JP2009064947A - Board heating device for thin-film solar battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a board heating device for a thin-film solar battery which has a temperature control means that controls the temperature of a film board to a target temperature based on a temperature measurement on the board to enable accurate temperature control by excluding light and heat other than radiant light and heat. <P>SOLUTION: The thin-film solar battery is made by forming at least one electrode film and one or a plurality of photoelectric conversion units on the filmlike board 10 by plasma CVD. The thin-film solar battery includes an infrared heater 9 which heats the filmlike board 10 when the photoelectric conversion unit is formed by plasma CVD, a radiant heat thermometer 11 which measures the temperature of the heated board 10, and a temperature controller 13 which controls the temperature of the board 10 to a target temperature based on a temperature measurement on the board 10 by the radiant heat thermometer 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is used for manufacturing a thin-film solar cell that generates power using sunlight by installing it on the roof of a house, the roof of a building, etc. The present invention relates to a substrate heating apparatus that heats the temperature of a substrate with infrared rays when forming a conversion unit.

Solar cells that generate electricity using sunlight by laying outdoors on the roof of a house, the rooftop of a building, etc. are notable because their resources (sunlight) are infinite and non-polluting. Collecting. A typical example of a solar cell (photoelectric conversion device) in which a plurality of photoelectric conversion elements formed on the same substrate are connected in series is a thin film solar cell.
Thin-film solar cells are expected to become the mainstream of solar cells in the future because they are thin and lightweight, inexpensive to manufacture, and easy to increase in area. Demand is also expanding for commercial and general residential use.

In thin film solar cells, a plasma CVD (Chemical Vapor Deposition) method is widely used to produce a photoelectric conversion unit that forms the core. This thin film solar cell by the plasma CVD method has features such that less raw materials are required than a bulk crystalline silicon solar cell and that it can be formed on a lightweight and flexible film substrate. As a material used for the thin film solar cell by the plasma CVD method, there is a silicon-based thin film.
This silicon-based thin film is a silane gas diluted with hydrogen, which is decomposed in plasma and deposited on the substrate. By controlling the substrate temperature, the dilution rate of the silane gas, etc., hydrogenated amorphous silicon films and microcrystals A silicon film can be obtained.

When such a silicon-based thin film is formed, an n-type or p-type semiconductor film can be obtained by adding phosphine or diborane gas containing an impurity element to the source gas. The thin film solar cell is obtained by stacking an n-type, i-type not doped with impurities, and a p-type semiconductor.
In order to obtain a high-quality silicon-based thin film, a high substrate temperature is required. A hydrogenated amorphous silicon film requires 300 ° C. or higher, and a microcrystalline silicon thin film requires about 200 ° C.
For this reason, it is essential to heat the substrate. A polyimide film having a softening point of about 300 ° C. is mainly used as a film substrate that can withstand a high substrate temperature.

In Patent Document 1 (Japanese Patent Application Laid-Open No. 9-59775), when a film is formed by sputtering on a flexible substrate surface by a roll-to-roll method, the substrate is heated during the film formation, that is, moved linearly. While heating the substrate to be formed, measure the temperature of the substrate with an infrared thermometer or a sheet-like thermocouple, feed back to the output of the discharge power source, control the temperature of the substrate, or measure the temperature of the substrate Is fed back, and the temperature of the substrate is controlled by passing the substrate between rolls whose temperatures are adjusted.
This prevents the temperature of the substrate from changing over time due to the influence of radiation and forms a uniform textured electrode surface.

JP 9-59775 A

As a feature of the film substrate, a film having a length of 1000 m or more can be wound on a roll, and a film can be formed on the surface while the film is continuously conveyed. At this time, when a thin film is formed by plasma CVD, it is necessary to ensure a high temperature and not to change with time without contacting the film substrate.
As a method for forming electrodes on a continuously transported film substrate by sputtering, Japanese Patent Application Laid-Open No. 9-59775 is provided. In such an invention, the film substrate is heated by a heater in a sputtering chamber. It is heated and the temperature is measured with an infrared thermometer.

However, in the above-described prior art, although the substrate temperature is measured by an infrared thermometer or a sheet-like thermocouple and fed back to the discharge power output, the substrate temperature is controlled, but the specific substrate temperature is controlled. Means are not disclosed.
In addition, in a thermometer that measures radiation from a substance, light other than radiation becomes a disturbance and it becomes impossible to measure an accurate temperature. However, in the above-described prior art, means for excluding light other than radiation is not provided. .

  The present invention has been made in view of such a situation, and the object thereof is to provide a temperature control means for controlling the temperature of the film substrate to a target value based on the temperature measurement value of the substrate, so that the other than radiation. An object of the present invention is to provide a substrate heating device for a thin-film solar cell that allows accurate temperature control by excluding light from heat.

In order to solve the above-described problems of the prior art, the present invention provides a thin film solar cell in which at least an electrode film and one or more photoelectric conversion units are formed on a film substrate by plasma CVD. When the conversion unit is formed by the plasma CVD, an infrared heater that heats the film-like substrate, a radiant thermometer that measures the temperature of the heated substrate, and a substrate temperature measurement by the radiant thermometer Temperature control means for controlling the temperature of the substrate to a target value based on the value.
In the present invention, it is preferable that the radiant thermometer is provided with a cover that prevents the incidence of heat from the heating infrared heater and the incidence of light emitted from the plasma CVD.

Moreover, in this invention, it is preferable to arrange | position the above-mentioned radiation heat thermometer and cover as follows.
(1) The radiant heat thermometer and the cover are installed in a heating chamber in which the infrared heater is installed.
(2) The radiant heat thermometer and the cover are installed in a plasma CVD chamber in which the plasma CVD is installed.
(3) The radiant heat thermometer and the cover are installed in a winding chamber in which the film-like substrate after the plasma CVD process is wound.

Further, the present invention is preferably configured as follows.
(1) The film-like substrate on which the electrode film is formed is heated by infrared rays by the infrared heater while continuously moving, and a photoelectric conversion unit is formed by the plasma CVD.
(2) The electrode film is formed on one surface of the film-like substrate, and the infrared heater for heating is installed on the surface opposite to the electrode film.
(3) The film-like substrate is a polyimide film.
(4) The plasma CVD is composed of capacitively coupled plasma CVD.
(5) A Si-based thin film such as amorphous Si or microcrystalline Si is formed by plasma CVD using Si and a Si compound gas such as silane as raw materials.
(6) In such a configuration, an impurity gas is added to the source gas in order to obtain n-type and p-type semiconductors.

  As described above, in the present invention, on the film substrate, at least the electrode film and one or more photoelectric conversion units are formed by plasma CVD, and the photoelectric conversion unit is formed by the plasma CVD. An infrared heater for heating the film-shaped substrate, a radiant heat thermometer for measuring the temperature of the heated substrate, and the substrate temperature is controlled to a target value based on the measured temperature value of the substrate by the radiant heat thermometer. Temperature control means, the film-like substrate is heated with an infrared heater, the temperature of the substrate is measured with a radiant thermometer and input to the temperature control means, and the infrared heater is controlled by the temperature control means. The temperature of the substrate is set in advance by configuring a control loop to operate and control the temperature of the substrate so that the temperature of the substrate becomes the target temperature. And can be controlled at all times to the target temperature, the temperature control of the substrate can be performed accurately.

  Further, in the present invention, the radiant heat thermometer is provided with a cover for preventing the incidence of heat from the heating infrared heater and for preventing the incidence of light emission from the plasma CVD. Since the cover is arranged on the meter, the cover can block the incidence of heat from the infrared heater for heating, and can block the incidence of light emission from the plasma CVD, thereby reliably excluding light other than radiation (disturbance). And accurate temperature can be measured.

Furthermore, in the present invention, an electrode film is formed on one surface of the film-like substrate, and the infrared heater for heating is disposed on the surface opposite to the electrode film, so that it is reflected on one surface of the film-like substrate. An electrode film such as Ag having a high rate is formed. As a result, it is difficult for light to pass through, which is an obstacle to radiation. However, heating with an infrared heater is performed from the side where the film surface on which no electrode film is formed is exposed, thereby facilitating light transmission and radiation. Can be an obstacle.
In addition, since the temperature is measured with a radiant thermometer from the side where the film surface is exposed, the measurement accuracy with the radiant thermometer also increases.

  Hereinafter, the substrate heating apparatus for a thin-film solar cell of the present invention will be described in detail based on the embodiments with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic view of a capacitively coupled parallel plate plasma CVD apparatus showing a first embodiment of the present invention.
As shown in FIG. 1, the plasma CVD apparatus according to the present embodiment houses a feed chamber 1 that houses a feed roll 5 that winds up a film 10 with an Ag electrode film, and a take-up roll 6 that winds up the film 10. A winding chamber 4, a heating chamber 2 for heating the film 10 with an infrared heater 9, and a vacuum plasma CVD chamber 3 for forming a silicon thin film on an Ag electrode film formed on the film 10. The infrared heater 9 is disposed to face the film 10 while being spaced from the film 10 conveyed into the heating chamber 2.
The film 10 is continuously conveyed from the feed roll 5 to the take-up roll 6 through the guide roll 5a and the guide roll 6a.

The Ag electrode of the film 10 is formed on the side opposite to the heating side of the infrared heater 9, whereby the film 10 with the Ag electrode can be heated without contact with the infrared heater 9.
The temperature of the film 10 heated by the infrared heater 9 is measured by a radiant heat thermometer 11 installed downstream of the infrared heater 9. A cover 12 for blocking external light is installed around the radiant heat thermometer 11 and on the opposite side of the film 10 so that light from outside that interferes with temperature measurement can be prevented by the cover 12. Shielded.

The temperature measurement value of the radiant heat thermometer 11 is input to a temperature controller (temperature control means) 13, and the temperature controller 13 is connected to the infrared heater 9 and the radiant heat thermometer 11. Each is electrically connected. In the temperature controller 13, a target temperature of the film 10 is set, and the amount of heat of the infrared heater 9 is adjusted so that the temperature measurement value becomes the target temperature, so that the temperature of the film 10 is constantly adjusted. Control is performed to set the target temperature.
That is, the temperature controller 13 feeds back to the infrared heater 9 so that the temperature of the film 10 becomes the target temperature, adjusts the amount of heat of the infrared heater 9, and controls the temperature of the film 10 to the target temperature. By doing so, since the temperature of the film 10 is always controlled to the preset target temperature, the temperature management of the film 10 can be performed accurately. Moreover, since the temperature is measured with the radiant thermometer 11 from the side where the film surface is exposed, the measurement accuracy with the radiant thermometer 11 also increases.

  On the other hand, a cathode 10 and an anode 8 are disposed in the plasma CVD chamber 3 with a film 10 to be conveyed in between, and the flow rate of the source gas is controlled by a mass flow controller (not shown). The pressure in the vacuum chamber of the plasma CVD chamber 3 is adjusted and supplied as a shower from the surface of the cathode electrode 7, and an arbitrary pressure controller (not shown) provided between the vacuum pump and the vacuum chamber is used. It is configured to be set to pressure. The cathode electrode 7 is connected to a high frequency power source via a capacitor (not shown), and generates plasma between the cathode electrode 7 and the anode electrode 8.

The substrate of the film 10 used was a polyimide film having a thickness of 50 μm formed with an Ag electrode formed by sputtering to a thickness of 200 nm. The width of the film 10 was 300 mm, a tension of about 50 N was applied, and the film 10 was conveyed at a winding speed of 1 mm / s. The infrared heater 9 for heating is 500 w.
The temperature of the film 10 measured by the radiant heat thermometer 11 is input to the temperature controller 13, and the temperature controller 13 turns the input voltage of the infrared heater 9 on and off so that the temperature of the film 10 is 200 ° C. It was adjusted.
At this time, the cover 12 for blocking external light is made of Al with alumite surface treatment, the thickness of the peripheral portion of the radiant thermometer 11 is 15 mm, and the distance between the opposite side of the film 10 is 5 mm. It was.
The cathode electrode 7 and the anode electrode 8 were made of stainless steel and were 300 mm square, and the distance between the electrodes was 30 mm. The film 10 was disposed so as to pass a position 5 mm from the anode electrode 8. As source gases, silane and hydrogen gas were introduced at 35 sccm and 2000 sccm, and the pressure was controlled to 4 torr. The high frequency power source supplied power of 300 W to the electrode at 27 MHz, and generated plasma.

The Si film formed under the above conditions has a thickness of 320 nm, and the ratio of the crystal Si peak height at a wavelength of 520 cm −1 to the amorphous Si peak height at a wave number of 480 cm −1 (lc / la) as measured by Raman spectroscopy. Was found to be a microcrystalline Si film of 3.
When the external light shielding cover 12 was not attached, the measurement data of the radiant heat thermometer 11 was out of the measurement area. That is, it can be seen that the measurement data is out of the measurement range due to the influence of the external light, and it is essential to attach the cover 12 for blocking the external light.
On the other hand, when the surface of the film 10 was reversed and the Ag electrode was set on the infrared heater 9 side, the temperature increased only to 120 ° C. This is presumably because the Ag electrode has a high reflectance and the film 10 did not absorb infrared rays.

A photoelectric conversion unit was formed by laminating an n layer, an i layer, and a p layer under the film forming conditions shown in the following (1), (2), and (3) under the same film heating conditions as in Example 1 above. . After each layer was formed, it was rewound to form the next layer. The film formation conditions of the n layer, i layer, and p layer at that time are as follows:
(1) n-layer: Silane, hydrogen gas, and phosphine were introduced as source gases at 5 sccm, 500 sccm, and 0.05 sccm, and the pressure was controlled to be 1 torr. The high-frequency heat source was 27 MHz, and 40 w of power was supplied to the electrodes to generate plasma.
(2) i layer: Five layers were laminated under the same conditions as in Example 1 (required five times to obtain the required thickness of the i layer).
(3) p layer: The substrate temperature was set to 150 ° C., and silane, hydrogen gas, and diborane were introduced as source gases at 5 sccm, 400 sccm, and 0.05 sccm, and the pressure was controlled to be 1 torr. The high-frequency heat source was 27 MHz, and 40 w of power was supplied to the electrodes to generate plasma.

Thus, ITO was formed in the photoelectric conversion unit by sputtering to a thickness of 70 nm, and a Ti / Ag film was further formed as a current collecting electrode, thereby producing a 1 cm ² cell. The photoelectric conversion efficiency was about 4%, but it was confirmed that it was operating as a solar cell.

[Second Embodiment]
FIG. 2 is a schematic view of a capacitively coupled parallel plate plasma CVD apparatus showing a second embodiment of the present invention.
In the second embodiment, the radiant heat thermometer 11 has a cover 12 for shielding external light on the periphery and on the opposite side of the film 10 so as to surround the radiant thermometer 11 as in the first embodiment. Is installed, and the radiation heat thermometer 11 with the cover 12 is installed in the plasma CVD chamber 3 in which plasma CVD is installed.
The temperature measurement value of the plasma CVD chamber 3 detected by the radiant heat thermometer 11 is configured to be input to the temperature controller 13.
Other configurations are the same as those of the first embodiment, and the same members are denoted by the same reference numerals.

[Third Embodiment]
FIG. 3 is a schematic view of a capacitively coupled parallel plate plasma CVD apparatus showing a third embodiment of the present invention.
In the third embodiment, the radiant heat thermometer 11 has a cover 12 for shielding external light on the periphery and the opposite side of the film 10 so as to surround the radiant thermometer 11, as in the first embodiment. Is installed to shield light from the outside that interferes with temperature measurement, and the radiant heat thermometer 11 with the cover 12 is wound around the winding chamber 4 in which the film 10 after the plasma CVD process is wound. It is installed in.
The temperature measurement value of the winding chamber 4 detected by the radiant heat thermometer 11 is configured to be input to the temperature controller 13.
Other configurations are the same as those of the first embodiment, and the same members are denoted by the same reference numerals.

  In both the second embodiment and the third embodiment, the temperatures of the plasma CVD chamber 3 and the winding chamber 4 detected by the radiant heat thermometer 11 are set in the temperature controller 13 in the same manner as in the first embodiment. The input voltage of the heater 9 is controlled to control the temperature of the film 10 to the same temperature.

  While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various changes and modifications can be made based on the technical idea of the present invention.

1 is a schematic view of a capacitively coupled parallel plate plasma CVD apparatus showing a first embodiment of the present invention. It is the schematic of the capacitive coupling type parallel plate plasma CVD apparatus which shows 2nd Embodiment of this invention. It is the schematic of the capacitive coupling type parallel plate plasma CVD apparatus which shows 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Feeding chamber 2 Heating chamber 3 Plasma CVD chamber 4 Winding chamber 5 Feeding roll 6 Winding roll 7 Cathode electrode 8 Anode electrode 9 Infrared heater 10 Ag electrode film (substrate)
11 Radiation thermometer 12 Cover for blocking external light 13 Temperature controller (temperature control means)

Claims (11)

  In a thin film solar cell in which at least an electrode film and one or a plurality of photoelectric conversion units are formed on a film-like substrate by plasma CVD, when the photoelectric conversion unit is formed by plasma CVD, the film-like substrate Infrared heater for heating the substrate, a radiant heat thermometer for measuring the temperature of the heated substrate, and a temperature control means for controlling the temperature of the substrate to a target value based on the measured temperature value of the substrate by the radiant heat thermometer And a substrate heating apparatus for a thin film solar cell.   2. The thin film according to claim 1, wherein the radiant thermometer is provided with a cover for preventing the incidence of heat from the heating infrared heater and preventing the incidence of light emission from the plasma CVD. Solar cell substrate heating device.   The substrate heating apparatus for a thin-film solar cell according to claim 2, wherein the radiant thermometer and the cover are installed in a heating chamber in which the infrared heater is installed.   The substrate heating apparatus for a thin-film solar cell according to claim 2, wherein the radiant thermometer and the cover are installed in a plasma CVD chamber in which the plasma CVD is installed.   3. The substrate heating apparatus for a thin film solar cell according to claim 2, wherein the radiant thermometer and the cover are installed in a winding chamber in which the film-like substrate after the plasma CVD process is wound.   The film-like substrate on which the electrode film is formed is heated by infrared rays by the infrared heater while continuously moving, and a photoelectric conversion unit is formed by the plasma CVD. The board | substrate heating apparatus of the thin film solar cell of description.   2. The thin film solar cell according to claim 1, wherein the electrode film is formed on one surface of the film-like substrate, and the infrared heater for heating is disposed on a surface opposite to the electrode film. Substrate heating device.   The said film-form board | substrate is a polyimide, The board | substrate heating apparatus of the thin film solar cell of Claim 1 characterized by the above-mentioned.   The said plasma CVD is comprised from capacitive coupling type plasma CVD, The board | substrate heating apparatus of the thin film solar cell of Claim 1 characterized by the above-mentioned.   2. The substrate heating of a thin-film solar cell according to claim 1, wherein a Si-based thin film such as amorphous Si or microcrystalline Si is formed by plasma CVD using Si compound gas such as hydrogen and silane as a raw material. apparatus.   The substrate heating apparatus for a thin film solar cell according to claim 10, wherein an impurity gas is added to the source gas in order to obtain an n-type and a p-type semiconductor.

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