JP2008235947A - MANUFACTURING METHOD OF muc-Si OR POLYCRYSTALLINE Si PHOTOVOLTAIC CELL, AND PHOTOVOLTAIC CELL - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an Si photovoltaic cell having an Si power generating film with low defect rate and high quality, and with high photovoltaic conversion efficiency. <P>SOLUTION: The manufacturing method of an μc-Si (microcrystalline silicon) or polycrystalline Si photovoltaic cell comprises a step of laminating a first transparent conductive film, and a p/i/n-type or an n/i/p-type μc-Si or polycrystalline Si power generating film on the substrate; soaking a support substrate into a cyan solution, containing a crown ether, and bringing CN ions into the μc-Si or polycrystalline Si power generating film; cleaning the support substrate; and sequentially forming a second transparent conductive film and a backside electrode on the μc-Si or polycrystalline Si power generating film. The thickness of the μc-Si or polycrystalline Si power generating film is 1 μm or larger, and the CN ions are brought into the μc-Si or polycrystalline Si power generating film, while soaking the support substrate in the crown ether. At the same time, a voltage is applied to the μc-Si or polycrystalline Si power generating film that promotes pulling in of the CN ions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a Si solar cell and a solar cell.

  Conventionally, as a μc-Si solar cell, for example, the one shown in FIG. 4 is known.

Number 1 in the figure indicates a glass substrate having a thickness of about 1 mm, for example. On this substrate 1, a first transparent conductive film 2 having a film thickness of 0.6 to 1.0 μm made of ITO, SnO ₂ or the like, a μc-Si power generation film 3, a film thickness of 10 to 200 nm made of ITO, ZnO or the like. The second transparent conductive film 4 and the back electrode 5 are sequentially formed. Here, the μc-Si power generation film 3 includes a p-type μc-Si power generation film 3a, an i-type μc-Si power generation film 3b, and an n-type μc-Si power generation film 3c. The film thickness of the μc-Si power generation film is 1 μm or more in total. A current collecting electrode 6 is formed on a part of the first transparent conductive film 2 on the substrate 1.

  In the solar cell having such a configuration, sunlight enters from the glass substrate 1 side, passes through the transparent electrode film 2, and enters the μc-Si power generation film 3. The sunlight is absorbed by the power generation film 3b, and an electromotive force is generated between the transparent conductive film 2 and the back electrode 5, and the power can be taken out to the outside.

By the way, in the solar cell, the i-type μc-Si power generation film 3b, which is one component of the μc-Si power generation film 3, is generally formed using plasma CVD. When high-speed film formation is performed by increasing the input power, defects such as Si dumbbelling bonds increase as compared to low-speed film formation. Therefore, a high-quality μc-Si power generation film with low defects cannot be obtained in high-speed film formation. As a thin film Si solar cell using a CN group for a film thickness of several hundred nm, there is Patent Document 1 (Japanese Patent Laid-Open No. 2001-189484).
JP 2001-189484 A (see paragraphs [0044] to [0048] and FIG. 1)

  The present invention has been made in view of the above circumstances, and after forming a p / i / n-type or n / i / p-type μc-Si or polycrystalline Si power generation film, the μc-Si or polycrystalline Si is formed. By performing cyan treatment on the power generation film, it is possible to form a high-quality μc-Si or polycrystalline Si power generation film with low defects, thereby obtaining a highly efficient μc-Si or polycrystalline Si solar cell. It aims at providing the manufacturing method of a crystalline Si solar cell.

  Another object of the present invention is to provide a μc-Si or polycrystalline Si solar cell with high photoelectric conversion efficiency by the above production method.

  The first invention of the present application includes a step of laminating a first transparent conductive film, p / i / n-type or n / i / p-type μc-Si or polycrystalline Si power generation film on a support substrate, and the support substrate Is immersed in a cyan solution containing crown ether, CN ions are drawn into the μc-Si or polycrystalline Si power generation film, the support substrate is washed, and the μc-Si or polycrystalline Si power generation film is formed. A step of sequentially forming a second transparent conductive film and a back electrode, wherein the μc-Si or polycrystalline Si power generation film has a thickness of 1 μm or more, and the support substrate is in a cyan solution containing crown ether. The CN ions are drawn into the μc-Si or polycrystalline Si power generation film while being immersed in the film, and a voltage is applied to the μc-Si or polycrystalline Si power generation film to promote the pulling of the CN ions. Μc− It is a manufacturing method of Si or a polycrystal Si solar cell.

  The second invention of the present application includes a step of laminating a first transparent conductive film, p / i / n-type or n / i / p-type μc-Si or polycrystalline Si power generation film on a support substrate, and the support substrate Is immersed in the HCN solution, CN ions are drawn into the μc-Si or polycrystalline Si power generation film, a step of cleaning the support substrate, and a second step on the μc-Si or polycrystalline Si power generation film. A step of sequentially forming a transparent conductive film and a back electrode, wherein the μc-Si or polycrystalline Si power generation film has a film thickness of 1 μm or more, and the support substrate is immersed in an HCN solution so that the μc-Si or The CN ions are attracted into the polycrystalline Si power generation film and a voltage is applied to the μc-Si or polycrystalline Si power generation film to promote the attraction of the CN ions. It is a manufacturing method of a solar cell.

  A third invention of the present application is a μc-Si or polycrystalline Si solar cell obtained by the manufacturing method of claim 1 or 2.

  According to the present invention, by forming a p / i / n-type or n / i / p-type μc-Si or polycrystalline Si power generation film, the μc-Si or polycrystalline Si power generation film is subjected to cyan treatment. In this case, a strong hand called Si-CN is made in the i-type μc-Si or polycrystalline Si power generation layer in the μc-Si or polycrystalline Si power generation film, so that high-quality μc-Si or polycrystalline Si with low defects is produced. A μc-Si or polycrystalline Si solar cell having a power generation film and high photoelectric conversion efficiency can be obtained.

  In addition, the present invention can provide a μc-Si or polycrystalline Si solar cell having high photoelectric conversion efficiency by the above production method.

  Hereinafter, the Si solar cell of the present invention will be described in more detail.

  FIG. 1 shows a film forming apparatus for a power generation film, which is one configuration of the solar cell of the present invention. Reference numeral 11 in the figure indicates a vacuum vessel having a gas discharge port 12. On the upper side and the lower side of the space 13 of the vacuum vessel 11, a heater 15 and an electrode 16 are disposed so as to face each other while supporting the substrate 14 on the lower surface. The electrode 16 is supported by a gas mixing box 17 having an open top.

  An impedance matching unit 18 and a high frequency power source 19 are electrically connected to the electrode 16 in sequence. A gas supply board 20 having a large number of through holes (not shown) formed in a lattice shape at the top is disposed at the bottom of the gas mixing box 17. The gas supply board 20 is supplied with a source gas from a source gas supply source 21 through a gas supply pipe 22. A vacuum pump 23 that exhausts the inside of the vacuum vessel 11 is connected to the gas discharge port 12.

  FIG. 2 shows another power generation film forming apparatus which is one configuration of the solar cell of the present invention. However, the same members as those in FIG. Reference numeral 24 in the figure indicates a vacuum vessel (or a pressurized vessel). Reference numeral 25 denotes a processing gas supply source that supplies the processing gas to the gas supply board 20 via the gas supply pipe 22. However, in the vacuum pump 23 of FIG. 2, in the case of a pressurizing process, it is sealed (no vacuum pump is used).

  In the present invention, the cyan treatment after forming the p / i / n type or n / i / p type μc-Si power generation film or the polycrystalline Si power generation film includes the following methods 1) and 2). .

  1) Means for cleaning the support substrate by laminating the Si power generation film, immersing the support substrate in a cyan solution containing crown ether, drawing CN ions into the Si power generation film. However, when the film thickness of the Si power generation film is 1 μm or more, it is necessary to promote the pulling of CN ions by applying a voltage to the Si power generation film when CN ions are drawn into the Si power generation film. This is because the Si power generation film has a film thickness of 1 μm or more, so CN ions do not sufficiently enter the Si power generation film, and a strong hand called Si—CN cannot be made in the Si power generation film. In addition, it is preferable that the liquid temperature of a cyan solution shall be room temperature-100 degreeC, applied voltage: 0-40V, and processing time: 10 second-30 minutes. In the above range, defect suppression by the CN group is effective.

  2) Means for cleaning the support substrate after laminating the Si power generation film, immersing the support substrate in an HCN solution, drawing CN ions into the Si power generation film. However, as in the case of 1) above, since the film thickness of the Si power generation film is 1 μm or more, when CN ions are drawn into the Si power generation film, a voltage is applied to the Si power generation film to promote the pulling of the CN ions. It is necessary to. The reason is the same as in the case of 4) above. The liquid temperature of the HCN solution is preferably room temperature to 100 ° C., applied voltage: 0 to 40 V, and treatment time: 10 seconds to 30 minutes. In the above range, defect suppression by the CN group is effective.

  In the present invention, by performing cyan treatment on the Si power generation film, CN ions are drawn into the μc-Si or polycrystalline Si layer, which is one component of the Si power generation film, and the Si dangling bonds are terminated by CN. Thereby, since a strong hand called Si-CN is made in the i-type Si power generation layer, a high-quality Si power generation film with low defects can be formed. Moreover, according to the Si solar cell having such a Si power generation film, high photoelectric conversion efficiency can be obtained.

  Examples of the present invention will be described below.

Example 1
Reference is made to FIGS. Here, FIG. 3A is a cross-sectional view of a substrate on which a μc-Si power generation film is formed on a glass substrate, and FIG. 3B is an explanatory view of the substrate immersed in a cyan solution containing a crown ether solution. Show.

  1) First, a first transparent conductive film 32, a p-type μc-Si layer 33a, an i-type μc-Si layer 33b, and an n-type μc-Si layer 33c are formed on a glass substrate 31 as a support substrate. A μc-Si power generation film 33 was formed, and a substrate 34 was formed (see FIG. 3A).

  2) Next, as shown in FIG. 3B, the base 34 is placed in a cyan solution 38 accommodated in an electrolytic cell 37 while applying a positive voltage using a variable power source 35 and a Pt electrode 36. Soaked. Note that the amount of crown ether used is equal to or greater than that of KCN, and xylene is used as the solution. This is because silicon etching occurs when pure water is used.

  3) Subsequently, after the cyan treatment, the substrate 34 was taken out of the cyan solution 38 and washed sequentially with acetone and pure water. Thereafter, although not shown, a μc-Si solar cell was manufactured by sequentially forming a second transparent conductive film and a back electrode made of Ag on the μc-Si power generation film 33.

  According to Example 1, after laminating the first transparent conductive film 32 and the p / i / n type μc-Si power generation film 33 on the glass substrate 31, the glass substrate 31 is immersed in the HCN solution, CN ions are attracted into the i-type μc-Si power generation film 33, and a strong hand called Si-CN is made in the i-type μc-Si power generation layer in the Si power generation film. Therefore, a high-quality Si power generation film with low defects can be obtained. Moreover, according to the Si solar cell having such a Si power generation film, high photoelectric conversion efficiency can be obtained.

  In fact, when the μc-Si solar cell according to Example 1 and the conventional μc-Si solar cell not subjected to the cyan treatment were examined for the form factor, the present invention increased the form factor by 6% compared to the conventional case. As a result, it was confirmed that the conversion efficiency was improved by 4%.

(Example 2)
Although not shown in the figure, in Example 2, as compared with Example 1, the substrate in which the μc-Si power generation film is formed on the glass substrate is immersed in the HCN solution instead of the cyan solution containing the crown ether solution. Except for this point, the same process as in Example 1 was performed to form a Si power generation film.

  In fact, when the μc-Si solar cell according to Example 2 and the conventional μc-Si solar cell not subjected to the cyan treatment were examined, the short-circuit current density was reduced by 5%, but the open-circuit voltage was 5% and the shape factor was 3 As a result, it was confirmed that the conversion efficiency was improved by 4.5%.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. Explanatory drawing of the other film forming apparatus of the electric power generation film which is one structure of the solar cell of this invention. Explanatory drawing of the manufacturing method of the (micro | micron | mu) -Si solar cell which concerns on Example 1 of this invention. FIG. 6 is a schematic cross-sectional view of a conventional μc-Si solar cell.

Explanation of symbols

11, 24 ... Vacuum container, 12 ... Gas outlet, 13 ... Vacuum container space,
14, 31 ... Substrate, 15 ... Heater, 16 ... Electrode,
17 ... Gas mixing box, 18 ... Impedance matching device,
19 ... high frequency power supply, 20 ... gas supply panel, 21 ... source gas supply source,
22 ... Gas supply pipe, 23 ... Vacuum pump, 25 ... Process gas supply source,
32... First transparent conductive film, 33... Μc-Si power generation film,
33a ... p-type μc-Si power generation layer, 33b ... i-type μc-Si power generation layer,
33c ... n-type [mu] c-Si power generation layer, 35 ... Variable power supply, 36 ... Pt electrode.

Claims (3)

A step of laminating a first transparent conductive film, p / i / n-type or n / i / p-type μc-Si or polycrystalline Si power generation film on a support substrate; and a cyan solution containing crown ether on the support substrate. A step of drawing CN ions into the μc-Si or polycrystalline Si power generation film, a step of cleaning the support substrate, and a second transparent conductive film on the μc-Si or polycrystalline Si power generation film. And sequentially forming the back electrode,
The μc-Si or polycrystalline Si power generation film has a thickness of 1 μm or more, and the CN ions are introduced into the μc-Si or polycrystalline Si power generation film while the support substrate is immersed in a cyan solution containing crown ether. A method of manufacturing a μc-Si or polycrystalline Si solar cell, wherein the pulling of the CN ions is promoted by applying a voltage to the μc-Si or polycrystalline Si power generation film. Laminating a first transparent conductive film, p / i / n-type or n / i / p-type μc-Si or polycrystalline Si power generation film on a support substrate, immersing the support substrate in an HCN solution, A step of drawing CN ions into the μc-Si or polycrystalline Si power generation film; a step of cleaning the support substrate; and a second transparent conductive film and a back electrode on the μc-Si or polycrystalline Si power generation film. A step of sequentially forming,
The film thickness of the μc-Si or polycrystalline Si power generation film is 1 μm or more, the support substrate is immersed in an HCN solution to draw the CN ions into the μc-Si or polycrystalline Si power generation film, and the μc A method for producing a μc-Si or polycrystalline Si solar cell, wherein a voltage is applied to a Si or polycrystalline Si power generation film to promote the attraction of the CN ions.   A μc-Si or polycrystalline Si solar cell obtained by the manufacturing method according to claim 1.

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