JP3421077B2 - Method of forming functional thin film - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming another functional thin film on an oxide base material such as glass or ceramics, which is capable of newly coating the characteristics of the base material. The present invention relates to a method for forming a functional thin film capable of imparting characteristics. More specifically, the function of forming an oxide thin film whose main component is represented by the composition formula BOy on the surface of an oxide base material whose main component is represented by the composition formula AOx via a bonding layer of AOB. Method of forming a conductive thin film.

[0002]

2. Description of the Related Art Conventionally, as a method of coating an oxide base material with other metal oxides as described above, a CVD method for forming a thin film from a gas phase or a method of immersing a base material in a metal alkoxide solution for hydrolysis A so-called sol-gel method for forming a thin film of a metal oxide by baking and a sputtering method for forming a thin film by physically colliding a molecular mass (cluster) with a substrate are known.

[0003]

However, among the above-mentioned conventional methods, in the CVD method and the sol-gel method, a bonding layer of A-O-B is formed between the base material and the thin film to improve the adhesion of the thin film. In that case, a high temperature exceeding 600 ° C. is required. This is because this reaction is due to a dehydration condensation reaction between the A-OH group on the surface of the base material and the B-OH group on the thin film, and this condensation reaction generally causes the degree of freedom of the -OH group to increase to 600 ° C. It is said that it will happen when it exceeds. For this reason,
It is impossible to form a thin film on A-glass, C-glass, E-glass, etc., which have high versatility, and there is a disadvantage that the substrate to be coated is limited. On the other hand, the sputtering method is a method of forming a thin film by colliding a metal oxide with a base material in units of clusters of molecules, so that the collision energy causes the A—O—B bond at a relatively low temperature as compared with other methods. Can be formed. However, since the film is formed only on one surface facing the target, it is difficult to form a uniform film on a complicated shape, for example, a textile product such as a woven cloth or a nonwoven cloth, or a powder or granular material. The present invention solves these drawbacks of the conventional method and forms a strong functional thin film on various oxide base materials whose main components are represented by the composition formula AOx via a bonding layer of AOB. The purpose is to provide a way to.

[0004]

In order to solve the drawbacks of the conventional method, the inventors of the present invention have compatibility with a precursor of a metal oxide represented by the composition formula BOy by heating and an organic resin. In the solution formed by dissolving in the solvent, the main component is the composition formula A
The inventors have found that the problems of the conventional method can be solved by immersing the oxide base material represented by Ox, followed by drying and firing, and completed the present invention. That is, the method for forming a functional thin film of the present invention is a method of forming a functional thin film in which the main component is an oxide thin film represented by the composition formula BOy on the surface of an oxide substrate represented by the composition formula AOx. A method of forming the composition formula AO
A of x is any element selected from Si, Al, Ti, Zr and B, and B of the composition formula BOy is A
l, Si, Ti, V, Cr, Mn, Fe, Co, Ni,
It is any element selected from Cu, Zr, and Mo, and these A and B are elements of different types, and the oxide base material is heated to become an oxide represented by the composition formula BOy. 200 ° C. after being immersed in a solution prepared by dissolving an oxide precursor and an organic resin in a compatible solvent and drying.
In the temperature rising / calcination process up to ~ 600 ° C, the temperature is gradually increased to the baking temperature and the temperature is increased by baking, whereby the organic resin and the organic residue constituting the oxide precursor are oxidized and decomposed. The generated combustion heat causes a dehydration condensation reaction between the A-OH group on the surface of the base material and the B-OH group of the thin film, and A-O is generated between the oxide base material and the oxide thin film. And forming a bonding layer of -B to form the oxide thin film.

Examples of the oxide base material represented by the composition formula AOx include glass and ceramics, and A may be an oxide of an element such as Si, Al, Ti, Zr or B. Further, the shape of the oxide base material is plate-like, fibrous,
Any shape, such as powder, can be used.

In the oxide represented by the composition formula BOy, B is Al, Si, Ti, V, Cr, Mn, Fe, C.
Examples thereof include oxides containing elements such as o, Ni, Cu, Zr, and Mo. Examples of the precursor that becomes an oxide represented by the composition formula BOy by heating include metal alkoxides, metal chlorides, and metal sulfides. , Metal acetic acid and the like can be used, but from the viewpoint of compatibility with organic resins, it is preferable to select a metal alkoxide when alcohols are a compatible solvent, and a metal chloride when water is a compatible solvent. . But,
When the metal oxide precursor and the organic resin are compatible with each other, any combination may be selected.

The organic resin is generally an acrylic resin, an olefin resin, or the like, but since it needs to undergo oxidative decomposition in the firing step during the forming step, it is a resin whose decomposition temperature is 200 ° C. or higher and lower than or equal to the firing temperature. Further, it is only necessary that it is compatible with the metal oxide precursor, and is not particularly limited depending on the kind and molecular weight of the monomer.

The oxide base material is dipped in a solution of the organic resin and the metal oxide precursor thus selected, and then dried. The drying temperature varies depending on the boiling point of the compatible solvent, but is preferably in the range of 40 to 150 ° C. next,
By baking the dried film, the organic residues constituting the precursor of the organic resin or the metal oxide are removed. The firing temperature is preferably in the range of 200 ° C to 600 ° C. By this firing, the metal oxide precursor is changed to a metal oxide, and the organic resin is oxidatively decomposed to obtain a thin film having an A-O-B bond.

[0009]

In the present invention, the formation of the A--O--B bond is due to the dehydration condensation reaction between the A--OH group on the surface of the substrate and the B--OH group of the thin film, and the conventional CVD method or It is similar to the sol-gel method. However, in the present invention, the dehydration condensation reaction proceeds due to the heat of combustion generated by the oxidative decomposition reaction of the organic residue that constitutes the precursor of the organic resin and the metal oxide, and the A—O—B bond at a relatively low temperature. Is formed. Therefore, even when a base material such as glass having low heat resistance is used, it is possible to form a thin film having a layer having an A-O-B bond.

[0010]

EXAMPLES Next, more specific examples will be described together with comparative examples. If the oxide base material, the precursor material of the metal oxide, and the organic resin satisfy the above conditions, the same effect is obtained. Therefore, as a typical example, an A glass substrate (main component SiO ₂ ) and a metal oxide (main component Ti) are used as oxide base materials.
A combination of titanium isopropoxide as a precursor of O ₂ ), an acrylic resin (decomposition temperature of 350 ° C.) as an organic resin, and ethyl alcohol as a compatibilizer will be selected and described.

(Example) A glass substrate was immersed in a solution prepared by dissolving 10 g of titanium isopropoxide as a metal oxide precursor and 10 g of an acrylic resin in 180 g of ethyl alcohol. Remove this substrate from the solution and
After drying for 1 hour, the temperature was raised to 450 ° C at a rate of 1 ° C / min and kept at 450 ° C for 5 hours to completely oxidize and decompose the organic resin, and at the same time convert titanium isopropoxide into an oxide of TiO _2. Change and TiO on A glass substrate
_Two films were formed. At this time, the thickness of the TiO ₂ film is about 0.3.
It was μm and was firmly attached. About this film EP
MA (X-ray microanalyzer for measurement, JEM-2000FXII made by JEOL Ltd.) and ESCA (X-ray photoelectron spectrometer for measurement, XSAM made by Shimadzu Kraitos)
800) was used to analyze Si-O-
The presence of Ti bond was confirmed. FIG. 1 is a cross-sectional view of a thin film formed by this example, 1 is an A glass substrate, 2 is
Indicates a TiO ₂ thin film, and 3 indicates a Si—O—Ti bonding layer.

COMPARATIVE EXAMPLE 1 The same A as that used in the example
An attempt was made to form a TiO ₂ thin film by a CVD method using a glass substrate as a base material and a reaction temperature of 450 ° C. and using titanium tetrachloride. As a result, a uniform TiO ₂ thin film was not formed on the A glass substrate, and powdery TiO ₂ was deposited. FIG. 2 is a cross-sectional view of the TiO ₂ powder and the A glass substrate formed in Comparative Example 1, where 1 is the A glass substrate and 4 is the TiO ₂ powder deposited on the A glass substrate.

(Comparative Example 2) A same as that used in Example
Using a glass substrate as a base material, an attempt was made to form a TiO ₂ thin film by the sol-gel method. A method similar to that of the example was applied except that the liquid for immersing the glass substrate A was changed to a solution in which 10 g of titanium isopropoxide, 0.1 g of concentrated hydrochloric acid and 190 g of ethyl alcohol were changed. As a result, the formed TiO ₂
The thickness of the film was about 0.3 μm, but it peeled off easily due to weak adhesion. When this film was analyzed by EPMA and ESCA, the presence of Si—O—Ti bonds was not confirmed. FIG. 3 is a cross-sectional view of a thin film formed by Comparative Example 2, where 1 is an A glass substrate and 2 is a TiO ₂ thin film.

[0014]

As described above, according to the present invention, a strong film can be formed because the bonding layer of AOB is provided between the oxide base material and the oxide thin film. Moreover, such a bonding layer of A-O-B can be formed at a relatively low temperature. In addition, it has an effect that it can be widely applied to applications such as heat-resistant materials, catalysts, and catalyst carriers according to the characteristics of the oxide thin film to be formed.

[Brief description of drawings]

FIG. 1 is a sectional view of a functional thin film obtained by an example.

FIG. 2 is a sectional view of a functional thin film obtained in Comparative Example 1.

FIG. 3 is a sectional view of a functional thin film obtained in Comparative Example 2.

[Explanation of symbols]

1 A glass substrate 2 TiO ₂ thin film 3 Si-O-Ti bonding layer 4 TiO ₂ powder

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-57-74366 (JP, A) JP-A-62-297470 (JP, A) JP-A-49-54422 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C04B 41/80-41/91

Claims (2)

(57) [Claims] 1. A method of forming a functional thin film, the method comprising forming an oxide thin film whose main component is represented by composition formula BOy on the surface of an oxide base material whose main component is represented by composition formula AOx. A in the formula AOx is any element selected from Si, Al, Ti, Zr, and B, and B in the composition formula BOy is Al, Si, Ti, V, Cr, Mn, Fe, Co, N
An oxide represented by the composition formula BOy, which is any element selected from i, Cu, Zr, and Mo, wherein A and B are different types of elements, and the oxide base material is heated to heat. immersed in a solution obtained by dissolving the oxide precursor and an organic resin comprising a solvent having compatibility, dried, 200
In the temperature rising / calcination process from 0 ° C to 600 ° C, the oxidative decomposition reaction of the organic residue constituting the organic resin and the oxide precursor is performed by gradually increasing the temperature to the calcination temperature and calcination. The heat of combustion generated by the reaction causes a dehydration condensation reaction between the A-OH group on the surface of the base material and the B-OH group on the thin film, and A-OH between the oxide base material and the oxide thin film. A method of forming a functional thin film, which comprises forming a bonding layer of OB to form the oxide thin film. 2. The method for forming a functional thin film according to claim 1 , wherein the organic resin is a resin having a decomposition temperature of 200 ° C. or higher and a firing temperature or lower.