JP7020458B2 - Glass substrate with film and its manufacturing method - Google Patents

Description

The present invention relates to a glass substrate with a film and a method for manufacturing the same, and more 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.

However, alkaline ions diffuse from the glass substrate due to heat treatment at high temperature when manufacturing a solar cell or long-term use. As a result, the transparent conductive film and the metal oxide film (hereinafter referred to as functional transparent film) have a decrease in transparency, a decrease in conductivity (increase in specific resistance), a decrease in chemical and physical durability, and the like. There is a concern that performance deterioration will be caused.

Therefore, Patent Document 1 is a conductive glass in which an alkali barrier film that suppresses alkali diffusion from the glass and a conductive film are sequentially laminated on the surface of the alkali-containing glass, and the alkaline barrier film is mainly composed of tin and silicon. A conductive glass characterized by being an oxide film as a component is disclosed.

Further, Patent Document 2 discloses a base film containing silicon, oxygen and carbon as a film having barrier performance as a base film in order to prevent diffusion of an alkaline component from a glass plate to a transparent conductive film. ..

Japanese Unexamined Patent Publication No. 06-191894 Japanese Unexamined Patent Publication No. 2005-029463

However, when SiO ₂ is used as the undercoat layer for preventing the diffusion of alkali, not only the light is reflected due to the difference in the refractive index from the functional transparent film, but also the transmittance is lowered. Reflection may cause the glass to appear colored.

Further, when SiOxCy containing silicon, oxygen and carbon is used as the undercoat layer, it is placed in a high temperature environment due to the film forming process temperature when manufacturing a solar cell or the heat strengthening treatment of Low-E glass. Due to its low heat resistance, it decomposes and carbon is desorbed. Since the elements of the functional transparent film are extracted by the desorbed carbon, the composition of the functional transparent film is changed and the performance such as conductivity and thermal radiation is deteriorated. Furthermore, when exposed to harsh environments such as higher temperatures and longer periods, the undercoat layer itself breaks and peels off.

Therefore, the present invention can be used as a transparent electrode substrate for solar cells or Low-E glass, and has high transparency, that is, glass with a film having low reflectance, flexible color control, and excellent heat resistance. The purpose is to provide a substrate.

The present invention relates to the following [1] to [6].
[1] A glass substrate with a film containing a glass substrate, an undercoat layer, and a functional transparent film in this order, and the undercoat layer is composed of a SiOxCy layer and a _SiO2 layer in order from the glass substrate side. Glass substrate with a film.
[2] The glass substrate with a film according to the above [1], wherein the SiOxCy layer has a thickness of 10 to 90 nm, and the SiO ₂ 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] A solar cell having the glass substrate with a film according to any one of [1] to [3] as a transparent electrode substrate.
[5] Low-E glass comprising the glass substrate with a film according to any one of [1] to [3] above.
[6] A method for manufacturing a glass substrate with a film by using a float method, which is a melting step of heating a glass raw material to obtain molten glass, a clarification step of removing bubbles from the molten glass, and a molten glass excluding the bubbles. Including a molding step of obtaining a glass ribbon in the shape of a plate and a slow cooling step of slowly cooling the glass ribbon to room temperature, the surface of the glass ribbon is subjected to an online CVD method between the molding step and the slow cooling step. A method for manufacturing a glass substrate with a film, which comprises a film forming step of continuously forming a SiOxCy layer, a _SiO2 layer, and a functional transparent film in this order.

According to the glass substrate with a film according to the present invention, when used as a transparent electrode substrate for a solar cell or Low-E glass, the undercoat layer does not peel off even when exposed to a high temperature environment, and has high conductivity. Properties such as low radiation and high light transmission can also be maintained. Further, since the refractive index can be adjusted by changing the composition of the SiOxCy layer constituting the undercoat layer, it is possible to freely control the color of the glass substrate with a film.

FIG. 1 is a schematic cross-sectional view showing the configuration of a glass substrate with a film. FIG. 2 is a schematic cross-sectional view showing the configuration of a CdTe solar cell.

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.

<Glass substrate with film>
As shown in FIG. 1, the glass substrate 1 with a film according to the present invention includes a glass substrate 10, an undercoat layer 20, and a functional transparent film 30 in this order, and the undercoat layer 20 is the glass substrate. It is characterized in that it is composed of the SiOxCy layer 21 and the SiO ₂ layer 22 in order from the 10 side.

(Undercoat layer)
By forming the undercoat layer as a SiOxCy layer and a _SiO2 layer in order from the glass substrate side, the undercoat layer does not peel off even in a high temperature environment, and diffusion of alkali from the glass substrate is prevented. Furthermore, it is possible to prevent the reflection of light and control the color of the glass substrate with a film.

The refractive index of the glass substrate is about 1.4 to 1.5, whereas the refractive index of the functional transparent film varies depending on the composition, but in the case of a film containing a metal oxide as a main component. It is about 2. On the other hand, the refractive index of the SiOxCy layer can be easily controlled by changing the subtle difference in the carbon C content ratio (y). Therefore, it is possible to obtain a glass substrate with a film having a high transmittance by suppressing the reflection of light. Further, when it is desired to develop a color on a glass substrate with a film, the color tone can be controlled.

On the other hand, the SiOxCy layer is easily decomposed by heat, and C has a property of being easily diffused and moved under high heat conditions. In particular, it was found that in an environment of 600 ° C. or higher, C diffuses into the functional transparent film and reduces conductive substances and low radioactive substances as impurities, and as a result, has an effect of increasing sheet resistance. ..
An increase in sheet resistance in a high-temperature environment means that the resistance of the functional transparent film increases when high-temperature treatment such as in the process of manufacturing a solar cell is performed, and as a result, the characteristics of the solar cell are greatly increased. It becomes a factor such as lowering. Further, in the case of Low-glass, the low radioactive substance is reduced, which causes the low radioactivity to be inferior.

On the other hand, in the present invention, by further forming a SiO ₂ layer between the SiOxCy layer and the functional transparent film, the effects of the SiOxCy layer such as high transmittance and color control are not impaired. It is possible to suppress diffusion and realize high heat resistance.
Since the SiO ₂ layer has a finer film quality and higher coverage than the SiOxCy layer, even a layer having a very thin thickness of about 10 nm can sufficiently suppress the diffusion and movement of C. ..

Further, the SiO ₂ layer is a flat film having a refractive index of about 1.44 to 1.50. On the other hand, the SiOxCy layer has irregularities on its surface depending on the film forming conditions, and its refractive index varies greatly from 1.54 to 1.75. Therefore, laminating the SiOxCy layer and the SiO ₂ layer has an overall refractive index. And the degree of freedom to change the flatness as needed can be expanded.

In the SiOxCy layer, the refractive index can be easily changed by changing the subtle difference in the carbon C content ratio represented by y, whereby the transmittance and the tint can be controlled. In SiOxCy, the value of x can be in the range of 1.95 to 1.00 and the value of y can be in the range of 0.05 to 1.00, but the value of x is preferably 1.85 or less, and 1.20 or more. The value of y is preferably 0.15 or more, and preferably 0.80 or less. Further, 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.

The thickness of the SiOxCy layer is preferably 10 nm or more, more preferably 20 nm or more from the viewpoint of sufficient coverage. Further, 90 nm or less is preferable from the viewpoint of suppressing the light absorption rate. The thickness of the SiOxCy layer can be determined by X-ray photoelectron spectroscopy (XPS) or spectroscopic ellipsometry.

The thickness of the SiO ₂ layer is preferably 7 nm or more from the viewpoint of sufficient covering property, preferably 90 nm or less, and more preferably 50 nm or less from the viewpoint of optimizing the optical design. The thickness of the SiO ₂ 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 the properties of conductivity and low radioactivity, and the functional transparent film having low radioactivity includes a metal film such as silver, SnO ₂ , ZnO ₂ , and the like. Since the metal oxide film of the above is applicable, it also has conductivity.
When a glass substrate with a film is used as a transparent electrode for a solar cell, the resistivity 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 is, the more preferable it is, but 0.0001 Ωcm or more is practical. In the present specification, the resistivity (R _t ) of the functional transparent film can be measured by using a Hall effect measuring device for a glass substrate with a film.

When the 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, more preferably 12Ω / □ or less, from the viewpoint of reducing the voltage loss in wiring.

The functional transparent film may be composed of only one layer exhibiting at least one of conductivity and low radioactivity and a translucent layer, and may further have another layer having other functions. It may be, and is not particularly limited.
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, the main component is SnO ₂ , ZnO and In ₂ O ₃ are preferable, SnO ₂ or ZnO is more preferable, and SnO ₂ is even more preferable. The main component of the functional transparent film means that the content thereof is 50% by weight or more with respect to all the components constituting the film, and is preferably 70% by weight or more, preferably 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.

When a glass substrate with a film is used as Low-E glass, a conventionally known functional transparent film exhibiting low radioactivity 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, a high concentration can be used. Examples thereof include fluorine-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 which is 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 for light having a wavelength of 500 to 800 nm, preferably 90.3% or more in terms of 2 mm thickness. The above 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 645 ° C. or higher, and even more preferably 655 ° C. or higher. On the other hand, the glass transition temperature is preferably 750 ° C. or lower, more preferably 720 ° C. or lower, and even more preferably 690 ° 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 lower is preferable, and 85 × 10 ^-7 / ° C. or lower 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 more preferably 4.0 mm or less from the viewpoint of strength and transmittance. preferable.

<Manufacturing method of glass substrate with film>
The glass substrate 1 with a film can be obtained by sequentially laminating a SiOxCy layer 21 and a SiO ₂ layer 22 as an undercoat layer 20 and a functional transparent film 30 on the glass substrate 10.
Specifically, for the glass substrate, 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 a glass ribbon at room temperature. It can be obtained by a slow cooling step of slowly cooling to a state. Further, the molten glass may be formed into a block shape, slowly cooled, and then cut and polished to produce a glass substrate.

For each of the above steps, conventionally known methods can be used. The 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.

A SiOxCy layer and a _SiO2 layer are sequentially formed on the glass substrate as an undercoat layer, and then a functional transparent film is formed.
The undercoat layer and 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. The sputtering method is a method of forming a film on a plate-made glass substrate, and the chemical plating method is a method of making a mirror.

Among them, the CVD method is preferable, and the online CVD method described later is more preferable.
Specifically, it is a method of manufacturing a glass substrate with a film by using a float method, which is a melting step of heating a glass raw material to obtain molten glass, a clarification step of removing bubbles from the molten glass, and removing the bubbles. A molding step of forming a molten glass into a plate to obtain a glass ribbon and a slow cooling step of slowly cooling the glass ribbon to room temperature are included, and the glass ribbon is subjected to an online CVD method between the molding step and the slow cooling step. It is more preferable to include a film forming step of continuously forming a SiOxCy layer, a _SiO2 layer, and a functional transparent film in this order on the surface of the above.

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 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 sequentially a SiOxCy layer and a _SiO2 layer, and the functional transparent film is a film containing fluorinated SnO ₂ as a main component. It is mentioned as a preferable embodiment. When a glass substrate with a film is used as Low-E glass, the undercoat layer is sequentially a SiOxCy layer and a _SiO2 layer, and the functional transparent film is a high-concentration fluorine-doped SnO ₂ or an antimon-doped SnO. A preferred embodiment is a film containing ₂ 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 determined by the type of raw material, the concentration of the raw material gas, the flow velocity of the raw material gas blown onto the glass ribbon or the glass substrate, the substrate temperature, and the retention of the reaction gas derived from the coating beam structure. It can be controlled by time and the like. Further, in the case of the sputtering method, the thickness can be controlled by the sputtering time, voltage and the like.

<Solar cell>
The present invention relates to a solar cell having the glass substrate with a film as a transparent electrode substrate. 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 solar cell that is heat-treated at a high temperature such as an annealing treatment 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 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. It is a configuration in which they are stacked in order.

In the case of a CdTe solar cell, an n-type layer is formed on the surface of the transparent electrode substrate on the surface layer side, but conventionally known n-type layers can be used, and examples thereof include CdS and CdSe. Therefore, 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 a 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, but 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, the SiOxCy layer, the SiO ₂ layer, and the functional transparent film are formed in this order on the surface of the glass substrate. As the functional transparent film, a conventionally known one can be used, for example, a metal film. It may be composed of a protective film and a protective film that protects it, or it may be composed of a metal oxide film.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

[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 phase) 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.
From the first coating beam located on the most upstream side where the temperature of the glass ribbon is 700 ° C, monosilane (SiH ₄ ) 0.538 kg / hour, ethylene 1.07 kg / hour, CO ₂ gas 10.9 kg / hour, nitrogen A gas of 4.90 kg / hour was supplied, and a SiOxCy layer having a film thickness of 55 nm was formed on the glass ribbon.
Subsequently, from the second coating beam located on the downstream side where the glass ribbon reaches 620 ° C, monosilane 0.12 kg / hour, ethylene 0.36 kg / hour, CO ₂ gas 30.0 kg / hour, nitrogen gas 1.0 kg. / Time was supplied to form a SiO ₂ layer having a film thickness of 10 nm.
Further, a function of supplying a mixed gas composed of monobutyltin trichloride, oxygen, water, nitrogen, and trifluoroacetic acid from a third coating beam immediately downstream thereof, and having SnO ₂ : F having a film thickness of 400 nm as a component. A transparent transparent film (fluorine-doped tin film) was formed. In the mixed gas, each substance is supplied to a mixer in a liquid phase state or a gas phase state, and the mixed gas is mixed while being heated and vaporized there to obtain a mixed gas. The amount of each raw material supplied from the third coating beam was monobutyltin trichloride 20.5 L / hour (liquid phase), oxygen 35.7 Nm ³ / hour, water 88.6 kg / hour, trifluoroacetic acid 4.9 L / hour. It was (liquid phase). The thickness of the glass substrate with a film was 3.2 mm.

[Example 2]
The amount of each raw material supplied from the first coating beam was changed to 0.553 kg / hour for monosilane, 1.90 kg / hour for ethylene, 5.69 kg / hour for CO ₂ gas, and 10.8 kg / hour for nitrogen gas. A SiOxCy layer having a thickness of 45 nm was formed on the ribbon, and the amount of each raw material supplied from the second coating beam was 0.23 kg / hour for monosilane, 0.73 kg / hour for ethylene, and 30.0 kg / hour for CO ₂ gas. A glass substrate with a film was obtained in the same manner as in Example 1 except that the time and nitrogen gas were changed to 0.588 kg / hour and _two layers of SiO having a film thickness of 20 nm were formed.

[Comparative Example 1]
No film formation was performed from the first coating beam, and from the second coating beam, monosilane 0.12 kg / hour, ethylene 0.36 kg / hour, CO ₂ gas 30.0 kg / hour, nitrogen gas 1.0 kg / hour. A glass substrate with a film was obtained in the same manner as in Example 1 except that _two layers of SiO having a film thickness of 10 nm were formed.

[Comparative Example 2]
No film formation was performed from the first coating beam, and the amount of each raw material supplied from the second coating beam was 0.23 kg / hour for monosilane, 0.73 kg / hour for ethylene, and 30.0 kg / hour for CO ₂ gas. A glass substrate with a film was obtained in the same manner as in Example 1 except that the nitrogen gas was changed to 0.588 kg / hour and _two layers of SiO having a film thickness of 20 nm were formed.

[Comparative Example 3]
From the first coating beam, monosilane (SiH ₄ ) 0.538 kg / hour, ethylene 1.07 kg / hour, CO ₂ gas 10.9 kg / hour, nitrogen gas 4.90 kg / hour were supplied, and a film was applied onto the glass ribbon. A glass substrate with a film was obtained in the same manner as in Example 1 except that a SiOxCy layer having a thickness of 55 nm was formed and no film was formed from the second coating beam.

[Comparative Example 4]
The amount of each raw material supplied from the first coating beam was changed to 0.553 kg / hour for monosilane, 1.90 kg / hour for ethylene, 5.69 kg / hour for CO ₂ gas, and 10.8 kg / hour for nitrogen gas. A SiOxCy layer having a film thickness of 45 nm was formed on the ribbon, and a glass substrate with a film was obtained in the same manner as in Example 1 except that the film was not formed from the second coating beam.

The obtained glass substrate with a film was evaluated for transmittance, heat resistance at 650 ° C., and refractive index of the SiOxCy layer under the following conditions. The results are shown in Table 1.
(Transmittance)
Using a spectrophotometer Lambda950 (manufactured by PerkinElmer), 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.

(650 ° C heat resistance (resistance change ratio))
A glass substrate with a film was cut into a size of 1 cm square, and the sheet resistance value before heating was first measured using a Hall effect measuring device (HL5500PC manufactured by Accent Optical Technologies). Next, a transport type belt conveyor furnace (manufactured by DENKO) was set at 650 ° C., and heating was performed for 116 minutes while transporting at a speed of 11.2 mm / min. In the furnace, nitrogen was continuously supplied to maintain an atmosphere with 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, it is expressed as (sheet resistance value after heating) / (sheet resistance value before heating). The value was determined as 650 ° C. heat resistance (resistance change ratio). The value of heat resistance (resistance change ratio) at 650 ° C. is 1 or more, and the closer the value is to 1, the higher the heat resistance.

(Refractive index of SiOxCy layer)
The obtained glass substrate with a film was etched with a 10 wt% hydrochloric acid aqueous solution and zinc powder to remove a functional transparent film (fluorine-doped tin film) containing SnO ₂ : F as a component. Then, after washing with water and drying with an ultrasonic cleaner, the refractive index of the SiOxCy layer constituting the glass substrate with a film was measured using spectroscopic ellipsometry M-2000I (manufactured by JA Woollam). ..

As shown in Table 1, by using a glass substrate with a film having a SiOxCy layer and a _SiO2 layer in this order as the undercoat layer, it is possible to have excellent heat resistance while maintaining a high transmittance of 82% or more. Do you get it.

The glass substrate with a film according to the present invention has high transparency, is capable of controlling the refractive index, that is, color, and is also excellent in heat resistance. Therefore, it is extremely suitable as a transparent electrode substrate for solar cells and Low-E glass. It is useful.

1 Glass substrate with film 10 Glass substrate 20 Undercoat layer 21 SiOxCy layer 22 SiO ₂ layer 30 Functional transparent film 40 n-type layer 50 p-type layer 60 Back electrode

Claims (4)

A glass substrate with a film containing a glass substrate, an undercoat layer, and a functional transparent film in this order, wherein the undercoat layer is composed of a SiOxCy layer and a _SiO2 layer in order from the glass substrate side .
A glass substrate with a film in which the main component of the functional transparent film is SnO ₂ . A solar cell having the glass substrate with a film according to claim 1 as a transparent electrode substrate. Low-E glass comprising the glass substrate with a film according to claim 1 . It is a method of manufacturing a glass substrate with a film using the float method.
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 from which the bubbles have been removed into a plate shape to obtain a glass ribbon, and slowly cooling the glass ribbon to room temperature. Including slow cooling process to cool
Between the molding step and the slow cooling step, a film forming step of continuously forming a SiOxCy layer, a SiO ₂ layer, and a functional transparent film on the surface of the glass ribbon by an online CVD method is included. A method for manufacturing a glass substrate with a film.

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