JP2009120874A - Method for producing metal oxide film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a metal oxide film which can obtain a metal oxide film having low crystallinity. <P>SOLUTION: In the method for producing a metal oxide film where a solution for forming a metal oxide film in which, as a metal source, a metal salt or an organometallic compound is dissolved is contacted with a base material heated to a temperature more than a metal oxide film forming temperature, so as to obtain a metal oxide film on the base material, the solution for forming a metal oxide film comprises a boron compound reducing the crystallinity of the metal oxide film. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a method of manufacturing a metal oxide film that can obtain a metal oxide film having low crystallinity.

  Conventionally, it has been known that metal oxide films exhibit various excellent physical properties. Taking advantage of these properties, metal oxide films have been used in a wide range of fields such as transparent conductive films, optical thin films, and fuel cell electrolytes. As a method for producing such a metal oxide film, for example, a sol-gel method, a sputtering method, a CVD method, a PVD method, a printing method, a laser ablation method and the like are known (for example, Patent Documents 1 to 3).

  On the other hand, a spray pyrolysis method has been proposed as another method for obtaining such a metal oxide film. The spray pyrolysis method is a method in which a metal oxide film is obtained by spraying a solution containing a metal source constituting the metal oxide film onto a high temperature substrate, and a substrate heated to about 500 ° C. is usually used. Since it is used, the solvent instantly evaporates and the metal source undergoes a thermal decomposition reaction, so that the metal oxide film can be obtained in a short and simplified process.

As a study of such spray pyrolysis method, for example, in Patent Document 4, a raw material solution is prepared by adding hydrogen peroxide or aluminum acetylacetonate to a solution containing a TiO ₂ precursor, and the temperature is as high as about 500 ° C. A method is disclosed in which a TiO ₂ precursor is thermally decomposed into TiO ₂ by intermittently spraying the raw material solution onto a held substrate to obtain a porous TiO ₂ thin film on the substrate. Further, for example, Patent Document 5 is a method of obtaining a porous TiO ₂ thin film by a pyrolysis spray method as in Patent Document 4, but by adding a solution obtained by adding a soluble titanium compound to a raw material solution, TiO ₂ is obtained. ₍₂₎ The adhesion between the thin film and the substrate was improved.

  Although the spray pyrolysis method is a method capable of obtaining a metal oxide film in a short time and a simplified process, the crystallinity of the obtained metal oxide film depends on the type of the metal source of the material, etc. For this reason, a metal oxide film having desired crystallinity cannot be obtained in some cases. Specifically, if the crystallinity of the metal oxide film is too high, for example, there is a problem that the adhesion between the metal oxide film and the substrate is poor. In addition, when a highly crystalline metal oxide film is formed on a porous substrate, there is a problem that grain boundaries occur at the interface between the porous substrate and the metal oxide film, and the shape of the porous substrate There was a problem that it was difficult to obtain a metal oxide film that followed. Therefore, a method capable of obtaining a metal oxide film having low crystallinity has been desired.

  Patent Document 6 discloses a method for producing a metal oxide film by a sol-gel method, and discloses that a boron fluoride complex salt is used as a metal source. However, this technique is intended to improve the crystallinity of the metal oxide film, and is not intended to reduce the crystallinity of the metal oxide film as described above.

JP 2002-348665 A JP-A-4-361239 JP-A-2005-213105 JP 2002-145615 A JP 2003-176130 A JP-A-8-183605

  This invention is made | formed in view of the said situation, and it aims at providing the manufacturing method of the metal oxide film which can obtain a metal oxide film with low crystallinity.

  In order to solve the above problems, in the present invention, a metal oxide film forming solution in which a metal salt or an organometallic compound is dissolved as a metal source is contacted with a substrate heated to a temperature equal to or higher than the metal oxide film forming temperature. A metal oxide film manufacturing method for obtaining a metal oxide film on the base material, wherein the metal oxide film forming solution contains a boron compound that reduces the crystallinity of the metal oxide film A method for producing a metal oxide film is provided.

  According to the present invention, by adding a boron compound to a metal oxide film forming solution, compared to a metal oxide film obtained using a metal oxide film forming solution to which no boron compound is added. A metal oxide film having low crystallinity can be obtained.

  In the said invention, it is preferable that the said boron compound is a boric acid. This is because the crystallinity of the metal oxide film can be reduced more effectively.

  In the said invention, it is preferable that the said base material is a base material provided with the porous base material or the porous membrane. When the surface on which the metal oxide film is formed is porous, the metal oxide crystals are likely to grow from specific points on the porous surface, and grain boundaries are generated at the interface between the substrate and the metal oxide film. However, the electron conductivity and the adhesion are liable to decrease. Even in such a case, in the present invention, by adding a boron compound to the metal oxide film forming solution, the crystallinity of the metal oxide film can be reduced, and the generation of grain boundaries is suppressed. can do.

  In the said invention, it is preferable that the said solution for metal oxide film formation contains a doping metal source further. This is because a functional oxide film can be obtained by using a doping metal source.

  In the above invention, the metal element constituting the metal source is Mg, Al, Si, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Ag, In, Sn, Ce, Sm. Pb, La, Hf, Sc, Gd, Ca, Cr, Ga, Sr, Nb, Mo, Pd, Sb, Te, Ba, W, or Ta are preferable. This is because metal oxide films useful for various applications can be obtained.

  Further, in the present invention, the boron compound is a crystallinity reducing material which is added to a metal oxide film forming solution in which a metal salt or an organometallic compound is dissolved as a metal source, and which decreases the crystallinity of the metal oxide film. The crystallinity-reducing material is provided.

  According to the present invention, the crystallinity of a metal oxide film can be reduced by adding a boron compound to a metal oxide film forming solution containing a metal source.

  According to the present invention, there is provided a metal oxide film-forming solution characterized by containing a boron compound that dissolves a metal salt or an organometallic compound as a metal source and lowers the crystallinity of the metal oxide film. provide.

  According to the present invention, a metal oxide film having low crystallinity can be obtained by using a metal oxide film forming solution to which a boron compound is added.

  In the present invention, there is an effect that a metal oxide film having low crystallinity can be easily formed.

  The metal oxide film production method, crystallinity reducing material, and metal oxide film forming solution of the present invention will be described below.

A. First, a method for producing a metal oxide film of the present invention will be described. In the method for producing a metal oxide film of the present invention, a metal oxide film forming solution in which a metal salt or an organometallic compound is dissolved as a metal source is brought into contact with a substrate heated to a temperature equal to or higher than the metal oxide film forming temperature. By this, it is a manufacturing method of the metal oxide film which obtains a metal oxide film on the said base material, Comprising: The said solution for metal oxide film formation contains the boron compound which reduces the crystallinity of a metal oxide film It is characterized by this.

  According to the present invention, by adding a boron compound to a metal oxide film forming solution, compared to a metal oxide film obtained using a metal oxide film forming solution to which no boron compound is added. A metal oxide film having low crystallinity can be obtained. That is, the crystallinity of the metal oxide film can be easily reduced by adding the boron compound to the metal oxide film forming solution. The reason why the crystallinity of the metal oxide film is lowered is not necessarily clear, but when the metal oxide film is about to grow, boron components that do not contribute to the film-forming reaction on the surface of the metal oxide film are 300 ° C. or higher. It is expected that the phenomenon that boron oxide is discharged out of the reaction system is continuously generated, and as a result, the crystal growth of the metal oxide film is inhibited.

  Conventionally, when a porous substrate is used as the substrate, the metal oxide crystal is likely to grow from a specific point on the porous surface, and a grain boundary is generated at the interface between the substrate and the metal oxide film. There was a problem that the electron conductivity and the adhesiveness deteriorated. On the other hand, in the present invention, by adding a boron compound to the metal oxide film forming solution, it is possible to reduce the crystallinity of the metal oxide film and suppress the generation of grain boundaries. Have.

  Moreover, as an advantage of reducing the crystallinity of the obtained metal oxide film, for example, when the metal oxide film is used as a gas barrier layer, the barrier property can be improved. Further, by reducing the crystallinity of the metal oxide film, the adhesion between the base material and the metal oxide film can be improved. In particular, in the present invention, even when a porous substrate is used as the substrate, it is possible to obtain a metal oxide film excellent in adhesion and unevenness followability. The metal oxide film thus obtained can be used as, for example, a NOx gas processing cell or an oxygen-enriched film.

  Next, the manufacturing method of the metal oxide film of this invention is demonstrated using figures. FIG. 1 is an explanatory view showing an example of a method for producing a metal oxide film of the present invention. As shown in FIG. 1, the metal oxide film manufacturing method of the present invention heats the substrate 1 to a temperature equal to or higher than the metal oxide film forming temperature, and then contains a metal source and a boron compound. This is a method of forming a metal oxide film on the substrate 1 by spraying the forming solution 2 using the spray device 3.

  In the present invention, the “metal oxide film formation temperature” refers to a temperature at which a metal element contained in a metal source can combine with oxygen and form a metal oxide film on a substrate. It varies greatly depending on the type of metal source such as salt and organometallic compound and the composition of the metal oxide film forming solution such as solvent. In the present invention, such “metal oxide film formation temperature” can be measured by the following method. That is, the lowest base material on which a metal oxide film can be formed by preparing a solution for forming a metal oxide film that actually contains a desired metal source and changing the heating temperature of the base material to make contact Measure the heating temperature. This minimum substrate heating temperature can be set as the “metal oxide film forming temperature” in the present invention. At this time, whether or not the metal oxide film is formed is usually judged from the result obtained from an X-ray diffraction apparatus (Rigaku, RINT-1500). In the case of an amorphous film having no crystallinity, photoelectron spectroscopy is performed. It shall judge from the result obtained from the analyzer (the product made by VG Scientific, ESCALAB 200i-XL).

As described above, the metal oxide film formation temperature varies depending on the type of the metal source used, but is usually in the range of 200 to 600 ° C. In the present invention, the heating temperature of the substrate is not particularly limited as long as the temperature is higher than the metal oxide film formation temperature. For example, the metal oxide film formation temperature + 300 ° C. It is preferable that the film formation temperature + 200 ° C. or lower, particularly the metal oxide film formation temperature + 100 ° C. or lower. The heating temperature of the substrate is usually in the range of 300 to 600 ° C.
Hereafter, the manufacturing method of the metal oxide film of this invention is demonstrated in detail for every structure.

1. Metal Oxide Film Forming Solution First, the metal oxide film forming solution used in the present invention will be described. The metal oxide film forming solution used in the present invention contains at least a metal source and a boron compound. Furthermore, you may contain an oxidizing agent, a reducing agent, an additive, etc. as needed.

(1) Metal source First, the metal source used in the present invention will be described. The metal source used in the present invention is usually a metal salt or an organometallic compound. In the present invention, two or more kinds of metal sources may be used in combination.

In the present invention, the metal source is preferably a metal source capable of forming a single film by itself. Here, the “metal source capable of forming a single film” refers to a metal source that provides a metal oxide film that satisfies a predetermined standard in the following test. That is, a metal oxide film forming solution (concentration: 0.1 mol / l) comprising one target metal source and a solvent (for example, ethanol, toluene, or acetylacetone is preferably used) is prepared. The oxide film forming solution was made into droplets having a particle size of about 0.5 to 20 μm using an ultrasonic neplyzer or the like, and heated within the range of the metal oxide film forming temperature to the metal oxide film forming temperature + 100 ° C. A metal oxide film is formed on the substrate by contacting with the material for 1 hour, and then the obtained metal oxide film is cooled to room temperature, and the region of the metal oxide film of about 1 cm ^{2 is} subjected to a pressure of 0. A test of wiping with a waste cloth at about 2 Pa is performed. As a result, a metal source that provides a metal oxide film having a strength that does not cause peeling is referred to as a “metal source capable of forming a single film” in the present invention. In addition, as a base material, what is used when forming a metal oxide film actually is used. In addition, when the obtained metal oxide film is a powder, the metal oxide film does not correspond to a metal source capable of forming a single film because it easily peels off when wiped with a waste cloth.

  The metal element constituting the metal source is not particularly limited as long as a metal oxide film can be formed. For example, Mg, Al, Si, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Ag, In, Sn, Ce, Sm, Pb, La, Hf, Sc, Gd, Ca, Cr, Ga, Sr, Nb, Mo, Pd, Sb, Te, Ba, W, Ta, etc. can be mentioned, and Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, In, Sn, Ce, and La are particularly preferable.

  The metal salt is not particularly limited as long as it can form a metal oxide film. For example, chlorides, nitrates, sulfates, perchlorates, acetates containing the above metal elements, A phosphate, a bromate, etc. can be mentioned. Among these, in the present invention, it is preferable to use chloride, nitrate, and acetate. This is because these compounds are easily available as general-purpose products. Specific examples of the metal salt include magnesium chloride, aluminum nitrate, aluminum chloride, calcium chloride, scandium acetate, titanium tetrachloride, vanadium oxosulfate, ammonium chromate, chromium chloride, ammonium dichromate, chromium acetate, chromium nitrate. , Chromium sulfate, manganese acetate, manganese nitrate, manganese sulfate, iron chloride (I), iron chloride (III), iron acetate (II), iron nitrate (III), iron sulfate (II), ammonium iron sulfate (III), chloride Cobalt, cobalt nitrate, cobalt acetate, nickel chloride, nickel nitrate, nickel acetate, copper chloride, copper nitrate, zinc chloride, zinc acetate, zinc chloride, yttrium nitrate, yttrium chloride, zirconium chloride, zirconium nitrate, zirconium tetrachloride, Silver chloride, silver acetate, indium chloride, indium acetate, chloride Tin, tin acetate, tin sulfate, cerium chloride, cerium acetate, cerium nitrate, cerium oxalate, diammonium cerium nitrate, cerium sulfate, samarium chloride, samarium nitrate, lead chloride, lead acetate, lead nitrate, lead iodide, phosphoric acid Lead, lead sulfate, lanthanum chloride, lanthanum acetate, lanthanum nitrate, gadolinium nitrate, strontium chloride, strontium acetate, strontium nitrate, niobium pentachloride, ammonium molybdate phosphate, molybdenum sulfide, palladium chloride, palladium acetate, palladium nitrate, pentachloride Antimony, antimony trichloride, antimony trifluoride, telluric acid, barium sulfite, barium chloride, barium chlorate, barium perchlorate, barium acetate, barium nitrate, tungstic acid, ammonium tungstate, tungsten hexachloride, five Tantalum, hafnium chloride, can be exemplified sulfuric hafnium.

  The organometallic compound is not particularly limited as long as it can form a metal oxide film alone, and specific examples thereof include acetylacetonate-based complexes. Examples of the acetylacetonate complex include aluminum acetylacetonate, iron (III) acetylacetonate, nickel (II) acetylacetonate dihydrate, copper (II) acetylacetonate, zinc acetylacetonate, zirconium Tetraacetylacetonate, zirconium monoacetylacetonate, chromium (III) acetylacetonate, cobalt acetylacetonate, tris (acetylacetonato) indium (III), cerium acetylacetonate, lanthanum acetylacetonate, titanium acetylacetonate, Examples thereof include calcium acetylacetonate, molybdenyl acetylacetonate, and palladium acetylacetonate.

  Examples of organometallic compounds other than acetylacetonate complexes include magnesium diethoxide, calcium di (methoxyethoxide), calcium gluconate monohydrate, calcium citrate tetrahydrate, and calcium salicylate dihydrate. , Titanium lactate, tetraisopropyl titanate, tetranormal butyl titanate, tetra (2-ethylhexyl) titanate, butyl titanate dimer, titanium bis (ethylhexoxy) bis (2-ethyl-3-hydroxyhexoxide), diisopropoxy titanium bis (tri Ethanolaminate), dihydroxybis (ammonium lactate) titanium, diisopropoxytitanium bis (ethylacetoacetate), ammonium peroxocitrate tetrahydrate, dicyclopentadi Nyl iron (II), iron (II) lactate trihydrate, copper (II) dipivaloylmethanate, copper (II) ethyl acetoacetate, zinc lactate trihydrate, zinc salicylate trihydrate, stearic acid Zinc, strontium dipivaloylmethanate, yttrium dipivaloylmethanate, zirconium tetra-n-butoxide, zirconium (IV) ethoxide, zirconium normal propylate, zirconium normal butyrate, zirconium acetylacetonate bisethylacetoacetate, Zirconium acetate, zirconium monostearate, penta-n-butoxy niobium, pentaethoxy niobium, pentaisopropoxy niobium, indium (III) 2-ethylhexanoate, tetraethyl tin, dibutyl tin oxide (IV), tricyclohexyl tin (IV) Hydroxide, Li (methoxyethoxy) lanthanum, pentaisopropoxytantalum, pentaethoxytantalum, tantalum (V) ethoxide, lead (II) citrate trihydrate, lead cyclohexanebutyrate, gallium (III) trifluoromethanesulfonate, strontium dipivalo Ilmethanate and the like can be mentioned.

  In the present invention, the metal source is preferably a metal source that provides a metal oxide film with high crystallinity, and among them, a metal source that provides a metal oxide film having a columnar structure is preferable. This is because the effects of the present invention can be sufficiently exhibited. That is, a metal oxide film having sufficiently low crystallinity can be obtained by adding a boron compound to a solution for forming a metal oxide film in which a metal source that gives a metal oxide film having high crystallinity is dissolved. it can. Examples of such metal sources include titanium tetrachloride, chromium chloride, chromium nitrate, chromium sulfate, manganese acetate, manganese nitrate, iron chloride (III), iron nitrate (III), iron sulfate (II), cobalt chloride, nitric acid. Cobalt, cobalt acetate, nickel chloride, nickel nitrate, copper nitrate, zinc chloride, zinc acetate, zinc chloride, chlorinated zirconium oxide, zirconium nitrate oxide, zirconium tetrachloride, diammonium cerium nitrate, iron (III) acetylacetonate, nickel ( II) Acetylacetonate dihydrate, copper (II) acetylacetonate, zinc acetylacetonate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, chromium (III) acetylacetonate, cobalt acetylacetonate, tris ( Acetylacetonato) indium (III), cerium Acetylacetonate, and titanium acetylacetonate.

  The concentration of the metal source in the metal oxide film forming solution is not particularly limited, but for example, within the range of 0.001 to 1 mol / l, particularly within the range of 0.01 to 0.5 mol / l. Preferably there is. This is because if the concentration is within the above range, the metal oxide film can be formed in a relatively short time.

  In the present invention, it is also possible to add a doping metal source for the purpose of doping the metal oxide film. A functional metal oxide film can be obtained by using a doping metal source.

  The kind of the doping metal source is preferably selected as appropriate according to the kind of the target metal oxide film. For example, when obtaining a yttria-stabilized zirconia film (YSZ film) useful as an electrolyte of a solid oxide fuel cell, a metal source having a yttrium element is used as a doping metal source in addition to a metal source having a zirconium element. Specific examples of the metal source having an yttrium element include yttrium nitrate hexahydrate. That is, in the present invention, the metal source is preferably a combination of a zirconium-containing metal source containing a zirconium element and an yttrium-containing metal source containing an yttrium element. This is because a desired YSZ film can be obtained. As described above, the zirconium-containing metal source may be a metal salt containing a zirconium element or an organometallic compound containing a zirconium element, and among them, an organic metal containing a zirconium element. A compound is preferred. Particularly in the present invention, the zirconium-containing metal source is preferably zirconium tetraacetylacetonate. The yttrium-containing metal source is not particularly limited as long as it contains an yttrium element. As described above, it may be a metal salt containing an yttrium element, or an organic metal containing an yttrium element. A compound may be used, but among them, a metal salt containing an yttrium element is preferable. Particularly in the present invention, the yttrium-containing metal source is preferably yttrium nitrate. The ratio of the zirconium-containing metal source and the yttrium-containing metal source contained in the metal oxide film forming solution is not particularly limited as long as a desired YSZ can be obtained. In this case, the yttrium-containing metal source is preferably in the range of 3 to 30, more preferably in the range of 5 to 20, in terms of mole.

  In the present invention, the metal source is preferably a combination of an indium-containing metal source containing an indium element and a tin-containing metal source containing a tin element. This is because an ITO film whose crystal state is changed stepwise or continuously can be obtained. The indium-containing metal source is not particularly limited as long as it contains an indium element. As described above, the indium-containing metal source may be a metal salt containing an indium element, and contains an indium element. An organic metal compound may be used, but among them, a metal salt containing an indium element is preferable. Particularly in the present invention, the indium-containing metal source is preferably indium chloride. On the other hand, the tin-containing metal source is not particularly limited as long as it contains a tin element, and as described above, it may be a metal salt containing a tin element, and contains a tin element. An organic metal compound may be used, but among them, a metal salt containing a tin element is preferable. In particular, in the present invention, the tin-containing metal source is preferably tin chloride.

(2) Boron compound Next, the boron compound used for this invention is demonstrated. The boron compound used in the present invention reduces the crystallinity of the resulting metal oxide film.

  The boron compound is not particularly limited as long as it can reduce the crystallinity of the metal oxide film, but it is preferable that the boron compound has no metal element. This is because the metal element derived from the boron compound can be prevented from being taken into the metal oxide film. Specific examples of the boron compound include boric acid, boron trifluoride-diethyl ether, lithium tetraborate, potassium borohydride, sodium borohydride, lithium tetrafluoroborate, tris (dimethylamino) boron, Examples thereof include triisopropyl borate, sodium peroxoborate tetrahydrate, and tetrafluoroboric acid. Among them, boric acid, boron trifluoride-diethyl ether, tris (dimethyl) are used from the viewpoint of having no metal element. Amino) boron, triisopropyl borate, and tetrafluoroboric acid are preferable, and boric acid is particularly preferable. This is because the crystallinity of the metal oxide film can be reduced more effectively.

It is known that boric acid (H ₃ BO ₃ ) becomes boron oxide (B ₂ O ₃ ) when heated to about 300 ° C. Although the detailed principle is not clear, from some experiments, this boron oxide may be an important factor for reducing the crystallinity of the metal oxide film. From such a viewpoint, the boron compound is preferably a compound that generates boron oxide when it comes into contact with a heated substrate.

  The concentration of the boron compound contained in the metal oxide film forming solution is not particularly limited as long as it is a concentration that can reduce the crystallinity of the metal oxide film. For example, 0.01 mol / l or more In particular, it is preferably in the range of 0.05 to 1 mol / l, particularly preferably in the range of 0.1 to 0.5 mol / l.

(3) Solvent The solvent used in the present invention is not particularly limited as long as it can dissolve the above-described metal source and the like. For example, water; methanol, ethanol, isopropyl alcohol, propanol, butanol Lower alcohols having a total carbon number of 5 or less; toluene; diketones such as acetylacetone, diacetyl, benzoylacetone; ketoesters such as ethyl acetoacetate, ethyl pyruvate, ethyl benzoylacetate, ethyl benzoylformate; and mixed solvents thereof Etc. Depending on the compatibility with the raw material (metal source), for example, the film formation rate may be faster when only methanol is used, or the film formation rate may be higher when acetylacetone is mixed. For this reason, water, methanol, ethanol, acetone, toluene, acetylacetone or a mixed solvent thereof is more preferable. Moreover, it is preferable to use at least one of the above diketones and the above ketoesters as all or part of the solvent. This is because the film forming property is improved.

(4) Additive The metal oxide film forming solution used in the present invention may contain additives such as ceramic fine particles and a surfactant.

  By using the ceramic fine particles, a metal oxide film is formed so as to surround the ceramic fine particles, so that a mixed film of different ceramics can be obtained and the volume of the metal oxide film can be increased. In addition, it is preferable that the content of the ceramic fine particles is appropriately selected according to the characteristics of the member to be used.

  Examples of the ceramic fine particles include ITO, aluminum oxide, zirconium oxide, silicon oxide, titanium oxide, tin oxide, cerium oxide, calcium oxide, manganese oxide, magnesium oxide, and barium titanate. Etc.

  The surfactant acts on the interface between the metal oxide film forming solution and the substrate surface. By using the surfactant, the contact area between the metal oxide film forming solution and the substrate surface can be improved, and a uniform metal oxide film can be obtained. Particularly, when the metal oxide film forming solution is contacted by spraying, the droplets of the metal oxide film forming solution can be sufficiently brought into contact with the substrate surface due to the effect of the surfactant. Used for. In addition, it is preferable to select and use the usage-amount of the said surfactant suitably according to the metal source etc. to be used.

  Examples of the surfactant include Surfinol 485, Surfinol SE, Surfinol SE-F, Surfinol 504, Surfinol GA, Surfinol 104A, Surfinol 104BC, Surfinol 104PPM, Surfinol 104E, Surfinol. Examples include Surfinol series such as Nord 104PA (all manufactured by Nissin Chemical Industry Co., Ltd.), NIKKOL AM301, NIKKOL AM313ON (all manufactured by Nikko Chemical Co., Ltd.), and the like.

2. Next, the substrate used in the present invention will be described. The material of the substrate used in the present invention is not particularly limited as long as it has heat resistance to the above heating temperature. For example, glass, SUS, metal plate, ceramic substrate, heat resistant plastic, etc. Among them, glass, SUS, a metal plate, and a ceramic substrate are preferably used. This is because it is versatile and has sufficient heat resistance.

  The base material used in the present invention is, for example, one having a smooth surface, one having a fine structure, one having a hole, one having a groove, one porous, one porous It may be provided with a film. Of these, those having a smooth surface, those having a fine structure, those having grooves, those which are porous, and those having a porous film are preferably used. Examples of the porous film include those obtained by firing fine metal particles such as titanium oxide.

  In particular, in the present invention, the substrate is preferably a porous substrate or a substrate provided with a porous film. When the surface on which the metal oxide film is formed is porous, the metal oxide crystals are likely to grow from specific points on the porous surface, and grain boundaries are generated at the interface between the substrate and the metal oxide film. However, the electron conductivity and the adhesion are liable to decrease. Even in such a case, in the present invention, by adding a boron compound to the metal oxide film forming solution, the crystallinity of the metal oxide film can be reduced, and the generation of grain boundaries is suppressed. can do.

3. Next, a contact method between the substrate and the metal oxide film forming solution in the present invention will be described. The contact method is not particularly limited as long as it is a method of bringing the above-described metal oxide film forming solution into contact with the above-described base material, but the metal oxide film forming solution and the base material are brought into contact with each other. It is preferable that the method does not lower the temperature of the substrate. This is because if the temperature of the substrate is lowered, the film formation reaction does not occur and a desired metal oxide film may not be obtained. As a method for preventing the temperature of the base material from being lowered, for example, a method of bringing the metal oxide film forming solution into contact with the base material as droplets, and the like are preferable. If the diameter of the droplet is small, the solvent of the metal oxide film forming solution is instantly evaporated, and the decrease in the substrate temperature can be further suppressed. Further, since the droplet diameter is small, a uniform metal This is because an oxide film can be obtained.

  The method for bringing the droplet of the metal oxide film forming solution having such a small diameter into contact with the substrate is not particularly limited. Specifically, the metal oxide film forming solution is sprayed. The method of making it contact with a base material by this, the method of passing a base material in the space which made the metal oxide film formation solution mist-like, etc. are mentioned.

  Examples of the method of bringing the metal oxide film forming solution into contact with the substrate by spraying include a spraying method using a spray device or the like. When spraying using the said spray apparatus etc., it is preferable that the diameter of a droplet is in the range of 0.01-1000 micrometers normally, especially in the range of 0.1-300 micrometers. This is because if the droplet diameter is within the above range, the substrate temperature can be prevented from decreasing, and a uniform metal oxide film can be obtained.

  The spray gas of the spray device is not particularly limited as long as it does not inhibit the formation of the metal oxide film, and examples thereof include air, nitrogen, argon, helium, oxygen and the like. Active gases such as nitrogen, argon and helium are preferred. In addition, the injection amount of the injection gas is, for example, preferably in the range of 0.1 to 50 l / min, and more preferably in the range of 1 to 20 l / min. The spray device may be a fixed device, a movable device, a device that ejects the solution by rotation, a device that ejects only the solution by pressure, or the like. As such a spray device, a commonly used spray device can be used, for example, hand spray (spray gun No. 8012, manufactured by ASONE), ultrasonic nepriser (NE-U17, manufactured by OMRON), etc. Can be used.

  Moreover, in the method of allowing the substrate to pass through the space in which the metal oxide film forming solution is made into a mist, the diameter of the droplets is usually within the range of 0.01 to 300 μm, particularly 0.1 to 100 μm. It is preferable to be within the range. This is because if the droplet diameter is within the above range, the substrate temperature can be prevented from decreasing, and a uniform metal oxide film can be obtained.

  Further, the heating method of the substrate is not particularly limited, and examples thereof include a heating method such as a hot plate, an oven, a firing furnace, an infrared lamp, a hot air blower, etc. A method in which the metal oxide film forming solution can be contacted while maintaining the temperature is preferable, and specifically, a hot plate or the like is preferably used.

  Next, the contact method described above will be specifically described with reference to the drawings. Examples of the method of bringing the metal oxide film forming solution into contact with the substrate by spraying the above-described method include, for example, a method of continuously moving and spraying the substrate with a roller, a method of spraying on a fixed substrate, The method etc. which spray on the flow path like a pipe are mentioned.

  As a method of continuously moving and spraying the base material with the roller, for example, as shown in FIG. 2, using the rollers 4 to 6 that heated the base material 1 to a temperature equal to or higher than the metal oxide film formation temperature. Examples of the method include a method in which the metal oxide film is formed by spraying the solution 2 for forming the metal oxide film with the spray device 3 by continuously moving. This method has an advantage that a metal oxide film can be continuously formed.

  Moreover, as a method of spraying on the fixed base material, for example, as shown in FIG. 1, the base material 1 is heated to a temperature equal to or higher than the metal oxide film formation temperature. A method of forming a metal oxide film by spraying the metal oxide film forming solution 2 using the spray device 3 can be exemplified.

  Moreover, as a method of allowing the substrate to pass through a space in which the above-described metal oxide film forming solution is made into a mist, for example, as shown in FIG. 3, the metal oxide film forming solution 2 is made into a mist. A method of forming a metal oxide film by passing the substrate 1 heated to a temperature equal to or higher than the metal oxide film formation temperature can be given.

4). In addition, in the method for producing a metal oxide film of the present invention, the metal oxide film obtained by the above-described contact method or the like may be washed. The cleaning of the metal oxide film is performed to remove impurities present on the surface of the metal oxide film, for example, a method of cleaning using a solvent used in the metal oxide film forming solution. Etc.

B. Next, the crystallinity reducing material of the present invention will be described. The crystallinity reducing material of the present invention is a crystallinity reducing material that is added to a solution for forming a metal oxide film in which a metal salt or an organometallic compound is dissolved as a metal source, and reduces the crystallinity of the metal oxide film, It consists of a boron compound.

  According to the present invention, the crystallinity of a metal oxide film can be reduced by adding a boron compound to a metal oxide film forming solution containing a metal source.

  The crystallinity reducing material of the present invention is added to a metal oxide film forming solution in which a metal salt or an organometallic compound is dissolved as a metal source. The metal salt, organometallic compound, metal oxide film forming solution, and the like are the same as the contents described in the above “A. Method for producing metal oxide film”, and thus the description thereof is omitted here.

  The crystallinity reducing material of the present invention is made of a boron compound. The boron compound used in the present invention is the same as described in “A. Method for producing metal oxide film” above. Among these, in the present invention, the boron compound is preferably boric acid.

C. Next, the metal oxide film forming solution of the present invention will be described. The metal oxide film forming solution of the present invention is characterized by containing a boron compound that dissolves a metal salt or an organometallic compound as a metal source and lowers the crystallinity of the metal oxide film. .

  According to the present invention, a metal oxide film having low crystallinity can be obtained by using a metal oxide film forming solution to which a boron compound is added.

  The metal oxide film forming solution of the present invention contains at least a metal source and a boron compound. Furthermore, you may contain an oxidizing agent, a reducing agent, an additive, etc. as needed. Since these materials, the concentration of the boron compound, and the like are the same as the contents described in the above-mentioned “A. Method for producing metal oxide film”, description thereof is omitted here.

  The solution for forming a metal oxide film of the present invention is usually used for obtaining a metal oxide film on the substrate by contacting with the substrate heated to a temperature equal to or higher than the metal oxide film forming temperature. It is. The metal oxide film formation temperature, the base material, and the like are the same as those described in the above “A. Method for producing metal oxide film”, and thus the description thereof is omitted here.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be specifically described with reference to examples.

[Example 1-1]
In this example, a ZrO ₂ film was formed on a silicon wafer using a metal oxide film forming solution to which boric acid was added.

  First, a silicon wafer was prepared as a base material. Next, zirconium tetraacetylacetonate (manufactured by Kanto Chemical Co., Inc.) was prepared as a metal source, and a mixed solvent of 20 wt% ethanol and 80 wt% toluene was prepared as a solvent. Thereafter, zirconium tetraacetylacetonate was dissolved in a mixed solvent so as to be 0.1 mol / l and boric acid was 0.1 mol / l to obtain 100 ml of a metal oxide film forming solution. Next, the substrate is heated to 500 ° C. with a hot plate (manufactured by ASONE), and 100 ml of the metal oxide film forming solution is sprayed onto the substrate with an ultrasonic nebulizer (manufactured by OMRON). A metal oxide film was obtained on the substrate.

When the obtained metal oxide film was measured using an X-ray diffractometer (Rigaku, RINT-1500), it was confirmed that there was almost no crystallinity (see FIG. 4). Therefore, when this metal oxide film was measured using a photoelectron spectroscopic analyzer (ESCALAB 200i-XL manufactured by VG Scientific), it was confirmed that a ZrO ₂ film was formed. .

[Example 1-2]
In this example, a ZrO ₂ film was formed on fine particle titanium oxide using a solution for forming a metal oxide film to which boric acid was added. By comparing the result of this example with the result of Comparative Example 1 described later, the effect of reducing the grain boundaries generated at the interface between the base material and the metal oxide film is confirmed.

First, a fine particle titanium oxide layer was produced on a silicon wafer. TiO ₂ fine particles having a primary particle size of 20 nm (P25 manufactured by Nippon Aerosil Co., Ltd.) 37.5 wt%, acetylacetone 1.25 wt%, polyethylene glycol (average molecular weight 3000) 1.88 wt% Then, a slurry was prepared by dissolving and dispersing in isopropyl alcohol. The slurry was applied onto the silicon wafer with a doctor blade, left at room temperature for 20 minutes, and then dried at 100 ° C. for 30 minutes. Thereafter, using an electric muffle furnace (P90 manufactured by Denken), firing was performed at 500 ° C. for 30 minutes in an atmospheric pressure atmosphere. Thereby, the porous film | membrane of the titanium oxide was formed on the silicon wafer, and the base material was obtained.

Next, a metal oxide film was produced in the same manner as in Example 1-1 except that the obtained base material was used. When the substrate and the metal oxide film were observed with a scanning electron microscope, it was confirmed that a ZrO ₂ film having no grain boundary was formed as shown in FIG.

On the other hand, the metal oxide film obtained by the above method was baked using a muffle furnace (P90 manufactured by Denken). The firing condition was that the temperature was raised to 1000 ° C. over 3 hours, kept at 1000 ° C. for 1 hour, and allowed to cool naturally to room temperature. When the base material and metal oxide film after firing were observed using a scanning electron microscope, it was confirmed that a ZrO ₂ film having no grain boundary was formed as shown in FIG. From this, it was confirmed that a dense ZrO ₂ film was maintained even though it was crystallized after the baking treatment.

[Comparative Example 1]
In this comparative example, an experiment was performed in the same manner as in Example 1 except that boric acid was not added.
Zirconium tetraacetylacetonate (manufactured by Kanto Chemical Co., Inc.) was prepared as a metal source, and a mixed solvent of 20 wt% ethanol and 80 wt% toluene was prepared as a solvent. Thereafter, zirconium tetraacetylacetonate was dissolved in the mixed solvent so as to have a concentration of 0.1 mol / l to obtain 100 ml of a metal oxide film forming solution. A metal oxide film was obtained in the same manner as in Example 1 except that this metal oxide film forming solution was used.

When the metal oxide film obtained by the above method was measured using an X-ray diffractometer, it was confirmed that a ZrO ₂ film was obtained. Further, when the substrate and the metal oxide film were observed with a scanning electron microscope, it was confirmed that a ZrO ₂ film having many grain boundaries was formed as shown in FIG.

[Example 2-1]
In this example, an ITO film was prepared using a metal oxide film forming solution to which boric acid was added. By comparing the result of this example with the result of Comparative Example 2 described later, the effect of reducing the grain boundaries generated at the interface between the base material and the metal oxide film is confirmed.

  First, indium chloride (manufactured by Kanto Chemical Co., Inc.) and tin chloride (manufactured by Kanto Chemical Co., Ltd.) were prepared as the metal source, and ethanol (manufactured by Kanto Chemical Co., Ltd.) was prepared as the solvent. Indium chloride was dissolved at 0.1 mol / l, tin chloride at 0.005 mol / l, and boric acid at 0.1 mol / l to obtain 100 ml of a metal oxide film forming solution. Next, the base material is heated to 500 ° C. with a hot plate (manufactured by ASONE), and the solution for forming a metal oxide film is applied to the titanium oxide surface of the base material with an ultrasonic nebulizer (manufactured by OMRON Corporation). Spraying 100 ml, a metal oxide film was obtained on the substrate. Next, the base material used in Example 1 was heated to 500 ° C. with a hot plate (manufactured by ASONE Co., Ltd.), and the solution for forming a metal oxide film was applied to the ultrasonic oxide neprizer (OMRON) on the titanium oxide surface of the base material. 100 ml was sprayed to obtain a metal oxide film on the substrate.

  When the metal oxide film obtained by the said method was measured using the X-ray-diffraction apparatus, it confirmed that the ITO film | membrane was obtained (refer FIG. 7). Moreover, when the base material and the metal oxide film were observed with a scanning electron microscope, it was confirmed that an ITO film without grain boundaries was formed as shown in FIG.

[Example 2-2]
A metal oxide film was produced in the same manner as in Example 2-1, except that boric acid was dissolved in the raw material solution to 0.01 mol / l.
When the metal oxide film obtained by the said method was measured using the X-ray-diffraction apparatus (the Rigaku make, RINT-1500), it confirmed that the ITO film | membrane was obtained (refer FIG. 9). When the base material and the metal oxide film were observed with a scanning electron microscope, it was confirmed that an ITO film without grain boundaries was formed as shown in FIG.

[Comparative Example 2]
In this comparative example, an experiment was performed in the same manner as in Example 2 except that boric acid was not added.
As a metal source, indium chloride was dissolved at 0.1 mol / l and tin chloride at 0.005 mol / l to obtain 100 ml of a metal oxide film forming solution. A metal oxide film was produced in the same manner as in Example 2 except that this metal oxide film forming solution was used.

  When the obtained metal oxide film was measured using an X-ray diffractometer, it was confirmed that an ITO film was obtained (FIG. 11). Moreover, when the base material and the metal oxide film were observed with a scanning electron microscope, it was confirmed that an ITO film with many grain boundaries was formed as shown in FIG.

It is explanatory drawing which shows an example of the manufacturing method of the metal oxide film of this invention. It is explanatory drawing which shows the other example of the manufacturing method of the metal oxide film of this invention. It is explanatory drawing which shows the other example of the manufacturing method of the metal oxide film of this invention. It is a graph which shows the result of the X-ray diffraction measurement of the metal oxide film obtained in Example 1-1. It is a SEM photograph which shows the cross section of the metal oxide film obtained in Example 1-2. 4 is a SEM photograph showing a cross section of the metal oxide film obtained in Comparative Example 1. It is a graph which shows the result of the X-ray-diffraction measurement of the metal oxide film obtained in Example 2-1. It is a SEM photograph which shows the cross section of the metal oxide film obtained in Example 2-1. It is a graph which shows the result of the X-ray diffraction measurement of the metal oxide film obtained in Example 2-2. It is a SEM photograph which shows the cross section of the metal oxide film obtained in Example 2-2. 10 is a graph showing the results of X-ray diffraction measurement of the metal oxide film obtained in Comparative Example 2. 4 is a SEM photograph showing a cross section of the metal oxide film obtained in Comparative Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Metal oxide film formation solution 3 ... Spray apparatus 4, 5, 6 ... Roller

Claims (7)

A metal oxide film forming solution in which a metal salt or an organometallic compound is dissolved as a metal source is brought into contact with a base material heated to a temperature equal to or higher than the metal oxide film forming temperature, whereby a metal oxide film is formed on the base material. A method of manufacturing a metal oxide film to obtain
The method for producing a metal oxide film, wherein the metal oxide film forming solution contains a boron compound that reduces the crystallinity of the metal oxide film.   The method for producing a metal oxide film according to claim 1, wherein the boron compound is boric acid.   The method for producing a metal oxide film according to claim 1 or 2, wherein the substrate is a porous substrate or a substrate provided with a porous film.   The method for producing a metal oxide film according to any one of claims 1 to 3, wherein the metal oxide film forming solution further contains a doping metal source.   Metal elements constituting the metal source are Mg, Al, Si, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Ag, In, Sn, Ce, Sm, Pb, La, The claim according to any one of claims 1 to 4, which is Hf, Sc, Gd, Ca, Cr, Ga, Sr, Nb, Mo, Pd, Sb, Te, Ba, W or Ta. The manufacturing method of the metal oxide film as described in 2. A crystallinity-reducing material that is added to a solution for forming a metal oxide film in which a metal salt or an organometallic compound is dissolved as a metal source, and reduces the crystallinity of the metal oxide film,
A crystallinity-reducing material comprising a boron compound.   A metal oxide film-forming solution comprising a boron compound that dissolves a metal salt or an organometallic compound as a metal source and lowers the crystallinity of the metal oxide film.

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