EP4567161A1

EP4567161A1 - Coated substrate

Info

Publication number: EP4567161A1
Application number: EP23849917.2A
Authority: EP
Inventors: Tomoki MURATA
Original assignee: Niterra Co Ltd
Current assignee: Niterra Co Ltd
Priority date: 2022-08-05
Filing date: 2023-07-20
Publication date: 2025-06-11
Also published as: US20250320623A1; JP7793789B2; KR20250004328A; JPWO2024029362A1; TW202415811A; WO2024029362A1; CN119317738A

Abstract

Provided is a novel coated substrate that is applicable to various fields and can be mass-produced. A coated substrate (1) is obtained by covering a substrate (5) with a film (3). The thickness of the film (3) is 1 nm to 800 nm (exclusive of 800 nm). When the film (3) is measured by X-ray photoelectron spectroscopy, the elemental percentage of C (carbon) is 0.1 atm% to 20 atm% (exclusive of 20 atm%), and the total elemental percentage of metal elements and O (oxygen) is at least 70 atm%. The relative density of the film (3) is at least 90%. The film (3) is amorphous.

Description

TECHNICAL FIELD

The present disclosure relates to a coated substrate.

BACKGROUND ART

Patent Literatures 1 to 4 disclose coated substrates having metal oxide films. In Patent Literatures 1 to 4, a wet film-formation method is employed. Meanwhile, in some cases, a dry film-formation method (dry process) has been employed so as to perform thickness control in accordance with complex substrate shapes.
In consideration of application to various fields and mass production, conventional coated substrates are not necessarily satisfactory, and development of a novel coated substrate has been desired.

CITATION LIST

PATENT LITERATURES

Patent Literature 1: JP2011-32521A
Patent Literature 2: JP2009-147192A
Patent Literature 3: JP2015-93821A
Patent Literature 4: JPH9-202606A

SUMMARY OF INVENTION

TECHNICAL PROBLEM

The present disclosure was made in view of the above-described circumstances, and an object is to provide a novel coated substrate which can be applied to various fields and can be mass produced. The present disclosure can be realized as the following modes.

SOLUTION TO PROBLEM

[1] A coated substrate in which a substrate is coated with a film, wherein
- the thickness of the film is 1 nm or greater and less than 800 nm,
- x-ray photoelectron spectroscopic measurement of the film shows that the percent element composition of C (carbon) is 0.1 atm% or greater and less than 20 atm%, and the total percent element composition of a metal element and O (oxygen) is 70 atm% or greater,
- the relative density of the film is 90% or greater, and
- the film is amorphous.
[2] The coated substrate recited in [1], wherein a portion of the substrate where the film is formed is electrically conductive.
[3] The coated substrate recited in [1] or [2], wherein the film contains a compound having at least one type of structure selected from C-H bond, C=O bond, and C-O bond.
[4] The coated substrate recited in [1] or [2], wherein the x-ray photoelectron spectroscopic measurement of the film shows that the percent element composition of a halogen element is 0.1 atm% or greater.
[5] The coated substrate recited in [1] or [2], wherein the metal element is at least one or more metal elements selected from the group consisting of Al (aluminum), Ti (titanium), Mo (molybdenum), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Zr (zirconium), V (vanadium), W (tungsten), Ta (tantalum), Nb (niobium), and Sn (tin).

ADVANTAGEOUS EFFECT OF INVENTION

According to the present disclosure, there is provided a novel coated substrate which can be applied to various fields and can be mass produced.

BRIEF DESCRIPTION OF DRAWINGS

[FIG. 1] Schematic view of a film formation apparatus.
[FIG. 2] Image of a cross section of a coated substrate in Example 1, the image being obtained by observation under an FIB-SEM.
[FIG. 3] Graph showing the relation between electrodeposition time and deposition weight (deposition mass).
[FIG. 4] Graph showing the relation between the number of samples experimentally produced and the aluminum element concentration of bath liquid.

DESCRIPTION OF EMBODIMENTS

The present disclosure will now be described in detail. Notably, in the present specification, in a description in which "-" is used for a numerical range, the numerical range contains its upper and lower limit values, unless otherwise specifically noted. For example, a description of "10 - 20" should be read to contain both "10" (lower limit value) and "20" (upper limit value). Namely, "10 - 20" has the same meaning as "10 or greater and 20 or less." Also, in the present specification, the upper and lower limit values of various numerical ranges may be combined freely.

1. Coated substrate 1

A coated substrate 1 includes a substrate 5 coated with a film 3. The thickness of the film 3 is 1 nm or greater and less than 800 nm. X-ray photoelectron spectroscopic measurement of the film 3 shows that the percent element composition of C (carbon) is 0.1 atm% or greater and less than 20 atm%, and the total percent element composition of a metal element and O (oxygen) is 70 atm% or greater. The relative density of the film 3 is 90% or greater. The film 3 is amorphous.

(1) Substrate 5

No particular limitation is imposed on the substrate 5. In order to enhance adhesion of the film 3 to the substrate 5, at least a portion (region) of the substrate 5, which portion is to be coated with the film 3, is preferably formed of a material which is electrically conductive and can function as a negative electrode 7 (cathode). In the case where the portion (region) of the substrate 5, which portion is to be coated with the film 3, is electrically conductive and can function as the negative electrode 7 (cathode), the film 3 can be easily formed on that portion by a manufacturing method described below.
A surface portion of the substrate 5 may be formed of a material which is electrically conductive and can function as the negative electrode 7. The entire substrate 5 may be formed of a material which can function as the negative electrode 7. Examples of preferred materials which can serve as the negative electrode 7 include an iron-based alloy and carbon. An example of preferred iron-based alloys is one or more types of alloys selected from Fe-Ni-Cr alloy (stainless steel), Fe-Ni alloy (permalloy), Fe-Si alloy (silicon iron), Fe-Si-Al alloy (Sendust), Fe-Ni-Mo (supermalloy), Fe-Co alloy (permendur), and Fe-C-B alloy (amorphous).

(2) Film 3

(2.1) Thickness

From the viewpoint of enabling the film 3 to exhibit a function corresponding to the material of the film 3, the thickness of the film 3 is 1 nm or greater, preferably 10 nm or greater, more preferably 50 nm or greater. Meanwhile, from the viewpoint of enabling the film 3 to endure stresses generated therein and securing adhesion to the substrate 5, the thickness of the film 3 is less than 800 nm, preferably 500 nm or less, more preferably 200 nm or less. From theses viewpoints, the thickness of the film 3 is 1 nm or greater and less than 800 nm, preferably 10 nm or greater and 500 nm or less, more preferably 50 nm or greater and 200 nm or less. Notably, in the case where the thickness of the film 3 is not uniform, the film 3 satisfies the requirement regarding the thickness when the thickness of at least a portion of the film 3 falls within the above-described range. The thickness of the film 3 can be obtained through observation under an FIB-SEM.

(2.2) Percent element composition of C (carbon)

From the viewpoint of suppressing growth of crystal grains in the film 3 and stabilizing the properties of the film 3, the percent element composition of C (carbon) determined through measurement by x-ray photoelectron spectroscopy (XPS method) is 0.1 atm% or greater, preferably 0.5 atm% or greater, more preferably 1 atm% or greater. Meanwhile, from the viewpoint of enabling the film 3 to sufficiently function as an inorganic film, the percent element composition of C (carbon) is less than 20 atm%, preferably 15 atm% or less, more preferably 10 atm% or less. From these viewpoints, the percent element composition of C (carbon) is 0.1 atm% or greater and less than 20 atm%, preferably 0.5 atm% or greater and 15 atm% or less, more preferably 1 atm% or greater and 10 atm% or less. Notably, in the case where the composition of the film 3 is not uniform, the film 3 satisfies the requirement regarding the percent element composition of C (carbon) when the composition of at least a portion of the film 3 falls within the above-described range.
The composition analysis by the x-ray photoelectron spectroscopy can be performed by using an x-ray photoelectron spectrometer. The measurement can be performed by scanning a cross section under the following measurement conditions: K-alpha rays of aluminum being used as an x-ray source, the beam diameter being set to 100 µm, and the x-ray incident angle in relation to a surface to be analyzed being set to 45°.

(2.3) Total percent element composition of the metal element and O (oxygen)

From the viewpoint of enabling the film 3 to sufficiently function as an inorganic film, the total percent element composition of the metal element and O (oxygen) of the film 3 determined through measurement by the x-ray photoelectron spectroscopy (XPS method) is 70 atm% or greater, preferably 80 atm% or greater, more preferably 90 atm% or greater. Notably, the upper limit of the total percent element composition of the metal element and O (oxygen) is a value obtained by subtracting the percent element composition (atm%) of C (carbon) from 100 atm%. In the case where the composition of the film 3 is not uniform, the film 3 satisfies the requirement regarding the total percent element composition of the metal element and O (oxygen) when the composition of at least a portion of the film 3 falls within the above-described range.

(2.4) Relative density of film 3

From the viewpoint of enabling the film 3 to sufficiently exhibit the function of the film 3, the relative density of the film 3 is 90% or greater, preferably 95% or greater, more preferably 98% or greater. The relative density of the film 3 may be 100%.
The relative density of the film 3 is obtained by the following method. A TEM image of a cross section of the film 3 obtained by cutting the film 3 in the film-thickness direction is obtained. The area of pores in a field of view of 300 nm (vertical dimension) × 1000 nm (horizontal dimension) is measured. The relative density (%) is obtained in accordance with the following expression (1). The average of the relative densities of 10 fields of view is the relative density of the film 3. Notably, in the case where the thickness of the film 3 is smaller than the vertical size of 300 nm, measurement is performed in fields of view determined in accordance with the thickness of the film 3. $Relative density (%) = \{(S 1 - S 2) / S 1\} \times 100$
(In the expression, S1 is the area (nm²) of the field of view of 300 nm (vertical dimension) × 1000 nm (horizontal dimension), and S2 is the total area (nm²) of pores in the field of view of 300 nm (vertical dimension) × 1000 nm (horizontal dimension))

(2.5) Amorphous

The film 3 is amorphous. The fact that the film 3 is amorphous can be confirmed by using a TEM image. Since the film 3 is amorphous, it is expected that crystal grains do not come off and peculiar functions (such as smoothing the outermost surface by uniform film growth) are exhibited.

(2.6) Compound having at least one type of structure selected from C-H bond, C=O bond, and C-O bond

The film 3 preferably contains a compound having at least one type of structure selected from C-H bond, C=O bond, and C-O bond. Since the compound having at least one type of structure selected from C-H bond, C=O bond, and C-O bond vaporizes at a lower temperature as compared with elemental C (carbon) and induces contraction of the film 3, it is supposed that the denseness of the film 3 increases.
Also, since the compound having at least one type of structure selected from C-H bond, C=O bond, and C-O bond remains, it is supposed that the flexibility of the film 3 is maintained, and the adhesion of the film 3 to the substrate 5 is enhanced.

(2.7) Halogen element

The percent element composition of the halogen element as determined through measurement of the film 3 by x-ray photoelectron spectroscopy is preferably 0.1 atm% or greater, more preferably 0.3 atm% or greater, further preferably 0.5 atm% or greater. The upper limit value of the percent element composition of the halogen element is 3 atm% or less.
Since a small amount of halogen element is contained in the film 3, conceivably, the oxide film present on the surface of the substrate 5 is removed by the action of the halogen element, and the film 3 comes into direct contact with the substrate 5. As a result, the adhesion between the substrate 5 and the film 3 is secured.

(2.8) Metal element

No particular limitation is imposed on the metal element. From the viewpoint of causing the film 3 to function as a high quality protection film for the substrate 5, the metal element is preferably at least one or more metal elements selected from the group consisting of Al (aluminum), Ti (titanium), Mo (molybdenum), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Zr (zirconium), V (vanadium), W (tungsten), Ta (tantalum), Nb (niobium), and Sn (tin).

2. Method for manufacturing coated substrate 1

No particular limitation is imposed on a method for manufacturing the coated substrate 1 of the present disclosure.
A preferred manufacturing method will now be described below. The preferred manufacturing method is a method for manufacturing the coated substrate 1 by using a bath liquid 2 containing an organic solvent. The water content of the bath liquid 2 is less than 1 mass% and the bath liquid 2 contains at least one or more types of metal elements and at least one or more types of halogen elements. When a voltage is applied in a state in which the substrate 5 is immersed in the bath liquid 2, the film 3 is formed on the substrate 5, which serves as a negative electrode 7 (cathode). In the manufacturing method of the present disclosure, since electrodeposition is taken place on the negative electrode 7 side, oxidation of the substrate 5 can be suppressed as compared with the case where electrodeposition is taken place on the positive electrode 6 side (anode side).

(1) Bath liquid 2

The bath liquid 2 contains an organic solvent.

(1.1) Water content

From the viewpoint of guaranteeing the homogeneity of the film 3 and suppressing oxidation of the substrate 5, the water content of the bath liquid 2 is rendered less than 1 mass%. The water content is preferably less than 0.5 mass%, more preferably less than 0.1 mass%. The water content may be 0 mass%. The water content of the bath liquid 2 can be obtained by GC-MS analysis.

(1.2) Metal element

The bath liquid 2 contains at least one or more types of metal elements. No particular limitation is imposed on the metal elements. From the viewpoint of causing the film 3 to function as a high quality protection film for the substrate 5, the metal element is preferably at least one or more metal elements selected from the group consisting of Al (aluminum), Ti (titanium), Mo (molybdenum), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Zr (zirconium), V (vanadium), W (tungsten), Ta (tantalum), Nb (niobium), and Sn (tin). In the manufacturing method of the present disclosure, an oxide film depending on the metal element(s) in the bath liquid 2 is formed as the film 3.
The metal element(s) contained in the bath liquid 2 may be supplied as a result of elution of the positive electrode 6 (anode). In the case where the metal element(s) elutes from the positive electrode 6 into the bath liquid 2, control of film formation speed becomes easy, and continuous and stable formation of films on a plurality of substrates 5 becomes possible. In the case where the metal element(s) is supplied to the bath liquid 2 as a result of elution of the positive electrode 6, at least one or more types of electrodes selected from an electrode of Al, an electrode of Ti, and an electrode of Mo are preferably used as the positive electrode 6.
The metal element(s) in the bath liquid 2 may be supplied from a metal alkoxide and/or an inorganic metal compound. In the case where the metal element(s) is supplied as a result of dissolution of a metal alkoxide and/or an inorganic metal compound, it is possible to cope with an element which is difficult to supply by eluting the positive electrode 6 (anode). Also, in this case, it becomes possible to perform film formation in which composition ratios are controlled by combining a plurality of metal elements.
Examples of the metal alkoxide include an aluminum alkoxide, a titanium alkoxide, and a molybdenum alkoxide.
Examples of the aluminum alkoxide include an aluminum trialkoxide. Examples of the aluminum trialkoxide include aluminum tripropoxides (e.g., aluminum triisopropoxide and aluminum tri-n-propoxide), aluminum triethoxide, aluminum tributoxides (e.g., aluminum tri-sec-butoxide and aluminum tri-n-butoxide).
Examples of the titanium alkoxide include a titanium trialkoxide, a titanium tetraalkoxide, and a titanium tetraalkoxide is preferred. Examples of the titanium tetraalkoxide include titanium tetrapropoxides (e.g., titanium tetraisopropoxide and titanium tetra-n-propoxide), titanium tetramethoxide, titanium tetraethoxide, titanium tetrabutoxides (e.g., titanium tetraisobutoxide and titanium tetra-n-butoxide), titanium tetrapentoxides, titanium tetrahexoxides, and titanium tetra (2-ethylhexoxide).
Examples of the inorganic metal compound include aluminum chloride, aluminum bromide, aluminum iodide, and titanium iodide.
In the case where the metal element(s) in the bath liquid 2 is supplied from a metal alkoxide and/or an inorganic metal compound, no particular limitation is imposed on the metal element concentration of the bath liquid 2. In this case, from the viewpoint of forming a satisfactory film 3, the metal element concentration of the bath liquid 2 is preferably 1 ppm or greater and 100 ppm or less, more preferably 3 ppm or greater and 10 ppm or less, further preferably 4 ppm or greater and 6 ppm or less. Notably, "ppm" means "parts per million" and "mg/L." Notably, in the case where the bath liquid 2 contains a plurality of metal elements, the above-described metal element concentration means the total concentration with respect to the plurality of metal elements. The metal element concentration of the bath liquid 2 can be measured by ICP-MS analysis.

(1.3) Halogen element

The bath liquid 2 contains at least one or more types of halogen elements. Since the bath liquid 2 contains a halogen element(s), film formation is performed at a practical speed, and the film 3 is likely to become homogeneous. No particular limitation is imposed on the halogen element. From the viewpoint of enabling prompt progress of organic electrochemical reactions and causing the film 3 to function as a high quality protection film for the substrate 5, the halogen element(s) is preferably at least one or more halogen elements selected from the group consisting of Cl (chlorine), Br (bromine), and I (iodine).
No particular limitation is imposed on the halogen element concentration of the bath liquid 2. From the viewpoint of moderately reducing reaction speed, being advantageous for control of the homogeneity and thickness of the film 3, and preventing separation of the film 3, the halogen element concentration of the bath liquid 2 is preferably 1 ppm or greater and 20000 ppm or less, more preferably 5 ppm or greater and 2000 ppm or less, further preferably 10 ppm or greater and 100 ppm or less. Notably, "ppm" means "parts per million" and "mg/L." The halogen element concentration of the bath liquid 2 can be obtained from the amount of a halogen element(s) added at the time of making-up of the electrolytic bath or by ICP-MS analysis.

(1.4) Organic solvent

Since an organic solvent is used as the solvent of the bath liquid 2, generation of gas and oxidation of the substrate 5 itself during film formation are suppressed. From the viewpoint of satisfactory formation of the film 3, the solvent preferably contains at least one or more types of solvents selected from the group consisting of ketones and nitriles. In the case where the solvent contains a ketone and/or a nitrile, it is supposed that a condensation reaction occurs on the electrode surface (cathode surface) and electrodeposition becomes possible. Also, in the case where the solvent contains a ketone, conceivably, ketoenol tautomerism occurs in the presence of halogen, and the reactivity of the bath liquid 2 is enhanced.

(1.4.1) Ketone

No particular limitation is imposed on the ketone so long as the ketone is an organic solvent having a carbonyl group (-C(=O)-) other than ester bond.
Examples of the ketone include acetone, methyl ethyl ketone (MEK), 1-hexanone, 2-hexanone, 4-heptanone, 2-heptanone (methyl amyl ketone), 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, diisobutyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, phenylacetone, acetophenone, methyl naphthyl ketone, cyclohexanone (CHN), and methylcyclohexanone. Among these, acetone and methyl ethyl ketone are preferred, because the film 3 is formed particularly satisfactorily.

(1.4.2) Nitrile

Nitrile is an organic solvent which contains a nitrile group (-CN) in its structure. Examples of the nitrile include acetonitrile, propionitrile, valeronitrile, and butyronitrile. Among these, acetonitrile is preferred, because the film 3 is formed particularly satisfactorily.

(2) Substrate 5

As to the "substrate 5," the description in the column entitled "(1) Substrate 5" in the above-described section entitled "1. Coated substrate 1" is applied as it is.

(3) Voltage application

By applying a voltage to the substrate 5 immersed in the bath liquid 2, a film 3 is formed on the substrate 5, which serves as the negative electrode 7. Specifically, the positive electrode 6 and the negative electrode 7 (the substrate 5) are immersed into the bath liquid 2, and a potential gradient is generated between the two electrodes.
Any of known electrically conductive substrates may be used as the positive electrode 6. In the case where the metal element(s) in the bath liquid 2 is supplied as a result of elution of the positive electrode 6, at least one or more types of electrodes selected from an electrode of Al, an electrode of Ti, and an electrode of Mo are preferably used as the positive electrode 6. No particular limitation is imposed on the shape, thickness, size, etc. of the positive electrode 6. The positive electrode 6 may be foil like, plate like, foam like, nonwoven fabric like, mesh like, felt like, or expanded metal like.
The positive electrode 6 and the negative electrode 7 are preferably disposed to face each other.
The positive electrode 6 and the negative electrode 7 are connected to a DC power supply, which can generate a potential gradient between the positive electrode 6 and the negative electrode 7.
For generation of a potential gradient between the positive electrode 6 and the negative electrode 7, in a state in which the positive electrode 6 and the negative electrode 7 are immersed in the bath liquid 2, a voltage (for example, constant voltage) is applied to the positive electrode 6 and the negative electrode 7 by the power supply connected to the positive electrode 6 and the negative electrode 7.
From the viewpoint of performing film formation at a practical speed, in the case where a constant voltage is applied, the potential gradient generated between the two electrodes is preferably 10 V or higher and 300 V or lower, more preferably 20 V or higher and 100 V or lower, further preferably 60 V or higher and 80 V or lower.
No particular limitation is imposed on an application time during which the volage is applied. The application time is, for example, preferably 10 seconds or longer and 300 seconds or shorter, more preferably 30 seconds or longer and 240 seconds or shorter, further preferably 60 seconds or longer and 180 seconds or shorter.
Notably, the voltage is not required to be a constant voltage and the magnitude of the voltage may be changed.

(4) Treatment process after film formation

After formation of the film 3, the amount of carbon in the film 3 may be reduced by means of heat treatment and/or light irradiation. By reducing the amount of carbon in the film 3 by means of heat treatment and/or light irradiation, it is possible to control the purity of the film 3 as an inorganic oxide film.
No particular limitation is imposed on the treatment temperature of the heat treatment. From the viewpoint of efficiently reducing the amount of carbon, the treatment temperature is preferably 100°C or higher and 1000°C or lower, more preferably 300°C or higher and 800°C or lower, further preferably 500°C or higher and 600°C or lower.
No particular limitation is imposed on the treatment time of the heat treatment. From the viewpoint of efficiently reducing the amount of carbon, the treatment time is preferably 1 minute or longer and 60 minutes or shorter, more preferably 5 minutes or longer and 45 minutes or shorter, further preferably 10 minutes or longer and 30 minutes or shorter.
No particular limitation is imposed on the wavelength of light used for light irradiation. From the viewpoint of efficiently reducing the amount of carbon, the wavelength of light is preferably 250 nm or longer and 1100 nm or shorter, more preferably 300 nm or longer and 800 nm or shorter, further preferably 400 nm or longer and 500 nm or shorter.
No particular limitation is imposed on the light irradiation time. From the viewpoint of efficiently reducing the amount of carbon, the light irradiation time is preferably 3 seconds or longer and 120 seconds or shorter, more preferably 5 seconds or longer and 60 seconds or shorter, further preferably 10 seconds or longer and 30 seconds or shorter.
Notably, reduction of the amount of carbon in the film 3 can be confirmed by XPS analysis.

3. Action and effects of coated substrate 1 of present embodiment

According to the present embodiment, there is provided the novel coated substrate 1 which can be applied to various fields and can be mass produced.
The coated substrate 1 of the present embodiment can be formed without use of an expensive material or by using only a small amount of an expensive material. Therefore, the coated substrate 1 is advantageous in terms of cost.
Also, in the coated substrate 1 of the present embodiment, since post treatments, such as heat treatment and light irradiation, are not necessarily needed for formation of the film 3, it is possible to expand the choices of the material and shape of the substrate 5.

EXAMPLES

The present disclosure will be described further specifically by means of example.
Notably, in the following description, measurement conditions of XPS (x-ray photoelectron spectroscopy) are as follows.

[Measurement conditions]

X-ray beam diameter: 100 µmΦ
Signal reception angle: 45.0°
Path energy: 140 eV
Ar etching for 30 seconds (etching rate: 10 nm/min corresponding to SiO₂)

1. Examples in which a metal element(s) is supplied into the bath liquid 2 as a result of elution of the positive electrode 6

(1) Example 1 (solvent: MEK, positive electrode 6: aluminum)

The film formation apparatus 11 shown in FIG. 1 was used. An aluminum wire was used as the positive electrode 6. A stainless plate was used as the negative electrode 7. The negative electrode 7 is a substrate 5 on which a film 3 is to be formed. Methyl ethyl ketone (MEK) was used as the solvent of the bath liquid 2. Iodine (halogen) was dissolved in the bath liquid 2 at a concentration of 600 ppm.
In a state in which the positive electrode 6 and the negative electrode 7 were immersed in the bath liquid 2, a voltage of 80 V was applied between the positive electrode 6 and the negative electrode 7 for three minutes.
Observation of a cross section of the negative electrode 7 under an FIB-SEM (focused ion beam scanning electron microscope) revealed that, as shown in FIG. 2, a film 3 of 700 nm was formed on the surface of the substrate 5. Analysis performed after Ar etching by XPS for 30 seconds revealed that the film 3 is aluminum oxide.
The percent element composition of carbon in the film 3 was 5.8 atm%, and the total percent element composition of aluminum and oxygen was 93.9 atm%.
The percent element composition of iodine in this film 3 was less than 0.1 atm% (lower measurement limit).
Since no crystal grain was observed in a TEM image of a cross section of the film 3 obtained by cutting the film 3 in the film-thickness direction, it was confirmed that the film 3 is amorphous.
The relative density of the film 3 determined by the following method was 100%.
Specifically, the relative density of the film 3 was determined as follows. A TEM image was obtained from a cross section of the film 3 obtained by cutting the film 3 in the film-thickness direction. The area of pores was measured in a field of view of 300 nm (vertical dimension) × 1000 nm (horizontal dimension). The relative density (%) was obtained in accordance with the following expression (1). The average of the relative densities of 10 fields of view is the relative density of the film 3. Notably, in the case where the thickness of the film 3 is smaller than the vertical size of 300 nm, measurement is performed in fields of view determined in accordance with the thickness of the film 3. $Relative density (%) = \{(S 1 - S 2) / S 1\} \times 100$
(In the expression, S1 is the area (nm²) of the field of view of 300 nm (vertical dimension) × 1000 nm (horizontal dimension), and S2 is the total area (nm²) of pores in the field of view of 300 nm (vertical dimension) × 1000 nm (horizontal dimension))

(2) Example 2 (solvent: acetone, positive electrode 6: aluminum)

Acetone was used as the solvent of the bath liquid 2. Iodine (halogen) was dissolved in the bath liquid 2 at a concentration of 14 ppm. An experiment was carried out under the same conditions as Example 1, except for the above described points. Observation of a cross section of the negative electrode 7 under the FIB-SEM revealed that a film 3 of 130 nm was formed on the surface of the substrate 5. Analysis by means of XPS revealed that the film 3 is aluminum oxide.
The percent element composition of carbon in the film 3 was 6.5 atm%, and the total percent element composition of aluminum and oxygen was 93.3 atm%.
The percent element composition of iodine in this film 3 was 0.1 atm%.
Since no crystal grain was observed in a TEM image of a cross section of the film 3 obtained by cutting the film 3 in the film-thickness direction, it was confirmed that the film 3 is amorphous.
The relative density of the film 3 determined by the above-described method was 100%.

(3) Example 3 (solvent: MEK, positive electrode 6: titanium)

A titanium wire was used as the positive electrode 6. An experiment was carried out under the same conditions as Example 1, except for the above described point. Observation of a cross section of the negative electrode 7 under the FIB-SEM revealed that a film 3 of 90 nm was formed on the surface of the substrate 5. Analysis by means of XPS revealed that the film 3 is titanium oxide.
The percent element composition of carbon in the film 3 was 24.6 atm%, and the total percent element composition of titanium and oxygen was 78.7 atm%.
The percent element composition of iodine in this film 3 was 0.3 atm%.
Since no crystal grain was observed in a TEM image of a cross section of the film 3 obtained by cutting the film 3 in the film-thickness direction, it was confirmed that the film 3 is amorphous.
The relative density of the film 3 determined by the above-described method was 100%.

(4) Example 4 (solvent: acetone, positive electrode 6: titanium)

Acetone was used as the solvent of the bath liquid 2. Iodine (halogen) was dissolved in the bath liquid 2 at a concentration of 2400 ppm. An experiment was carried out under the same conditions as Example 3, except for the above described points. Observation of a cross section of the negative electrode 7 under the FIB-SEM revealed that a film 3 of 500 nm was formed on the surface of the substrate 5. Analysis by means of XPS revealed that the film 3 is titanium oxide.
The percent element composition of carbon in the film 3 was 9.2 atm%, and the total percent element composition of titanium and oxygen was 83.7 atm%.
The percent element composition of iodine in this film 3 was 0.4 atm%.
Since no crystal grain was observed in a TEM image of a cross section of the film 3 obtained by cutting the film 3 in the film-thickness direction, it was confirmed that the film 3 is amorphous.
The relative density of the film 3 determined by the above-described method was 100%.

(5) Example 5 (solvent: MEK, positive electrode 6: molybdenum)

A molybdenum wire was used as the positive electrode 6. An experiment was carried out under the same conditions as Example 1, except for the above described point. Observation of a cross section of the negative electrode 7 under the FIB-SEM revealed that a film 3 of 160 nm was formed on the surface of the substrate 5. Analysis by means of XPS revealed that the film 3 is molybdenum oxide.
The percent element composition of carbon in the film 3 was 14.8 atm%, and the total percent element composition of molybdenum and oxygen was 78.7 atm%.
The percent element composition of iodine in this film 3 was less than 0.1 atm% (detection limit or lower).
Since no crystal grain was observed in a TEM image of a cross section of the film 3 obtained by cutting the film 3 in the film-thickness direction, it was confirmed that the film 3 is amorphous.
The relative density of the film 3 determined by the above-described method was 100%.

(6) Example 6 (solvent: acetone, positive electrode 6: molybdenum)

Acetone was used as the solvent of the bath liquid 2. Iodine (halogen) was dissolved in the bath liquid 2 at a concentration of 2400 ppm. An experiment was carried out under the same conditions as Example 5, except for the above described points. Observation of a cross section of the negative electrode 7 under the FIB-SEM revealed that a film 3 of 480 nm was formed on the surface of the substrate 5. Analysis by means of XPS revealed that the film 3 is molybdenum oxide.
The percent element composition of carbon in the film 3 was 12.7 atm%, and the total percent element composition of molybdenum and oxygen was 78.0 atm%.
The percent element composition of iodine in this film 3 was less than 0.1 atm% (detection limit or lower).
Since no crystal grain was observed in a TEM image of a cross section of the film 3 obtained by cutting the film 3 in the film-thickness direction, it was confirmed that the film 3 is amorphous.
The relative density of the film 3 determined by the above-described method was 100%.

(7) Example 7 (solvent: acetonitrile, positive electrode 6: aluminum)

Acetonitrile was used as the solvent of the bath liquid 2. Iodine (halogen) was dissolved in the bath liquid 2 at a concentration of 2400 ppm. An experiment was carried out under the same conditions as Example 1, except for the above described points. Observation of a cross section of the negative electrode 7 under the FIB-SEM revealed that a film 3 of 140 nm was formed on the surface of the substrate 5. Analysis by means of XPS revealed that the film 3 is aluminum oxide. Oxygen which was not present in the bath liquid 2 was present in the film 3. It is supposed that oxygen was originated from water contained in the bath liquid 2 or moisture absorbed from the atmosphere.
The percent element composition of carbon in the film 3 was 9.8 atm%, and the total percent element composition of aluminum and oxygen was 90.1 atm%.
The percent element composition of iodine in this film 3 was 0.1 atm%.
Since no crystal grain was observed in a TEM image of a cross section of the film 3 obtained by cutting the film 3 in the film-thickness direction, it was confirmed that the film 3 is amorphous.
The relative density of the film 3 determined by the above-described method was 100%.

2. Examples in which a metal element(s) is supplied into the bath liquid from metal alkoxide

(1) Example 8 (solvent: acetone, metal alkoxide: aluminum triisopropoxide)

The film formation apparatus 11 shown in FIG. 1 was used. A carbon electrode was used as the positive electrode 6. A stainless plate was used as the negative electrode 7. The negative electrode 7 is a substrate 5 on which a film 3 is to be formed. Acetone was used as the solvent of the bath liquid 2.
Aluminum triisopropoxide was dissolved in the bath liquid 2 at a concentration of 16 mg/L (16 ppm), and iodine (halogen) was dissolved in the bath liquid 2 at a concentration of 2400 mg/L (2400 ppm).
In a state in which the positive electrode 6 and the negative electrode 7 were immersed in the bath liquid 2, a voltage of 80 V was applied between the positive electrode 6 and the negative electrode 7 for three minutes.
Observation of a cross section of the negative electrode 7 under an FIB-SEM (focused ion beam scanning electron microscope) revealed that a film 3 of 140 nm was formed on the surface of the substrate 5. Analysis by means of XPS (x-ray photoelectron spectroscopy) revealed that the film 3 is aluminum oxide.
The percent element composition of carbon in the film 3 was 8.4 atm%, and the total percent element composition of aluminum and oxygen was 84.3 atm%.
The percent element composition of iodine in this film 3 was less than 0.1 atm% (detection limit or lower).
Since no crystal grain was observed in a TEM image of a cross section of the film 3 obtained by cutting the film 3 in the film-thickness direction, it was confirmed that the film 3 is amorphous.
The relative density of the film 3 determined by the above-described method was 100%.

(2) Example 9 (solvent: MEK, metal alkoxide: aluminum triisopropoxide)

Methyl ethyl ketone (MEK) was used as the solvent of the bath liquid 2. An experiment was carried out under the same conditions as Example 8, except for the above described point.
Observation of a cross section of the negative electrode 7 under the FIB-SEM revealed that a film 3 of 300 nm was formed on the surface of the substrate 5. Analysis by means of XPS revealed that the film 3 is aluminum oxide.
The percent element composition of carbon in the film 3 was 8.6 atm%, and the total percent element composition of aluminum and oxygen was 83.6 atm%.
The percent element composition of iodine in this film 3 was less than 0.1 atm% (detection limit or lower).
Since no crystal grain was observed in a TEM image of a cross section of the film 3 obtained by cutting the film 3 in the film-thickness direction, it was confirmed that the film 3 is amorphous.
The relative density of the film 3 determined by the above-described method was 100%.

(3) Example 10 (solvent : acetone, metal alkoxide: titanium tetraisopropoxide)

In place of aluminum triisopropoxide, titanium tetraisopropoxide was used. An experiment was carried out under the same conditions as Example 8, except for the above described point. Observation of a cross section of the negative electrode 7 under the FIB-SEM revealed that a film 3 of 700 nm was formed on the surface of the substrate 5.
Analysis by means of XPS revealed that the film 3 is titanium oxide.
The percent element composition of carbon in the film 3 was 8.8 atm%, and the total percent element composition of titanium and oxygen was 86.1 atm%.
The percent element composition of iodine in this film 3 was 1.3 atm%.
Since no crystal grain was observed in a TEM image of a cross section of the film 3 obtained by cutting the film 3 in the film-thickness direction, it was confirmed that the film 3 is amorphous.
The relative density of the film 3 determined by the above-described method was 100%.

(4) Example 11 (solvent : acetone, metal alkoxide: titanium tetra-n-propoxide)

In place of aluminum triisopropoxide, titanium tetra-n-propoxide was used. An experiment was carried out under the same conditions as Example 8, except for the above described point. Observation of a cross section of the negative electrode 7 under the FIB-SEM revealed that a film 3 of 510 nm was formed on the surface of the substrate 5. Analysis by means of XPS revealed that the film 3 is titanium oxide.
The percent element composition of carbon in the film 3 was 9.5 atm%, and the total percent element composition of titanium and oxygen was 85.9 atm%.
The percent element composition of iodine in this film 3 was 0.9 atm%.
Since no crystal grain was observed in a TEM image of a cross section of the film 3 obtained by cutting the film 3 in the film-thickness direction, it was confirmed that the film 3 is amorphous.
The relative density of the film 3 determined by the above-described method was 100%.

3. Analysis of film 3 by FT-IR

The films 3 formed in Examples 1, 2, 3, and 7 were analyzed by FT-IR. The measurement conditions are as follows.

Measurement method: One-time reflection ATR method
Scanning times: 64 times
Resolution: 4 cm^-1
Aperture: 150 µm

In each of the films 3, a peak which is conceivably attributed to C-H stretching was detected in the range of 3000 cm^-1 to 2800 cm^-1.

4. Analysis of films 3 by XPS

The films 3 formed in Examples 1, 2, and 3 were analyzed by XPS. In each of the films 3, C=O bond and C-O bond were detected.

5. Difference in film formation speed among different types of solvents

The relation between electrodeposition time and deposition weight was investigated for different types of solvents.
The film formation apparatus 11 shown in FIG. 1 was used. An aluminum wire was used as the positive electrode 6. A stainless plate was used as the negative electrode 7. The negative electrode 7 serves as a substrate 5 on which a film 3 is to be formed. Various types of solvents such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, and diisobutyl ketone were used as solvents of bath liquids 2. Iodine (halogen) was dissolved in each bath liquid 2 at a concentration of 2100 mg/L (2100 ppm).
In a state in which the positive electrode 6 and the negative electrode 7 were immersed in the bath liquid 2, a voltage of 80 V was applied between the positive electrode 6 and the negative electrode 7 for one to three minutes.
The graph of FIG. 3 shows the relation between application time (electrodeposition time) and deposition weight (deposition mass) for cases where the respective solvents were used. The deposition weight is the weight of the formed film.
It was confirmed from the graph of FIG. 3 that, as the electrodeposition time increases, the deposition weight increases. Also, it was confirmed from the graph of FIG. 3 that the smaller the number of carbon atoms of a hydrocarbon group of the solvent, the higher the deposition speed.

6. Relation between metal element concentration of bath liquid 2 and adhesiveness of film 3

A first sample (coated substrate 1) was produced in the same manner as in Example 1. After having pulled out the first sample from the bath liquid 2, a new stainless plate was immersed into the bath liquid 2, and a voltage was applied in the same manner as in Example 1, thereby producing a second sample. In the same manner, third and fourth samples were produced. When each sample was pulled out from the bath liquid 2, a portion of the bath liquid 2 was sampled, and the aluminum element concentration was measured by ICP-MS.
The graph of FIG. 4 shows the relation between the number of samples experimentally produced and the aluminum element concentration of the bath liquid 2. It was found from the graph of FIG. 4 that the aluminum element concentration tends to increase with the number of samples experimentally produced. In the fourth sample, the film 3 tended to separate from the substrate 5. Therefore, it was found that, for continuous production of samples, the aluminum element concentration is preferably 1 ppm or greater and 6 ppm or less.

7. Relation between halogen element concentration of the bath liquid 2 and adhesiveness of film

The film formation apparatus 11 shown in FIG. 1 was used. An aluminum wire was used as the positive electrode 6. A stainless plate was used as the negative electrode 7. The negative electrode 7 serves as a substrate 5 on which a film 3 is to be formed. Various types of solvents (i.e., acetone and methyl ethyl ketone (MEK)) were used as solvents of bath liquids 2. Iodine (halogen) was dissolved in the bath liquids 2 in amounts shown Table 1.
In a state in which the positive electrode 6 and the negative electrode 7 were immersed in the bath liquid 2, a voltage of 80 V was applied between the positive electrode 6 and the negative electrode 7 for three minutes, thereby producing a first sample (coated substrate 1). After having pulled out the first sample from the bath liquid 2, a new stainless plate was immersed into the bath liquid 2, and a voltage was applied in the same manner as in the case of the first sample, thereby producing a second sample. In the same manner, a third sample and subsequent samples were continuously produced.
The results are shown in Table 1. The evaluations in Table 1 are as follows.

A: The film 3 was formed. Adhesion between the film 3 and the substrate 5 was satisfactory.
B: The film 3 was formed. Adhesion between the film 3 and the substrate 5 was somewhat poor, and the film 3 tended to separate.

The results of Table 1 demonstrate that formation of the film 3 was possible irrespective of the iodine concentration. It was confirmed that, from the viewpoint of preventing separation of the film 3, the iodine concentration is preferably 0.001 g/L or greater and 0.10 g/L or less (1 mg/L or greater and 100 mg/L or less = 1 ppm or greater and 100 ppm or less).

Table 1

Solvent	Amount of iodine (g/L)	Film formation state
Solvent	Amount of iodine (g/L)	First sample	Second sample	Third sample	Fourth sample	Fiftieth sample
Acetone	0.014	A	A	A	A	A
	0.14	A	A	B	B	-
	0.6	A	B	B	B	-
	1.2	A	A	B	B	-
	2.4	A	A	A	B	-
MEK	0.014	A	A	A	A	A
	0.6	A	A	A	B	-
	1.2	A	A	A	B	-
	2.4	A	B	B	B	-

8. Study on type of substrate 5

Formation of the film 3 was attempted for cases where various types of substrates 5 were use. Instead of the stainless plate used as the negative electrode 7 in Example 1, a permalloy plate, a titanium plate, a copper plate, and a carbon plate were used, respectively. Experiments were carried out under the same conditions as in Example 1 except for the above-described point.
The film 3 was stably formed on each of the substrates 5. Therefore, it was confirmed that stable formation of the film 3 is possible irrespective of the type of the substrate 5.

9. Effects of Examples

According to the present examples, novel coated substrates 1 which can be applied to various fields and can be mass-produced are provided.
The present invention is not limited to the embodiment described in detail above and various modifications and changes are possible within the range shown in the claims of the present invention.

(Additional note)

The following inventions are contained in the present specification.

[1] A coated substrate in which a substrate is coated with a film, wherein
- the thickness of the film is 1 nm or greater and less than 800 nm,
- x-ray photoelectron spectroscopic measurement of the film shows that the percent element composition of C (carbon) is 0.1 atm% or greater and less than 20 atm%, and the total percent element composition of a metal element and O (oxygen) is 70 atm% or greater,
- the relative density of the film is 90% or greater, and
- the film is amorphous.
[2] The coated substrate recited in [1], wherein a portion of the substrate where the film is formed is electrically conductive.
[3] The coated substrate recited in [1] or [2], wherein the film contains a compound having at least one type of structure selected from C-H bond, C=O bond, and C-O bond.
[4] The coated substrate recited in any one of [1] to [3], wherein the x-ray photoelectron spectroscopic measurement of the film shows that the percent element composition of a halogen element is 0.1 atm% or greater.
[5] The coated substrate recited in any one of [1] to [4], wherein the metal element is at least one or more metal elements selected from the group consisting of Al (aluminum), Ti (titanium), Mo (molybdenum), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Zr (zirconium), V (vanadium), W (tungsten), Ta (tantalum), Nb (niobium), and Sn (tin).

REFERENCE SIGNS LIST

1: coated substrate
2: bath liquid
3: film
5: sub strate
6: positive electrode
7: negative electrode
11: film formation apparatus

Claims

A coated substrate in which a substrate is coated with a film, wherein
the thickness of the film is 1 nm or greater and less than 800 nm,

x-ray photoelectron spectroscopic measurement of the film shows that the percent element composition of C (carbon) is 0.1 atm% or greater and less than 20 atm%, and the total percent element composition of a metal element and O (oxygen) is 70 atm% or greater,

the relative density of the film is 90% or greater, and

the film is amorphous.
A coated substrate according to claim 1, wherein a portion of the substrate where the film is formed is electrically conductive.
A coated substrate according to claim 1 or 2, wherein the film contains a compound having at least one type of structure selected from C-H bond, C=O bond, and C-O bond.
A coated substrate according to claim 1 or 2, wherein the x-ray photoelectron spectroscopic measurement of the film shows that the percent element composition of a halogen element is 0.1 atm% or greater.
A coated substrate according to claim 1 or 2, wherein the metal element is at least one or more metal elements selected from the group consisting of Al (aluminum), Ti (titanium), Mo (molybdenum), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Zr (zirconium), V (vanadium), W (tungsten), Ta (tantalum), Nb (niobium), and Sn (tin).