WO2022114027A1 - Film-attached glass substrate, and method for manufacturing same - Google Patents

Abstract

The present invention relates to a film-attached glass substrate comprising a glass substrate, an undercoat layer, and a functional transparent film in this order, wherein the undercoat layer is a SiO_xC_y layer, wherein in SiO_xC_y constituting the SiO_xC_y layer, a value of x is 1.59-1.90, and a value of y is 0.10-0.40.

Description

Glass substrate with film and its manufacturing method

The present invention relates to a glass substrate with a film and a method for manufacturing the same, and particularly to a transparent electrode substrate used for a solar cell or a glass substrate with a film to be Low-E glass.

Since the glass substrate with a film has properties such as transparency, chemical stability, high hardness, heat resistance, insulation, and excellent optical properties, it is not only a window glass material that is a building member, but also an optical component. It is used in various fields such as electrical parts and electronic parts.

For example, in a solar cell, a glass substrate with a film is used as a transparent electrode substrate having a transparent conductive film formed on the surface of the glass substrate. Further, in the field of construction, low emissivity glass (Low-E glass) having heat insulating properties and heat shielding properties by forming an oxide film or a metal film on the surface of a glass substrate is used.

In a glass substrate with a film having a transparent conductive film or a metal oxide film (hereinafter referred to as a functional transparent film), alkali metal ions diffuse from the glass substrate to the functional transparent film to form a functional transparent film. Performance may deteriorate. In order to suppress this, it is considered to provide an undercoat layer between the functional transparent film and the glass substrate.

As the undercoat layer, for example, SiO ₂ or the like is known to be used (for example, Patent Document 1). However, when SiO ₂ is used as the undercoat layer, the reflection of light in the glass substrate with a film due to the difference in refractive index between the undercoat layer and the functional transparent film cannot be sufficiently suppressed, and the light transmittance of the glass substrate with a film cannot be sufficiently suppressed. Cannot be sufficiently improved.

Therefore, it has been studied to use SiO _{x Cy} as an undercoat layer having a relatively small difference in refractive index from a functional transparent film or a glass plate. For example, Patent Document 2 discloses a glass plate with a transparent conductive film including a base film containing silicon, oxygen, and carbon.

Japanese Patent Application Laid-Open No. 6-191894 Japanese Patent Application Laid-Open No. 2005-029463

When manufacturing a specific solar cell such as a CdTe solar cell or heat-strengthening Low-E glass, the glass substrate with a film may be placed in a high temperature environment of 600 ° C. or higher.

However, when SiO _{x Cy} disclosed in Patent Document 2 or the like is used for the undercoat layer, the carbon of SiO _{x Cy} tends to diffuse into the functional transparent film, especially in a high temperature environment of 600 ° C. or higher. I've come to understand. When carbon is diffused into the functional transparent film, the conductive substance and the low radioactive substance in the functional transparent film are reduced by the carbon, and the performance such as conductivity and thermal radiation of the functional transparent film is deteriorated.

Under these circumstances, there is a demand for a glass substrate with a film having excellent light transmittance and also excellent heat resistance in a high temperature environment.
Therefore, an object of the present invention is to provide a glass substrate with a film, which can be used as a transparent electrode substrate for a solar cell or Low-E glass, has excellent heat resistance, and is also excellent in light transmission.

As a result of studying the above problems, the present inventors have found that excellent heat resistance and light transmittance can be achieved at the same time by adjusting the composition of SiO _{x Cy} constituting the undercoat layer to a specific range. rice field.

That is, the present invention relates to the following [1] to [9].
[1] A glass substrate with a film containing a glass substrate, an undercoat layer, and a functional transparent film in this order.
The undercoat layer is a SiO _{x Cy} layer, and the undercoat layer is a SiO x Cy layer.
A glass substrate with a film having a value of x of 1.59 to 1.90 and a value of _y of 0.10 to 0.40 in SiO _{x Cy constituting the SiO x Cy layer} .
[2] The glass substrate with a film according to the above [1], wherein the undercoat layer has a thickness of 10 to 90 nm.
[3] The glass substrate with a film according to the above [1] or [2], wherein the main component of the functional transparent film is SnO ₂ .
[4] The glass substrate with a film according to any one of [1] to [3], wherein the functional transparent film includes a conductive layer and a surface layer in this order from the glass substrate side.
[5] A solar cell having the glass substrate with a film according to any one of [1] to [4] as a transparent electrode substrate.
[6] Low-E glass comprising the glass substrate with a film according to any one of [1] to [3] above.
[7] A method for manufacturing a glass substrate with a film.
By reacting a glass substrate heated to a temperature of 500 to 800 ° C. with a gas raw material to form an undercoat layer on the glass substrate,
Including forming a functional transparent film on the undercoat layer.
The undercoat layer is a SiO _{x Cy} layer, and is
The gaseous raw material contains a silicon-containing substance, an oxidizing agent and an unsaturated hydrocarbon, and contains
The volume ratio of the oxidizing agent to the silicon-containing substance is 8.5 to 50, and the volume ratio is 8.5 to 50.
The volume ratio of the unsaturated hydrocarbon to the silicon-containing substance is 0.5 to 3.5.
A method for manufacturing a glass substrate with a film.
[8] The method for producing a glass substrate with a film according to the above [7], wherein the silicon-containing substance contains silane, the oxidizing agent contains carbon dioxide, and the unsaturated hydrocarbon contains ethylene.
[9] The method for producing a glass substrate with a film according to the above [7] or [8], wherein the undercoat layer has a thickness of 10 to 90 nm.

According to the glass substrate with a film according to the present invention, the composition of the undercoat layer is adjusted to a specific range, so that it has excellent heat resistance when used as a transparent electrode substrate for a solar cell or Low-E glass. It also has excellent light transmission.

FIG. 1 is a schematic cross-sectional view illustrating the configuration of a glass substrate with a film. FIG. 2 is a schematic cross-sectional view illustrating the configuration of a CdTe solar cell. FIG. 3 is a diagram showing the relationship between the value of y and the resistance change ratio.

Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be arbitrarily modified and carried out without departing from the gist of the present invention. Further, "-" indicating a numerical range is used in the sense that the numerical values described before and after the numerical range are included as the lower limit value and the upper limit value. In the present specification, the weight-based ratio (percentage, etc.) is the same as the mass-based ratio (percentage, etc.).

<Glass substrate with film>
FIG. 1 is a schematic cross-sectional view illustrating the configuration of a glass substrate with a film according to the present embodiment. The glass substrate 1 with a film according to the present embodiment includes a glass substrate 10, an undercoat layer 20, and a functional transparent film 30 in this order. The undercoat layer 20 is a SiO _{x Cy} layer, and the value of x is 1.59 to 1.90 and the value of _y is 0.10 in SiO _{x Cy constituting the SiO x Cy layer} . It is about 0.40.

(Undercoat layer)
In the present embodiment, the undercoat layer is a SiO _{x Cy} layer. The SiO _{x Cy} layer is a layer substantially composed of SiO _{x Cy} , but may contain impurities inevitably contained at the time of production or the like. Here, in SiO _x Cy constituting the SiO _{x Cy} layer, the value of _x is 1.59 to 1.90, and the value of _y is 0.10 to 0.40.
When the value of x and the value of y are in the above ranges, the glass substrate with a film according to the present embodiment is excellent in heat resistance in a high temperature environment and also excellent in light transmission.

The value of x represents the degree of oxidation of Si. When the degree of oxidation is low, the light absorption rate increases and the light transmittance decreases. Therefore, from the viewpoint of transmittance, the value of x is 1.59 or more, preferably 1.65 or more, and more preferably 1.70 or more. Further, the sum of the value of x and the value of y generally takes a value smaller than 2. Therefore, from the viewpoint of introducing the required C, x is 1.90 or less, more preferably 1.85 or less.
The value of y represents the content of C and correlates with the refractive index. From the viewpoint of improving the refractive index, the value of y is 0.10 or more, more preferably 0.15 or more. The value of y is 0.40 or less, preferably 0.35 or less, more preferably 0.30 or less, still more preferably 0.25 or less, from the viewpoint of improving heat resistance.

In the SiO _{x Cy} layer, in order to suppress the diffusion of carbon into the functional transparent film in a high temperature environment and improve the heat resistance, the carbon content ratio in the SiO _{x Cy} layer, that is, the value of y is set. It is possible to make it smaller. However, if the value of y becomes too small, the refractive index of the SiO _{x Cy} layer changes, the difference in refractive index from the functional transparent film increases, and the light transmittance of the glass substrate with a film decreases. Therefore, when the undercoat layer is a SiO _{x Cy} layer, there is a trade-off relationship between heat resistance in a high temperature environment and light transmission.

On the other hand, the present invention has found that by adjusting the value of x and the value of y within the above range, a glass substrate with a film having both excellent heat resistance and light transmittance can be obtained. be.

The refractive index of the glass substrate is about 1.4 to 1.5. On the other hand, the refractive index of the functional transparent film varies depending on its composition, but is about 2 in the case of a film containing a metal oxide as a main component. In the present embodiment, the refractive index of the SiO _{x Cy} layer is about 1.54 to 1.75, and the difference in refractive index between the glass substrate and the functional transparent film is small, which is an intermediate value. It is possible to suppress the reflection of light in the glass substrate. Therefore, the glass substrate with a film according to this embodiment has excellent light transmission.

Further, the refractive index of the SiO _{x Cy} layer changes by adjusting the composition ratio. Here, the refractive index can be lowered by reducing the ratio represented by y / x. On the contrary, the refractive index can be increased by increasing the ratio represented by y / x. Therefore, while keeping the value of x and the value of y within the above ranges, the composition of the SiO _{x Cy} layer is further adjusted according to the specific refractive indexes of the glass substrate and the functional transparent film in order to improve the light transmission. It is also preferable to do so. The composition of the SiO _{x Cy} layer can be identified by X-ray photoelectron spectroscopy (XPS) or secondary ion mass spectrometry (SIMS). In a state where a functional transparent film or another layer is formed on the SiO _{x Cy} layer, the composition is identified after the upper layer is etched and removed with hydrochloric acid or the like. By performing XPS measurement while performing ion sputtering, the composition can be identified more accurately.

In the glass substrate with a film according to the present embodiment, the average light transmittance at a wavelength of 400 to 800 nm is preferably 80% or more, more preferably 80.5% or more, still more preferably 81% or more. When the glass substrate with a film is used as a transparent electrode of a solar cell, the loss of light energy when light passes through the transparent electrode can be reduced and the battery efficiency can be improved when the light transmittance is in the above range. Therefore, it is preferable. Low-E glass is also preferable because it may require high light transmittance, and it is also preferable because it is possible to adjust the appearance such as color tint and color unevenness. The higher the light transmittance, the more preferable, but generally the upper limit is about 85%. Since the glass substrate with a film according to the present embodiment suppresses light reflection at the interface between the film and the glass substrate, it is excellent in light transmission.

The thickness of the SiO _{x Cy} layer is preferably 10 nm or more, more preferably 20 nm or more, and even more preferably 25 nm or more from the viewpoint of sufficient coverage. Further, from the viewpoint of suppressing the absorption of light by the SiO _{x Cy} layer, the thickness is preferably 90 nm or less, more preferably 80 nm or less, still more preferably 70 nm or less.
The thickness of the SiO _{x Cy} layer can be determined by X-ray photoelectron spectroscopy (XPS) or spectroscopic ellipsometry.

(Functional transparent film)
The functional transparent film may have at least one of conductivity and low radiation characteristics depending on the application. However, since the functional transparent film having low radiation characteristics corresponds to a metal film such as silver or a metal oxide film such as SnO ₂ or ZnO ₂ , it generally has conductivity.
When the glass substrate with a film is used as a transparent electrode for a solar cell, the specific resistance of the functional transparent film is preferably 0.001 Ωcm or less, more preferably 0.0008 Ωcm or less, still more preferably 0.0006 Ωcm or less. Further, the lower the specific resistance of the functional transparent film, the more preferable, but 0.0001 Ωcm or more is practical. In the present specification, the specific resistance (R _t ) of the functional transparent film can be measured by a method using a Hall effect measuring device with respect to a glass substrate with a film.

When a glass substrate with a film is used as Low-E glass, the emissivity value of the functional transparent film is preferably 0.25 or less, more preferably 0.20 or less. Further, the lower the emissivity of the functional transparent film, the more preferable, but 0.05 or more is practical.

The film thickness of the functional transparent film is preferably 800 nm or less, more preferably 600 nm or less, from the viewpoint of ensuring high transmittance. Further, from the viewpoint of not increasing the resistance too much, 300 nm or more is preferable, and 400 nm or more is more preferable. The film thickness of the functional transparent film can be measured by using a stylus type step meter or a fluorescent X-ray analyzer.

Further, when a glass substrate with a film is used as a transparent electrode substrate for a solar cell, sheet resistance is important as an electrical characteristic of the functional transparent film. This is the electrical resistance as a substantial electrode film defined by specific resistance / film thickness. By adjusting the above-mentioned specific resistance and film thickness, the sheet resistance can be set to a preferable value. In this case, the sheet resistance is preferably 20Ω / □ or less, and more preferably 12Ω / □ or less, from the viewpoint of reducing the voltage loss in wiring.

When the glass substrate with a film is placed in a high temperature environment, the carbon of the SiO _{x Cy} layer diffuses into the functional transparent film, and the carbon reduces the conductive substances and low-radiative substances in the functional transparent film. Typically, the sheet resistance of the functional transparent film increases and the conductivity decreases. The decrease in conductivity is a factor that deteriorates the battery characteristics of the solar cell. Further, when the glass substrate with a film is made of Low-E glass, the reduction of the low-emissivity substance causes the inferiority of the low-emissivity characteristics.

That is, when (sheet resistance value after heating) / (sheet resistance value before heating) is the resistance change ratio before and after heating, and the heating conditions are 650 ° C. for 116 minutes under a nitrogen atmosphere, the resistance change ratio is 20 or less. Is preferable, 5 or less is more preferable, and 2 or less is further preferable. The smaller the resistance change ratio is, the more preferable it is, but it is usually 1 or more.

When the resistance change ratio is within the above range, it is preferable because the deterioration of the performance of the functional transparent film can be suppressed especially when the glass substrate with a film is placed in a high temperature environment of 600 ° C. or higher. In such cases, for example, a glass substrate with a film is used as a transparent electrode of a solar cell such as a CdTe solar cell that requires a process at a high temperature during its manufacture, or a glass substrate with a film is used as Low-E glass. , The case where the Low-E glass is heat-strengthened in a high temperature environment and the like can be mentioned.

When a glass substrate with a film is used as a transparent electrode substrate for a solar cell, a conventionally known functional transparent film exhibiting conductivity and translucency can be used. For example, as the main component of the functional transparent film, SnO ₂ , ZnO, and In ₂ O ₃ are preferable, SnO ₂ or ZnO is more preferable, and SnO ₂ is further preferable. In the functional transparent film, the main component means that the content of the component is 50% by weight or more with respect to all the components constituting the film, and is 70% by weight or more. Is preferable, and 85% by weight or more is more preferable. The upper limit is not particularly limited, but when the dopant is doped in the main component, 99.9% by weight or less is preferable.

Examples of the dopant include fluorine, boron, tin and the like. Examples of the doped film include fluorine-doped SnO ₂ , Sn-doped In ₂ O ₃ , fluorine-doped In ₂ O ₃ , antimony-doped SnO ₂ , Al-doped ZnO, and Ga-doped. ZnO and the like can be mentioned. It is preferable to dope the dopant because conductive carriers are generated and the resistance is low.

The functional transparent film may be composed of only one layer exhibiting at least one of conductive and low radiation properties and a translucent layer, and may further have another layer having other functions. It may be, and is not particularly limited. For example, when a glass substrate with a film is used as a transparent electrode substrate for a solar cell, it is also preferable that the functional transparent film has a configuration in which a conductive layer and a surface layer are included in this order from the glass substrate side.

As an example, in the power generation principle of a CdTe solar cell, light energy such as sunlight is incident from the transparent electrode substrate side, light is absorbed by the p-type layer, and carriers such as electrons and holes (holes) are generated. It depends. That is, the generated carriers move to the p-type layer and the n-type layer and flow, so that they are taken out as electrical energy.

However, in the above-mentioned type of solar cell (super straight type solar cell) in which a transparent conductive film, a power generation layer (battery layer), and a back surface electrode are formed in order on the transparent substrate and sunlight is incident from the transparent substrate side. , N-type layer, that is, electrons taken out in the direction of the cathode are trapped at the impurity level on the cathode surface, that is, the surface of the transparent electrode substrate, and a phenomenon (carrier recombination) occurs in which the electrons are recombined with the holes in the battery. , Battery efficiency may decrease.
Specifically, for example, when a dopant is doped in the main component of the functional transparent film, carrier recombination may occur due to the dopant level. From the viewpoint of suppressing this, it is preferable to provide a surface layer having a small dopant level on the surface of the transparent electrode substrate.

The surface layer is not particularly limited as long as it has translucency as a transparent electrode substrate and can suppress carrier recombination, but an oxide is preferable, and a metal oxide is more preferable. Specifically, SnO ₂ , ZnO, In ₂ O ₃ , TIO ₂ , CdO and the like are preferable, and a layer containing these as a main component is more preferable. The main component of the surface layer means that it is 50% by weight or more of the components constituting the surface layer, preferably 70% by weight or more, and 85% by weight or more with respect to the entire surface layer. Is more preferable. Further, the upper limit is not particularly limited.

The main component of the surface layer is more preferably SnO ₂ or ZnO, and even more preferably SnO ₂ . Although it is possible to use the same oxide as the main component of the conductive layer as the surface layer, it is preferable that the layer does not contain a dopant. That is, SnO ₂ or ZnO containing no dopant is more preferable, and SnO ₂ containing no dopant is particularly preferable.
The composition of the surface layer can be identified by X-ray photoelectron spectroscopy (XPS) or secondary ion mass spectrometry (SIMS).

The thickness of the surface layer is preferably 80 nm or less, more preferably 60 nm or less, because if it is too thick, the resistance increases and there is a risk of hindering electron transfer, which is a function of the electrode. On the other hand, from the viewpoint of sufficiently obtaining the effect of preventing carrier recombination, the thickness of the surface layer is preferably 10 nm or more, more preferably 20 nm or more. The thickness of the surface layer can be measured by a stylus type step meter, a fluorescent X-ray analyzer, X-ray photoelectron spectroscopy (XPS), or secondary ion mass spectrometry (SIMS).

The preferable component constituting the conductive layer is the same as the above-mentioned functional transparent film when used as a transparent electrode substrate for a solar cell. Further, the preferable dopant when the dopant is doped, the preferable configuration of the doped film, and the like are the same as described above. The film thickness of the conductive layer is preferably 220 nm or more, more preferably 300 nm or more. The film thickness of the conductive layer is preferably 790 nm or less, more preferably 700 nm or less.

As an example of a specific preferable configuration in which the functional transparent film has a conductive layer and a surface layer in this order from the glass substrate side, fluorine-doped SnO ₂ is used as the conductive layer and the dopant is doped. An example is a configuration in which SnO ₂ which is not used is used as a surface layer.

When a glass substrate with a film is used as Low-E glass, a conventionally known functional transparent film exhibiting low radiation characteristics and translucency can be used. For example, it is preferably composed of a metal film and a protective film for protecting the metal film, or a metal oxide film. As the metal film, for example, a film such as Ag is preferable. Further, the protective film in that case is preferably ZnO, SnO ₂ , or the like. As the metal oxide film, for example, the main components are preferably SnO ₂ , ZnO, and In ₂ O ₃ , more preferably SnO ₂ or ZnO, further preferably SnO ₂ , and these may be doped with a dopant. .. The main component of the film means the same as the main component of the functional transparent film when the glass substrate with a film is used as a transparent electrode substrate for a solar cell.
Further, as the dopant when the dopant is doped, the same dopant as that used for the functional transparent film when the glass substrate with a film is used as a transparent electrode substrate for a solar cell can be used, but for example, fluorine at a high concentration can be used. Examples thereof include doped SnO ₂ and antimony-doped SnO ₂ .
The composition of the functional transparent film can be identified by X-ray photoelectron spectroscopy (XPS) or secondary ion mass spectrometry (SIMS).

(Glass substrate)
As the glass substrate, a glass substrate for a transparent electrode substrate for a solar cell or a glass substrate similar to that used for Low-E glass can be used. For example, a glass substrate containing SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , MgO, CaO, SrO, BaO, ZrO ₂ , Na ₂ O and K ₂ O as a matrix composition can be mentioned. More specifically, in the oxide-based molar percentage display, SiO ₂ is 60 to 75%, Al ₂ O ₃ is 1 to 7.5%, B ₂ O ₃ is 0 to 1%, and MgO is 8.5. ~ 12.5%, CaO ~ 1 ~ 6.5%, SrO 0 ~ 3%, BaO 0 ~ 3%, ZrO ₂ 0 ~ 3%, Na ₂ O 1 ~ 8%, K ₂ O Examples thereof include a glass substrate containing 2 to 12%. However, the composition is not limited to these.

Considering the power generation efficiency of the solar cell and the translucency of the Low-E glass, the glass substrate preferably has an average transmittance of 90.3% or more in terms of 2 mm thickness for light having a wavelength of 500 to 800 nm, 90.4. % Or more is more preferable, and 90.5% or more is further preferable.

Further, it is preferable that the glass substrate has good heat resistance because it may be exposed to a high temperature environment or heat-treated when manufacturing a solar cell or Low-E glass.
Specifically, the glass transition temperature (Tg) is preferably 640 ° C. or higher, more preferably 660 ° C. or higher, and even more preferably 680 ° C. or higher. On the other hand, the glass transition temperature is preferably 850 ° C. or lower, more preferably 800 ° C. or lower, and even more preferably 780 ° C. or lower so as not to increase the viscosity at the time of melting too much.

The average coefficient of thermal expansion of the glass substrate at 50 to 350 ° C. is preferably 70 × 10 ^-7 / ° C. or higher, preferably 80 × 10 ^-7 / ° C. or higher, from the viewpoint of suppressing warping of the module during modularization. Is more preferable. On the other hand, from the viewpoint of suppressing peeling and the like, 90 × 10 ^-7 / ° C. or less is preferable, and 85 × 10 ^-7 / ° C. or less is more preferable.

The thickness of the glass substrate is not particularly limited, but is preferably 0.7 mm or more, more preferably 1.1 mm or more, preferably 6.0 mm or less, and preferably 4.0 mm or less from the viewpoint of strength and light transmittance. More preferred.

<Manufacturing method of glass substrate with film>
The glass substrate 1 with a film is obtained by laminating a SiO _{x Cy} layer as an undercoat layer 20 and a functional transparent film 30 in order on the glass substrate 10. At this time, if the value of x is 1.59 to 1.90 and the value of _y is 0.10 to 0.40 in SiO _x Cy of the SiO _{x Cy} layer, the manufacturing method is not particularly limited.

As the method for manufacturing the glass substrate with a film according to the present embodiment, for example, the following method is preferable.
That is, the glass substrate heated to a temperature of 500 to 800 ° C. is reacted with the gas raw material to form an undercoat layer on the glass substrate (undercoat layer forming step).
A manufacturing method including forming a functional transparent film on the undercoat layer (functional transparent film forming step) is preferable.
Here, the undercoat layer is a SiO _{x Cy} layer, the gas raw material contains a silicon-containing substance, an oxidizing agent, and an unsaturated hydrocarbon, and the volume ratio of the oxidizing agent to the silicon-containing substance is 8.5 to. It is preferably 50, and the volume ratio of the unsaturated hydrocarbon to the silicon-containing substance is preferably 0.5 to 3.5.

Hereinafter, a method for manufacturing a glass substrate with a film according to the present embodiment will be specifically described.
For the glass substrate, for example, a melting step of heating a glass raw material to obtain molten glass, a clarification step of removing bubbles from the molten glass, a molding step of forming a molten glass into a plate to obtain a glass ribbon, and slowly cooling the glass ribbon to a room temperature state. It is obtained by a slow cooling step. Further, the molten glass may be formed into a block shape, slowly cooled, and then cut and polished to produce a glass substrate.

(Undercoat layer forming process)
The SiO _{x Cy} layer as the undercoat layer can be formed by a CVD (Chemical Vapor Deposition) method, a sputtering method, a chemical plating method, a wet coating method, or the like. The sputtering method is a method of forming a film on a plate-made glass substrate, and the chemical plating method is also used when making a mirror. Among them, the CVD method is preferable, and the online CVD method described later is more preferable.

In the CVD method, for example, it is preferable to react a glass substrate heated to a temperature of 500 to 800 ° C. with a gas raw material to form a SiO _{x Cy} layer on the glass substrate.
The temperature of the glass substrate is preferably 500 ° C. or higher, more preferably 600 ° C. or higher, and even more preferably 700 ° C. or higher from the viewpoint of improving the reaction rate of the CVD method. Further, the temperature of the glass substrate is more preferably 800 ° C. or lower, further preferably 760 ° C. or lower, from the viewpoint of glass softening.

The gas raw material preferably contains a silicon-containing substance, an oxidizing agent and an unsaturated hydrocarbon.

Silicon-containing substances include silanes such as monosilane (SiH ₄ ), disilane (Si ₂ H ₆ ), dichlorosilane (SiH ₂ Cl ₂ ), silane trioxide (SiHCl ₃ ), and tetramethylsilane ((CH ₃ ) ₄ ). Alkylated silanes such as Si), silicon tetrafluoride (SiF ₄ ), silicon tetrachloride (SiCl ₄ ) and the like can be mentioned, with silanes being preferred, and monosilanes being more preferred.

Examples of the oxidizing agent include compounds containing oxygen elements such as carbon dioxide (CO ₂ ), carbon monoxide (CO), oxygen (O ₂ ), and water vapor (H ₂ O), and carbon dioxide is preferable.

Examples of the unsaturated hydrocarbon include an ethylene-based unsaturated hydrocarbon (olefin), an acetylene-based unsaturated hydrocarbon, and an aromatic compound, and a compound that is a gas at normal temperature and pressure is preferable.
As the unsaturated hydrocarbon, an olefin is preferable, an olefin having 2 to 4 carbon atoms is more preferable, and ethylene is further preferable.

For example, in a gaseous raw material, it is preferable that the silicon-containing substance contains silane, the oxidizing agent contains carbon dioxide, and the unsaturated hydrocarbon contains ethylene.

By adjusting the mixing ratio of the gas raw material, the composition of SiO _{x Cy} in the SiO _{x Cy} layer can be adjusted.
Specifically, the volume ratio of the oxidizing agent to the silicon-containing substance is preferably 8.5 or more, more preferably 12 or more, and even more preferably 20 or more. The volume ratio of the oxidizing agent to the silicon-containing substance is preferably 50 or less.

The volume ratio of unsaturated hydrocarbon to silicon-containing substance is preferably 0.5 or more, more preferably 1.0 or more. The volume ratio of unsaturated hydrocarbons to silicon-containing substances is preferably 3.5 or less, more preferably 2.7 or less.

The composition of SiO _{x Cy} changes due to the interaction of the above-mentioned oxidizing agent and unsaturated hydrocarbon. Therefore, in order to adjust the composition of SiO _{x Cy} to a preferable range, a combination of both the volume ratio of the oxidizing agent to the silicon-containing substance and the volume ratio of the unsaturated hydrocarbon is important, and both are preferable as described above. The range is particularly preferable.

The thickness of the SiO _{x Cy} layer is preferably 10 nm or more, more preferably 20 nm or more, and even more preferably 25 nm or more from the viewpoint of sufficient coverage. Further, from the viewpoint of suppressing the absorption of light by the SiO _{x Cy} layer, the thickness is preferably 90 nm or less, more preferably 80 nm or less, still more preferably 70 nm or less. The thickness of the SiO _{x Cy} layer can be controlled by the type of raw material, the concentration of raw material gas, the flow rate of blowing the raw material gas onto the glass ribbon or the glass substrate, the substrate temperature, the residence time of the reaction gas derived from the coating beam structure, and the like.

(Functional transparent film forming process)
The production method according to the present embodiment includes forming a functional transparent film on the above-mentioned undercoat layer. The formation of the functional transparent film may be made by using conventionally known methods, and is not particularly limited. Similar to the SiO _{x Cy} layer, the functional transparent film can be formed by a CVD (Chemical Vapor Deposition) method, a sputtering method, a chemical plating method, a wet coating method, or the like. Among them, the CVD method is preferable, and the online CVD method described later is more preferable. When the functional transparent film includes a conductive layer and a surface layer, the conductive layer and the surface layer may be formed on the SiO _{x Cy} layer in this order.

The online CVD method is a kind of CVD method, and is a method of forming a film directly on the surface of glass during the manufacturing process of a glass substrate on a float line. That is, instead of forming the undercoat layer and the functional transparent film after obtaining the cut glass substrate, the undercoat layer and the functional transparent film are formed in the middle of the process of obtaining the glass substrate.
Specifically, when the glass substrate is manufactured, the glass ribbon moves on the molten tin bath and then is slowly cooled to continuously manufacture the glass substrate. During the movement of the glass ribbon, the glass substrate is continuously manufactured. , The process of forming an undercoat layer and a functional transparent film is continuously carried out on the upper surface of the glass ribbon.

More specifically, in the above-mentioned method for manufacturing a glass substrate, a gas raw material is sprayed onto the glass surface and reacted while the glass is still hot between the float line of the molding process and the slow cooling process. A glass substrate with a film can be obtained by forming a coat layer and a functional transparent film.
The online CVD method is preferable because the undercoat layer and the functional transparent film can be formed in a series of steps for manufacturing the glass substrate, and thus the manufacturing cost can be kept low. In this case, since the film is formed online, the composition of the layer to be formed is limited. For example, when a glass substrate with a film is used as a transparent electrode substrate for a solar cell, the undercoat layer is a SiO _{x Cy} layer, and the functional transparent film is a film containing fluorinated SnO ₂ as a main component. Is mentioned as a preferable embodiment. When the glass substrate with a film is used as Low-E glass, the undercoat layer is a SiO _{x Cy} layer, and the functional transparent film is a high-concentration fluorine-doped SnO ₂ or an antimon-doped SnO ₂ . A preferred embodiment is to use a film as a main component.

On the other hand, the offline CVD method is also a kind of CVD method, and is different from the online CVD method while transporting a glass substrate once manufactured by a glass manufacturing process and cut to an appropriate size into an electric furnace again. Similarly, it is a method of forming an undercoat layer and a functional transparent film by utilizing the reaction of a gas raw material. Although there is an advantage that the transfer speed and the substrate temperature can be set according to the film formation, the manufacturing cost is higher than that of the online CVD method.

When the sputtering method is used, a very small amount of special gas is injected into a vacuumed container and a voltage is applied to a suitable sputtering target to form an undercoat layer and a functional transparent film on a glass substrate. A glass substrate with a film can be obtained.
Since the sputtering method forms a layer on a glass substrate once made into a plate, it is possible to form a layer having various desired compositions, although the manufacturing cost is high.

In the case of the CVD method, the thickness of the undercoat layer and the functional transparent film is the type of raw material, the concentration of raw material gas, the moving speed of the glass ribbon or the glass substrate itself, the flow rate of spraying the raw material gas onto it, the substrate temperature, and the coating. It can be controlled by the residence time of the reaction gas derived from the beam structure. Further, in the case of the sputtering method, the thickness can be controlled by the sputtering time, voltage and the like.
The above-mentioned manufacturing method is not limited to the embodiment, and can be appropriately modified or improved as long as the object of the present invention can be achieved.

<Solar cell>
The present invention relates to a solar cell having the glass substrate with a film as a transparent electrode substrate. The glass substrate with a film according to the present embodiment described above is particularly suitable for a wide range of the transparent electrode substrates for solar cells of the super straight type. The configuration and preferred embodiment of the transparent electrode substrate are the same as those described in the above <Glass substrate with film>.
The solar cell of the present invention is preferably a super straight type solar cell, more preferably a solar cell that undergoes heat treatment at a high temperature such as annealing treatment or high temperature film formation in the manufacturing process thereof, and examples thereof include a CdTe solar cell. However, it does not exclude the application to other solar cells.
As shown in FIG. 2, the CdTe solar cell 2 has an n-type layer 40, a p-type layer 50, and a back surface electrode (anode) 60 on the surface of a functional transparent film 30 of a glass substrate with a film to be a transparent electrode substrate. Are stacked in order.

In the case of a CdTe solar cell, an n-type layer is formed on the surface opposite to the undercoat layer in the functional transparent film of the transparent electrode substrate, but a conventionally known n-type layer can be used. For example, CdS, CdSe and the like can be mentioned, and CdS is preferable.
The thickness of the n-type layer is preferably 30 nm or more, and preferably 100 nm or less.
The n-type layer can be formed by the proximity sublimation method, and its thickness and film quality can be adjusted by changing the sublimation rate or the substrate temperature.

CdTe is generally used for the p-type layer. The thickness of the p-type layer is preferably 3 μm or more, and preferably 15 μm or less.
The p-type layer can be formed by the proximity sublimation method, and its thickness and film quality can be adjusted by changing the sublimation rate or the substrate temperature.

The back electrode acts as an anode. As the back surface electrode, conventionally known ones can be used. For example, an electrode having a structure in which a metal material film such as silver (Ag) or molybdenum (Mo) is laminated, a carbon electrode doped with Cu, and the like can be mentioned. Further, the back plate glass may be further provided on the back surface electrode. The back plate glass may have water resistance and oxygen permeability resistance, and a back film made of resin may be used instead of the back plate glass.
The back surface electrode and the back plate glass or the back film are bonded with a resin for encapsulation or adhesion.
The thickness of the back surface electrode is preferably 100 nm or more, and preferably 1000 nm or less. The thickness of the back plate glass or the back film is preferably 1 mm or more, and preferably 3 mm or less.

The end of the p-type layer made of CdTe or the end of the CdTe solar cell may be sealed. Examples of the material for sealing include glass having the same composition as the glass substrate in the transparent electrode substrate, glass having another composition, resin and the like.

<Low-E glass>
The present invention relates to Low-E glass made of the above-mentioned glass substrate with a film. The configuration and preferred embodiment of the Low-E glass are the same as those described in the above <Glass substrate with film>.
That is, a SiO _{x Cy} layer and a functional transparent film are formed on the surface of the glass substrate in this order. As the functional transparent film, a conventionally known material can be used, for example, a metal film and a protective film thereof. It may be composed of a protective film and a metal oxide film.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. Examples 1 to 6 are examples, and examples 7 to 9 are comparative examples.

[Example 1]
As shown below, a glass substrate with a film was obtained by producing a glass substrate by the float method and at the same time forming an undercoat layer and a functional transparent film by the online atmospheric pressure CVD (chemical vapor deposition) method.

Fused glass having a soda lime silica glass composition was poured into a float bath at 1500 to 1600 ° C., and a plate-shaped glass was formed while continuously flowing a glass ribbon.
(Formation of SiO _{x Cy} layer)
From the first coating beam located on the most upstream side where the temperature of the glass ribbon is 760 ° C, monosilane (SiH ₄ ) 0.364 kg / hour, ethylene 0.25 kg / hour, CO ₂ gas 12.5 kg / hour as a gas raw material For hours, 1.0 kg / hour of nitrogen gas was supplied, and a SiO _{x Cy} layer having a film thickness of 50 nm was formed on the glass ribbon. The volume ratio of ethylene to monosilane (hereinafter, "C ₂ H ₄ ratio") and the volume ratio of CO ₂ gas to monosilane (hereinafter, "CO ₂ ratio") in the gas raw material, and the obtained SiO _{x Cy} layer. The values of x and y are shown in Table 1.

(Formation of functional transparent film)
Subsequently, a mixed gas consisting of monobutyltin trichloride, air, water, nitrogen, nitrate and trifluoroacetic acid is supplied from a second coating beam located on the downstream side where the glass ribbon reaches 615 ° C., and the film thickness is 430 nm. SnO ₂ : A functional transparent film (fluorine-doped tin oxide film) containing F as a main component was formed. In the mixed gas, each substance was supplied to a mixer in a liquid phase state or a gas phase state, and mixed while being heated and vaporized there to obtain a mixed gas. The amount of each raw material supplied from the second coating beam was monobutyltin trichloride 25.2 L / hour (liquid phase), air 171.7 Nm ³ / hour, water 96.0 kg / hour, nitrogen 60.3 Nm ³ / hour. , 22.3 L / hour (liquid phase) of an aqueous nitrogen solution having a concentration of 66.5 wt%, and 5.3 L / hour (liquid phase) of trifluoroacetic acid. The thickness of the glass substrate with a film was 3.2 mm.

[Examples 2 to 8]
The amount of each raw material supplied from the first coating beam was changed so that the _C2H4 ratio and the _CO2 ratio _were the values shown in Table 1, and SiO was formed on the glass ribbon with the film thickness shown in Table 1. A glass substrate with a film was obtained in the same manner as in Example 1 except that the _{xCy layer} was formed.
In each example, the values of x and _y of the obtained SiO _x Cy layer are shown in Table 1.

[Example 9]
In Example 9, the SiO _{x Cy} layer is a SiO ₂ layer having x = 2 and y = 0. From the first coating beam, monosilane (SiH ₄ ) 0.425 kg / hour, ethylene 0.56 kg / hour, O ₂ gas 35.3 kg / hour, nitrogen gas 60.9 kg / hour are supplied as gas raw materials, and a glass ribbon is supplied. A SiO _{x Cy} layer (SiO ₂ layer) having a film thickness of 30 nm was formed on the film.
However, at this time, the O ₂ gas was sprayed from a slit different from that of the other raw materials so as to be mixed with the other raw materials directly on the substrate to form a film of the SiO _{x Cy} layer.
A glass substrate with a film was obtained in the same manner as in Example 1 except for the above. The column of "CO ₂ ratio" in Table 1 shows the volume ratio (O ₂ ratio) of O ₂ gas to monosilane in the gas raw material for Example 9.

For the glass substrate with a film of each example, x and y were identified and the light transmittance and the heat resistance at 650 ° C. were evaluated under the following conditions.
(Identification of x and y)
The composition of the SiO _{x Cy} layer was identified by an X-ray photoelectron spectrometer (XPS) PHI5000 VersaProbe (manufactured by ULVAC-PHI).
The specific measurement procedure is shown below. First, the glass substrate with a film was melt-etched using an aqueous hydrochloric acid solution and zinc powder to remove the functional transparent film. After washing with water with an ultrasonic cleaner and drying, X-ray photoelectron spectroscopy measurement was performed by the XPS at an X-ray output under the conditions of 100 μmφ, 25 W, and 15 kV. In the measurement, while performing Ar ion sputtering at an incident angle of 45 °, the photoelectron intensities of C1s, O1s, and Si2s in the film thickness direction were detected, and a composition distribution profile in the thickness direction was obtained. The data is based on the obtained composition distribution profile, from the surface to the point where the C / Si (atomic number ratio) value decreases to 0.02 or less, in the range where the SiO _{x Cy} layer is formed. Treated as (film thickness). Table 1 shows the calculated average value of the entire layer with O / Si (atomic number ratio) as the value of x and C / Si (atomic number ratio) as the value of y.

(Film thickness of SiO _{x Cy} layer)
The glass substrate with a film was melt-etched using an aqueous hydrochloric acid solution and zinc powder to remove the functional transparent film. After washing with water with an ultrasonic cleaner and drying, the film thickness of the SiO _x Cy layer was measured using spectroscopic ellipsometry M-200I (manufactured by JA _Woollam ).

(Light transmittance)
Using a spectrophotometer Lambda950 (manufactured by Parkin Elmer), the measured light is incident on the glass substrate with a film from the glass substrate side, and the transmittance is measured every 2 nm in the wavelength range of 300 to 1280 nm, and the wavelength is 400. The average value of each transmittance in the range of about 800 nm was used as the representative value of the transmittance. The results are shown in Table 1.

(650 ° C heat resistance (resistance change ratio))
A glass substrate with a film was cut into a size of 1 cm square, and a Hall effect measuring device (HL5500PC manufactured by Accent Optical Technologies) was used to first measure the sheet resistance value before heating. Next, a conveyor belt conveyor furnace (manufactured by DENKO) was set at 650 ° C. and heated at a speed of 11.2 mm / min for 116 minutes. In the furnace, nitrogen was continuously supplied to maintain an atmosphere having an oxygen concentration of 10 ppm or less. After heating, the sheet resistance value (sheet resistance value after heating) is measured again by the same method as described above, and from those results, the table is expressed as (sheet resistance value after heating) / (sheet resistance value before heating). The value to be obtained was determined as 650 ° C. heat resistance (resistance change ratio). The value of heat resistance (resistance change ratio) at 650 ° C. is usually 1 or more, but the smaller the value and the closer to 1, it means that the glass substrate with a film has excellent heat resistance. On the other hand, if this value exceeds 20, the performance in each application is significantly deteriorated, which is very unfavorable. The results are shown in Table 1. Further, for Examples 1 to 9, the relationship between the value of y and the resistance change ratio is shown in FIG.

As shown in Table 1, the film-coated glass substrates of Examples 1 to 6 having a SiO _{x Cy} layer in which the x value and the y value are adjusted to a specific range as the undercoat layer are 80% or more high. It was possible to achieve both light transmittance and excellent heat resistance. On the other hand, the glass substrates with a film of Examples 7 and 8 were inferior in heat resistance because the value of y was too large. Further, the glass substrate with a film of Example 9 was inferior in light transmittance because the value of y was too small.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on a Japanese patent application filed on November 30, 2020 (Japanese Patent Application No. 2020-198863), the contents of which are incorporated herein by reference.

The glass substrate with a film according to the present invention has excellent heat resistance and light transmission, and is therefore very useful as a transparent electrode substrate for solar cells and Low-E glass. Since the glass substrate with a film according to the present invention can suppress deterioration of the performance of the functional transparent film, particularly when placed in a high temperature environment of 600 ° C. or higher, a process at a high temperature is required at the time of manufacturing the CdTe solar cell or the like. It is particularly suitable for transparent electrodes for solar cells and Low-E glass when heat-strengthening treatment is performed in a high temperature environment.

1 Glass substrate with film 2 CdTe solar cell 10 Glass substrate 20 Undercoat layer 30 Functional transparent film 40 n-type layer 50 p-type layer 60 Back electrode

Claims (9)

A glass substrate with a film containing a glass substrate, an undercoat layer, and a functional transparent film in this order.
The undercoat layer is a SiO _{x Cy} layer, and the undercoat layer is a SiO x Cy layer.
A glass substrate with a film having a value of x of 1.59 to 1.90 and a value of _y of 0.10 to 0.40 in SiO _{x Cy constituting the SiO x Cy layer} . The glass substrate with a film according to claim 1, wherein the undercoat layer has a thickness of 10 to 90 nm. The glass substrate with a film according to claim 1 or 2, wherein the main component of the functional transparent film is SnO ₂ . The glass substrate with a film according to any one of claims 1 to 3, wherein the functional transparent film includes a conductive layer and a surface layer in this order from the glass substrate side. A solar cell having the glass substrate with a film according to any one of claims 1 to 4 as a transparent electrode substrate. Low-E glass made of the glass substrate with a film according to any one of claims 1 to 3. It is a method of manufacturing a glass substrate with a film.
By reacting a glass substrate heated to a temperature of 500 to 800 ° C. with a gas raw material to form an undercoat layer on the glass substrate,
Including forming a functional transparent film on the undercoat layer.
The undercoat layer is a SiO _{x Cy} layer, and is
The gaseous raw material contains a silicon-containing substance, an oxidizing agent and an unsaturated hydrocarbon, and contains
The volume ratio of the oxidizing agent to the silicon-containing substance is 8.5 to 50, and the volume ratio is 8.5 to 50.
The volume ratio of the unsaturated hydrocarbon to the silicon-containing substance is 0.5 to 3.5.
A method for manufacturing a glass substrate with a film. The method for producing a glass substrate with a film according to claim 7, wherein the silicon-containing substance contains silane, the oxidizing agent contains carbon dioxide, and the unsaturated hydrocarbon contains ethylene. The method for manufacturing a glass substrate with a film according to claim 7 or 8, wherein the thickness of the undercoat layer is 10 to 90 nm.

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