x ≦ 0.9, M represents one or more of alkaline earth metals) .) Average film thickness represented by 0.1 μm to 10 μm
m, relative permittivity of 300 or more, temperature coefficient of capacitance −1000 ppm /
Thin film dielectrics with physical properties of ℃ to + 1000ppm / ℃, and (2) Lead compounds, alkaline earth metal compounds and titanium compounds soluble in organic solvents are dissolved or reacted in organic solvents to form dielectrics. A solution is synthesized, and then the solution is applied on a smooth substrate to form a thin film, and the thin film is heat-treated, or the application of the solution on the substrate and the heat treatment are repeated to obtain an average film thickness of 0.1 μm to 10 μm. Of the metal oxide represented by the composition formula (Pb _1-x M _x ) TiO ₃ (where 0.1 ≦ x ≦ 0.9, M represents one or more alkaline earth metals). Another object of the present invention is to provide a method for producing a characteristic thin film dielectric.

 Hereinafter, the present invention will be described in more detail.

An organic solvent-soluble lead compound used in the practice of the present invention is represented by the formula PbXn (wherein X represents one or more selected from an alkyl group, an alkoxy group, an acyloxy group and a β-dikent group, and n is 2 Alternatively, a compound represented by the formula (4) can be used, and it is preferable that X has 14 or less carbon atoms, and more preferably 8 or less carbon atoms. When the number of carbon atoms exceeds 14, organic substances are difficult to decompose during thermal decomposition, and pores are easily formed, resulting in poor dielectric properties.

Specifically, monoacetoxymonomethyllead, monoacetoxymonoethyllead, monopropyloxymonopropyllead, and other monooxymonoalkylleads, monoacetoxymonomethoxylead, monoacetoxymonoethoxylead, monopropyloxymonopropoxylead, etc. Monoacyloxymonoalkoxy leads, dimethyllead, diethyllead, dipropyllead and other dialkylleads, dimethoxylead, diethoxylead, dipropoxylead, dibutoxylead and other alkoxides, monomethylmonoethoxylead, monoethylmonopropoxylead, mono Butyl monopentoxy lead and other monoalkyl monoalkoxy lead compounds, monoacetoxytriethyl lead, monopropyloxytributyl lead and other monoacyloxytrialkyl lead compounds, diacetoxydimethyl lead, dipropyloxydipropyl lead, etc. Acyloxyalkyl dialkyl lead compounds triacetoxy monoethyl lead, triacyloxy monoalkyl lead such as tri-propyloxy monobutyl lead,
Monoalkoxytrialkylleads such as monomethoxytriethyllead and monopropoxytributyllead; dialkoxydialkylleads such as diethoxydimethyllead and dipropoxydipropyllead; trimethoxymonoethyllead and tributoxymonobutyllead. Alkoxy monoalkyl leads,
Monoacetoxytriethoxylead, monopropyloxytributoxylead and other monoacyloxytrialkoxyleads, diacetoxydimethoxylead, dipropyloxydipropoxylead and other diacyloxydialkoxyleads, triacetoxymonoethoxylead, tripropyloxy Triacyloxymonoalkoxyleads such as monobutoxylead, tetraalkylleads such as tetramethyllead, tetraethyllead, and tetrabutyllead, tetraalkoxyleads such as tetramethoxylead, tetraethoxylead, and tetrapropoxylead, lead acetate, propion Lead acid, lead caproate, lead benzoate 2-
Lead carboxylates such as lead ethylhexanoate and β-diketones such as lead acetylacetonate and lead benzoylacetonate may be mentioned.

Examples of the alkaline earth metal compound soluble in an organic solvent include compounds represented by the formula MY ₂ (wherein M represents one or more selected from barium, strontium, and caldium, Y represents an alkyl group, an alkoxy group, an acyloxy group, β- A compound represented by one or more selected from diketone groups can be used, and Y preferably has 14 or less, preferably 8 or less carbon atoms.

If the carbon number exceeds 14, organic substances are likely to remain in the molded body after firing, and pores are easily formed, resulting in poor dielectric properties.

Specific examples of such a Ba compound include monoacetoxymonomethylbarium, monoacetoxymonoethylbarium, monoacetoxymonopropylbarium, monopropionyloxymonomethylbarium, monoacyloxymonoalkylbarium such as monopropionyloxymonoethylbarium, and monoacyloxymonoalkylbarium. Acetoxymonomethoxybarium, monoacetoxymonoethoxybarium, monoacetoxymonopropoxybarium, monopropionyloxymonomethoxybarium, monopropionyloxymonoethoxybarium and other monoacyloxymonoalkoxybariums, dimethylbarium, diethylbarium, dipropylbarium, etc. Alkyl bariums, dimethoxy barium, diethoxy barium, dipropoxy barium,
Barium alkoxides such as diproxybarium, monomethylmonoethoxybarium, monoethyl, monoproxybarium, monoalkylmonoalkoxybarium such as monobutylmonopentoxybarium, barium acetate, barium propionate, barium valerate, barium caproate, benzoin Examples thereof include barium carboxylates such as barium acid, barium acetylacetonate, and β-diketones of barium benzoylacetonate.

Specifically, as the Sr compound, monoacetoxymonomethylstrontium, monoacetoxymonoethylstrontium, monoacetoxymonopropylstrontium,
Monopropionyloxymonomethylstrontium, monoacyloxymonoalkylstrontium such as monopropionyloxymonoethylstrontium, monoacetoxymonomethoxystrontium, monoacetoxymonoethoxystrontium, monoacetoxymonopropoxystrontium, monopropionyloxymonomethoxystrontium, monopropionyloxymono Monoacyloxymonoalkoxy strontium such as ethoxy strontium, alkyl strontium such as dimethyl strontium, diethyl strontium, dipropyl strontium, dimethoxy strontium, etc.
Strontium alkoxides such as diethoxystrontium, dipropoxystrontium, and diptoxystrontium, monomethylmonoethoxystrontium,
Monoalkyl monoalkoxy strontium compounds such as monoethyl, monopropoxy strontium, monobutyl monopentoxy strontium, strontium acetate, strontium propionate, strontium valerate, strontium caproate, strontium carboxylate such as strontium benzoate, strontium acetylacetonate , Β-diketones of strontium benzoylacetonate, and the like.

Specifically as a Ca compound, monoacetoxy monomethyl calcium, monoacetoxy monoethyl calcium,
Monoacetoxy monopropyl calcium, moopropionyloxy monomethyl calcium, monopropionyloxy monoethyl calcium and other monoacyloxy monoalkyl calciums, monoacetoxy monomethoxy calcium, monoacetoxy monoethoxy calcium, monoacetoxy monopropoxy calcium, monopropionyloxy monomethoxy Calcium, monoacyloxymonoalkoxy calciums such as monopropionyloxymonoethoxy calcium, alkyl calciums such as dimethyl calcium, diethyl calcium, dipropyl calcium, calcium alkoxides such as dimethoxy calcium, diethoxy calcium, dipropoxy calcium, diptoxy calcium Class, monomethyl monoethoxy calcium, mono Chill, monoproxy calcium, monoalkyl monoalkoxy calciums such as monobutyl monopentoxy calcium, calcium acetate, calcium propionate, calcium valerate, calcium caproate, calcium carboxylates such as calcium benzoate, calcium acetylacetonate , Β-diketones of calcium benzoylacetonate, and the like.

A titanium compound soluble in an organic solvent is represented by the formula TiZ ₄ (wherein Z is an alkyl group, an alkoxy group, a halogen group,
At least one selected from an acyloxy group and a β-diketone group is shown. Although a compound represented by the formula (1) and / or a condensate thereof can be used, it is desirable that Z has 14 or less, preferably 8 or less carbon atoms.

If it exceeds 14, organic substances are likely to remain in the molded body after firing, and pores are easily formed, which may cause conduction or deteriorate dielectric properties.

Specifically, monoacetoxytrimethyltitanium,
Monoacetoxytriethyltitanium, monoacetoxytripropyltitanium, monopropionyloxytrimethyltitanium, monopropionyloxytriethyltitanium, and other monoacyloxytrialkyltitaniums, monoacetoxytrimethoxytitanium, monoacetoxytriethoxytitanium, monoacetoxytripropoxytitanium, mono Propionyloxytrimethoxytitanium, monoacyloxytrialkoxytitaniums such as monopropionyloxytriethoxytitanium, monoacetoxytrichlortitanium, monoacetoxytitanium halides such as monoacetoxytribromiumtitanium, diacetoxydimethyltitanium, dipropionyloxydiethyltitanium, Dibutyryloxydipropyi Diacyloxydialkyltitaniums such as titanium, diacetoxydimethoxytitanium, dipropionyloxydiethoxytitanium, dibutyloxydipropoxytitanium and other diacyloxydialkoxytitaniums, diacetoxydichlortitanium, diacetoxydibromtitanium and other diacyloxys. Dititanium halides, triacetoxymonomethyltitanium, tripropionyloxymonoethyltitanium, tributyryloxymonopropyltitanium and other triacyloxymonoalkyl titaniums, triacetoxymonomethoxytitanium, tripropionyloxymonoethoxytitanium, tributyloxymonopropoxy Titanium triacyloxymonoalkoxytitaniums, triacetoxy Triacyloxymonotitanium halides such as nochlortitanium and triacetoxymonobromotitanium, monoalkyltrialkoxytitaniums such as monomethyltriethoxytitanium, monopropyltributoxytitanium, monobutyltripentoxytitanium, dimethyldiethoxytitanium, di Dialkyldialkoxytitaniums such as propyldibutoxytitanium and dibutyldipentoxytitanium, trimethylmonoethoxytitanium,
Trialkylmonoalkoxytitaniums such as tripropylmonobutoxytitanium and tributylmonopentoxytitanium, monoalkyltrititanium halides such as monomethyltrichlorotitanium and monobutyltribromtitanium, dialkyl such as diethyldichlorotitanium and dibutyldibromtitanium. Dititanium halides, triethylmonochlorotitanium, trialkyl monotitanium halides such as tripentyl monobrom titanium, monoethoxy trichlorotitanium,
Monoalkoxytrititanium halides such as monobutoxytribromotitanium, dialkoxydititanium halides such as dimethoxydichlorotitanium, dipropoxydibromotitanium, etc., trialkoxymonotitanium such as tripropoxymonobromtitanium. Alkyl titaniums such as halides, tetramethyl titanium, tetraethyl titanium, etc., titanium alkoxides such as methyl titanate, ethyl titanate, propyl titanate, butyl titanate, octyl titanate, titanium halides such as titanium tetrachloride and titanium tetrabromide, Titanium acetate, titanium propionate, titanium valerate, titanium caproate, titanium benzoate, and other titanium carboxylates, titanium Pyridinium acetyl acetate, beta-diketones such as titanium benzoylacetonate toner preparative and such condensates thereof and the like.

Polytitanoxane, which is a condensate of titanium compounds, can be produced by condensing these acyloxyalkyltitanium, acyloxyalkoxytitanium, acyloxyhalogenated titanium, alkoxytitanium, alkoxytitanium, and the like as starting materials, or alkyltitanium, It can also be produced by reacting a polytitanoxane obtained by condensing an alkoxytitanium or a titanium halide with a carboxylic acid.

The organic solvent used in the practice of the present invention,
Any material may be used as long as it dissolves the lead compound, the alkaline earth metal compound and the titanium compound, but preferably alcohols such as methanol, ethanol, propanol, butanol and pentanol, benzene and toluene. , Aromatic hydrocarbons such as xylene, aliphatic hydrocarbons such as pentane, hexane, heptane, and octane, ethers such as dioxane and tetrahydrofuran, ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl acetate, ethyl acetate, Carboxylic esters such as ethyl formate, β-diketones such as acetylacetone, benzoylacetone and dibenzoylacetone,
Examples thereof include amides such as dimethylformamide and dimethylacetamide, and these solvents may be used alone or in combination of two or more kinds.

In carrying out the present invention, first, a dielectric forming solution is synthesized.As a method for synthesizing the dielectric forming solution, the lead compound as the raw material metal compound and the alkali metal compound are mixed in a molar ratio of Pb: M = 1-x: x (0.1 ≦ x ≦ 0.9), and further P
Examples include a method in which the titanium compound is mixed so that the molar ratio of b + M and Ti is 1: 1 and dissolved in an organic solvent at an appropriate ratio, or the raw material metal compound is reacted in the organic solvent.

The molar ratio x of the lead compound and the alkali metal compound is 0.1 to 0.
9, preferably in the range of 0.2 to 0.8.

When it is less than 0.1, the dielectric constant is low, and when it exceeds 0.9, the same is true, which is not preferable.

The concentration of the metal compound in the thin film dielectric forming solution used in the present invention varies depending on the kind of the metal compound, but if it is too diluted, it must be applied many times to obtain the target film thickness. It is not economical, and if it is too thick, the workability is deteriorated. Therefore, it is generally applied in an amount of 2 to 80% by weight, preferably 5 to 50% by weight in terms of oxide.

Normally, the concentration of the forming solution is determined by the desired thickness of the thin film dielectric.

Carboxylic acid C ₆ -C ₂₀ in order to stabilize the thickness of the dielectric forming solution used in the present invention, glycol, can be added to amine.

Specifically, monovalent carboxylic acids such as caproic acid, caprylic acid, capric acid, lauric acid, palmitic acid and stearic acid, divalent carboxylic acids such as adipic acid, pimelic acid, phthalic acid and sebacic acid, ethylene glycol and propylene. Glycols such as glycol and diethylene glycol,
Examples thereof include amines such as monoethanolamine, diethanolamine and triethanolamine.

0.1 to 3.0 mol of the above substance relative to Ti, preferably 0.1 to 3.0
It can be added in the range of 2.0 mol.

If it is less than 0.1 mol, the effect of stabilizing the film thickness is small, and if it exceeds 3.0 mol, it is difficult to obtain a dense and smooth film after firing because the organic substances increase.

In addition, Mg, Bi, Zr,
Compounds such as Nb, Ta, Nd, Sb, Mn, Al for reducing reduction,
A compound such as Si may be added.

Further, in order to make the thickness of the coating film uniform, for example, high molecular substances such as polyol and ethyl cellulose, high boiling point compounds such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, acetylacetone and glycerin, nonionic or anionic surface active agents. It is also possible to add agents and the like.

The dielectric-forming solution thus synthesized is then applied on a substrate and dried and baked to form a thin-film dielectric, or
Alternatively, coating and drying and firing are repeated several times to form a thin film dielectric having a desired thickness.

Any substrate can be used as long as it has a smoothness and can withstand a temperature of 400 ° C. or higher, for example, a glass substrate, a ceramic substrate, a metal thin film or a conductive oxide. Examples include glass or ceramic substrates coated with objects, metal plates, metal foils, semiconductor substrates, and the like.

Specifically, quartz glass, alumina, zirconia, mica, silicon, gold, platinum, palladium, silver, copper, chromium, aluminum, tantalum, gold-chromium, palladium-silver, nickel-chromium, zirconium or antimony-doped oxidation. Examples include quartz glass coated with a thin film of indium or the like, alumina, zirconia, mica, silicon, gold, platinum, palladium, silver, copper, nickel, nickel-chromium, or the like.

The surface of the substrate is desired to be as smooth as possible, and the surface roughness Ra <0.1 μ is preferable.

As a method of applying the coating liquid to the substrate, known application methods such as a dipping method, a spray method, a spinner method, and a brush coating method can be used.

The film thickness of the thin film can be controlled by the concentration of the coating solution, the pulling rate in the dipping method, the rotation speed of the spinner in the spinner method, and the like.

The heat treatment temperature of the coating film obtained by applying to the substrate varies depending on the concentration of the metal compound in the solvent, the type of the solvent, the type of the substrate, etc., but it is necessary to set the temperature above the crystallization of the dielectric, and it is usually about It is 400 to about 1200 ° C, preferably about 500 to about 1000 ° C.

If the temperature is lower than 400 ° C., the organic matter is not decomposed, and if the temperature is higher than 1200 ° C., the stoichiometry shifts due to evaporation of the Pb compound, etc., and it is difficult to obtain a dielectric having desired dielectric properties.

The firing atmosphere can be in air, in an inert gas, in a reducing atmosphere, or in an oxygen atmosphere if the dielectric substance is easily reduced.

The thickness of the thin film dielectric of the present invention is 0.1 to 10 μm, preferably 0.2 to 5 μm.

If it is less than 0.1 μm, the withstand voltage is low, and dielectric breakdown is likely to occur. If it exceeds 10 μm, the electrostatic capacity per layer becomes small, which makes it difficult to increase the capacity, which is not preferable.

<Effect of the Invention> The thin film dielectric of the present invention described in detail above is a thin film PbTi
O _3, the BaTiO _3, compared to the SrTiO ₃ accompanied as having excellent dielectric constant, which has good temperature characteristics, small order excellent in low withstand voltage dielectric loss, to mass capacitor Applicable.

In addition, the manufacturing method is low in manufacturing cost and capable of high capacity compared to the conventional method of making a dielectric powder into a slurry by a doctor blade method or the like, and it is possible to control the molar ratio as compared with the sputtering method or the like. Since it can be accurately performed, it is possible to provide a thin film dielectric having excellent dielectric properties, and its industrial value is extremely large. In the present invention, the measurement of electrical characteristics is JIS510.
2 Based on the test method for solid capacitors for electronic equipment.

<Examples> Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

Example 1 Lead isopropoxide, barium isopropoxide, and titanium isopropoxide were mixed in a ratio as shown in Table 1, and 1: 1 by weight of isopropanol-toluene (weight ratio).
Dissolved in mixed solvent, isostearic acid to Ti 0.
By adding 2 mol, 20 wt% of a dielectric forming liquid in terms of oxide was synthesized.

This solution was applied from a spinner on an alumina substrate coated with an Au / Cr (0.6 / 0.05 μm) film under the condition of 2000 revolutions.
Perform baking at 0 ° C for 30 minutes in oxygen, and perform the above coating and baking 4
Repeated times and finally baked at 800 ° C. for 1 hour in oxygen to obtain a dense and transparent thin film dielectric having a thickness of 1.0 μm.

After forming an Au electrode on this film by sputtering, 1KH
The relative permittivity and dielectric loss at z and 25 ° C were measured by Yokogawa Hewlett-Packard LCR meter 4262A.

Further, the temperature coefficient of capacitance was measured by the LCR meter after inserting the sample into a constant temperature bath in the range of 25 to 125 ° C.

 A withstand voltage was measured by applying a DC voltage.

 Table 1 shows the results.

As a result of X-ray diffraction of the obtained thin film shaped product, it was confirmed to be a thin film having a structure equivalent to the raw material adjusted composition.

* In the table, x means x of Pb: Ba = 1-x: x.

Further, R in the sample No. means a comparative example. (The same applies hereinafter) Example 2 Lead ethoxide, strontium isopropoxide, and titanium butoxide were mixed in the proportions shown in Table 2, dissolved in methylcellosolve solvent, and diethanolamine was added in an amount of 1.5 mol with respect to Ti. A dielectric forming liquid of 15% by weight in terms of oxide was synthesized.

This solution was placed on a silicon substrate coated with a Pt / Ni film for 4000r.
After coating with a spinner at 450 ° C. for 30 minutes under the pm rotation condition, baking in oxygen is performed, and the above coating baking is repeated 8 times, and finally baking is performed at 800 ° C. for 1 hour in oxygen to obtain a dense film with a thickness of 2.0 μm. A transparent thin film dielectric was obtained.

The electrical characteristics of this thin film were measured by the same method as in Example 1.

 The results are shown in Table 2.

Example 3 Lead butoxide 21.2 g and calcium ethoxyside 5.2
g and titanium ethoxide 13.8 g with Pb: Ca = 0.6: 0.4, Pb
+ Ca / Ti = 1 was prepared, dissolved in an isopropanol solvent, and 1.0 mol of 2-ethylhexanoic acid was added to Ti to synthesize a dielectric-forming liquid of 10% by weight in terms of oxide.

5000r of this liquid on a quartz glass substrate coated with an ITO film
After coating with a spinner under the pm rotation condition, baking is performed in air at 450 ° C for 30 minutes, and the same operation is repeated 5 times. Finally, baking is performed at 900 ° C for 1 hour in air to obtain a dense film with a thickness of 1.5 μm. To obtain a transparent thin film dielectric.

When the electrical characteristics of this thin film were measured by the same method as in Example 1, the relative dielectric constant: 490, the dielectric loss: 0.01, the temperature coefficient: 600 ppm.
The characteristics of / ° C and withstand voltage: 15 were obtained.

Example 4 12.33 g of lead 2-ethylhexanoate, 8.38 g of barium acetylacetonate and 6.9 g of titanium ethoxide were dissolved in a toluene solvent (Pb / Ba = 1Pb + Ba / Ti = 1), and 30% by weight in terms of oxide. The dielectric forming liquid of was synthesized.

This solution was applied on an alumina substrate coated with a Pt / Ni film by adjusting the rotation speed with a spinner so that the film thickness after firing would be as shown in Table 3, and then 900 ° C x 1 hour, A thin film dielectric was obtained by firing in air.

The electrical characteristics of this thin film were measured by the same method as in Example 1.

 The results are shown in Table 3.

Example 5 28.4 g of titanium toteraisopropoxide was dissolved in isopropanol, and 1.8 g of distilled water was added dropwise thereto,
Polytitanoxane was synthesized.

Next, 22.75 g of lead acetate and 6.15 g of strontium isopropoxide were mixed in the polytitanoxane solution, and (Pb: Sr =
0.7: 0.3, Pb + Sr / T, isostearic acid (for Ti
0.5 mol / Ti = 1) was added to synthesize a dielectric forming liquid of 15% by weight in terms of oxide.

This solution was coated on a platinum plate with a spinner under the conditions of 4000 rpm and baked in oxygen at 450 ° C for 30 minutes, and the same operation was repeated 3 times, and finally in air at 800 ° C for 1 hour. As a result, a dense thin film dielectric having a film thickness of 0.8 μm was obtained.

When the electrical characteristics of this thin film were measured by the same method as in Example 1, the relative permittivity was 820, the dielectric loss was 0.018, and the temperature coefficient was 600 pp.
The characteristics of m / ° C and withstand voltage: 10 were obtained.

Example 6 16.25 g of lead isopropoxide, 8.85 g of strontium ethoxide and 19.0 g of titanium tetrachloride were mixed in an isopropanol solvent, Pb: Sr = 1: 1, Pb + Sr / Ti = 1), and diethanolamine was added to Ti. 1.5 mol / Ti was added to synthesize a dielectric forming liquid of 20% by weight in terms of oxide.

This solution was placed on an alumina substrate coated with a Pb / Ni film at 4000r.
After coating with a spinner at 450 ℃ x 30 minutes under the condition of pm, baking in air is repeated, and the same operation is repeated 5 times, and finally baked at 800 ℃ x 1 Hr, in air to obtain a dense film thickness of 1.5 μm. A thin film dielectric was obtained.

The electrical characteristics of this thin film were measured in the same manner as in Example 1, and the relative permittivity was 690, the dielectric loss was 0.015, and the temperature coefficient was 650 pp.
The characteristics of m / ° C and withstand voltage: 15V were obtained.

Example 7 Strontium acetylacetonate, titanium butoxide and a Pb compound as shown in Table 4 were mixed,
(Pb: Sr = 1: 1, Pb + Sr / Ti = 1) was dissolved in a toluene solvent to synthesize a dielectric-forming liquid of 10% by weight in terms of oxide.

This solution was applied on a strontium titanate single crystal substrate coated with a Pt / Ni film by a spinner under the condition of 4000 rpm, then baked at 450 ° C for 30 minutes in the air, and the same operation was repeated twice, and finally Firing was performed in air at 800 ° C. for 1 hour to obtain a thin film dielectric having a film thickness of 0.5 μm.

The electrical characteristics of this thin film were measured by the same method as in Example 1.

 The results are shown in Table 4.

Example 8 Lead ethoxide 29.78 and barium isopropoxide 25.7 g
And titanium isopropoxide 56.8g were dissolved in isopropanol solvent (Pb: Ba = 0.4: 0.6, Pb + Ba / Ti =
1) Further, 5.4 g of distilled water (1.5 mol with respect to Ti) was added dropwise in nitrogen at a reaction temperature of 50 ° C., and the mixture was refluxed for 2 hours to synthesize a dielectric-forming liquid of 10% by weight in terms of oxide.

This solution was placed on an alumina substrate coated with a Pt / Cr film at 3000r.
After coating with a spinner at 450 pm x 30 minutes under the condition of pm, bake in oxygen and repeat the same operation twice to finally 900
Dense and transparent film thickness 1.0 μm after baking in oxygen for 1 hour at ℃
A thin film dielectric of

When the electrical characteristics of this thin film were measured by the same method as in Example 1, the relative dielectric constant: 500, the dielectric loss: 0.011, the temperature coefficient: 400 pp
The characteristics of m / ° C and withstand voltage: 15 were obtained.

Comparative Example 1 32.5 g of lead isopropoxide and 28.4 g of titanium isopropoxide were mixed at a ratio of Pb / Ti = 1.0, and dissolved in a 1: 1 (weight ratio) mixed solvent of isopropanoltoluene to convert isostearic acid to Ti. On the other hand, 0.2 mol was added to synthesize a dielectric-forming solution of 15% by weight in terms of oxide.

After applying this solution to the alumina substrate field coated with Au / Cr (0.6 / 0.05 μm) film by spinner at 2000 rpm
The film was baked in oxygen at 450 ° C. for 30 minutes, and the above-mentioned coating and baking was repeated four times. Finally, the film was baked in oxygen for 800 × 1 Hr to obtain a thin film dielectric having a thickness of 1.0 μm.

The electrical characteristics of this thin film were measured by the same method as in Example 1. Table 5 shows the results.

Comparative Example 2 5.1 g of barium isopropoxide and 6.8 g of titanium putoxide were dissolved and mixed in a methylcellosolve solvent at a ratio of Ba / Ti = 1.0, and 1.5 mol of diethanolamine was added to Ti to obtain 15% by weight as oxide. The dielectric forming liquid of was synthesized.

This solution was placed on a silicon substrate coated with a Pt / Ni film for 4000r.
After coating with a spinner under the pm rotation condition, baking is performed at 450 ° C for 30 minutes in oxygen and the above coating baking is repeated 6 times, and finally at 800 ° C for 1 hour, baking in oxygen to obtain a film thickness of 1.2 μm.
A thin film dielectric of

The electrical characteristics of this thin film were measured by the same method as in Example 1. Table 5 shows the results.

Comparative Example 3 Strontium ethoxyside (17.8 g) and titanium ethoxide (22.8 g) were dissolved in an isopropanol solvent at a ratio of Sr / Ti = 1.0, and 2 ethylhexanoic acid was added to Ti.
0 mol was added to synthesize a dielectric-forming liquid of 10% by weight in terms of oxide.

5000r of this liquid on a quartz glass substrate coated with an ITO film
After coating with a spinner under the pm rotation condition, baking is performed in air at 450 ° C for 30 minutes, the same operation is repeated 5 times, and finally baking is performed at 900 ° C for 1 hour in air to obtain a film thickness of 1.5μ. A thin film dielectric of

The electrical characteristics of this thin film were measured by the same method as in Example 1. Table 5 shows the results.

Comparative Example 4 7.9 g of calcium isopropoxide and 11.4 g of titanium ethoxide were dissolved in a toluene solvent (Ca / Ti = 1.
0), and 10% by weight of oxide as a dielectric forming liquid was synthesized.

0.5 μm of this solution on an alumina substrate coated with a Pt / Ni film.
The number of revolutions was adjusted by a spinner so that the film thickness became m, and after coating, it was baked in air at 900 ° C. for 1 hour to obtain a thin film dielectric.

The electrical characteristics of this thin film were measured by the same method as in Example 1. Table 5 shows the results.

Comparative Example 5 8.4 g of lead acetate, 0.859 g of lanthanum isopropoxide, 2.84 g of titanium isopropoxide and 6.082 g of zirconium isopropoxide were added to Pb: La = 0.905: 0.095, Ti: Zr = 0.35: 06.
5, (Pb + La) / (Ti + Zr) = 1.0 was mixed and dissolved in a 1: 1 (weight ratio) mixed solvent of isopropanoltoluene to synthesize a 15% by weight dielectric forming solution.

This solution was coated on a platinum substrate with a spinner under the condition of 2000 rotations, and then baked in oxygen at 450 ° C for 30 minutes, and the above coating and baking was repeated 4 times, and finally baked at 800 ° C for 1 hour in oxygen. Thus, a thin film dielectric having a film thickness of 1.0 μm was obtained.

The electrical characteristics of this thin film were measured by the same method as in Example 1. Table 5 shows the results.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H01L 21/316 C04B 35/46 H (56) References JP-A-55-10448 (JP, A) JP-A-52-1499 (JP, A) JP-A-60-236404 (JP, A)

Claims (2)

(57) [Claims] 1. An average film thickness of 0.1 μm represented by a composition formula (Pb _1-x M _x ) TiO ₃ (wherein 0.1 ≦ x ≦ 0.9, M represents one or more of alkaline earth metals). ~ 10μ
m, relative permittivity of 300 or more, temperature coefficient of capacitance −1000 ppm /
Thin film dielectric with physical properties of ℃ ~ + 1000ppm / ℃. 2. A lead compound, an alkaline earth metal compound, and a titanium compound which are soluble in an organic solvent are dissolved or reacted in the organic solvent to synthesize a dielectric-forming solution, and then the solution is applied onto a smooth substrate. To form a thin film and heat-treat the thin film, or repeatedly apply the solution to the substrate and heat-treat it to obtain a compositional formula (Pb _1-x M _x ) TiO ₃ (equation of 0.1 μm to 10 μm). In the formula, 0.1 ≦ x ≦ 0.9, M represents one or more of alkaline earth metals), and a thin film is formed with a metal oxide represented by the formula).