KR20120004174A - Back contact type solar cell and method of fabricating the same - Google Patents

Back contact type solar cell and method of fabricating the same Download PDF

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Publication number
KR20120004174A
KR20120004174A KR1020100064898A KR20100064898A KR20120004174A KR 20120004174 A KR20120004174 A KR 20120004174A KR 1020100064898 A KR1020100064898 A KR 1020100064898A KR 20100064898 A KR20100064898 A KR 20100064898A KR 20120004174 A KR20120004174 A KR 20120004174A
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South Korea
Prior art keywords
impurity
impurity diffusion
region
silicon substrate
solar cell
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KR1020100064898A
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Korean (ko)
Inventor
서준모
송석현
양수미
이경원
이진섭
Original Assignee
현대중공업 주식회사
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Priority to KR1020100064898A priority Critical patent/KR20120004174A/en
Publication of KR20120004174A publication Critical patent/KR20120004174A/en

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    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L31/00Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/06Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier
    • H01L31/068Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells
    • H01L31/0682Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells back-junction, i.e. rearside emitter, solar cells, e.g. interdigitated base-emitter regions back-junction cells
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L31/00Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18Processes or apparatus peculiar to the manufacture or treatment of these devices or of parts thereof
    • H01L31/1804Processes or apparatus peculiar to the manufacture or treatment of these devices or of parts thereof comprising only elements of Group IV of the Periodic System
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L31/00Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02Details
    • H01L31/0224Electrodes
    • H01L31/022408Electrodes for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/022425Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • H01L31/022441Electrode arrangements specially adapted for back-contact solar cells
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/50Photovoltaic [PV] energy

Abstract

The present invention relates to a back-electrode solar cell and a method of manufacturing the same, which can maximize the photoelectric conversion efficiency of the solar cell by removing the pn overlap region in advance of the diffusion process in the manufacturing method of the back-electrode solar cell, according to the present invention The back electrode solar cell includes a silicon substrate, a plurality of first impurity diffusion regions and second impurity diffusion regions alternately formed on a back surface of the silicon substrate, and disposed between the first impurity diffusion region and the second impurity diffusion region. Trenchs having a predetermined depth, and a back electrode connected to the first impurity diffusion region and the second impurity diffusion region and composed of an anode and a cathode.

Description

Back contact type solar cell and its manufacturing method {Back contact type solar cell and method of fabricating the same}

The present invention relates to a back electrode solar cell and a method of manufacturing the same, and more particularly, to remove the pn overlap region before the diffusion process of the back electrode solar cell manufacturing method to maximize the photoelectric conversion efficiency of the solar cell. The present invention relates to a back electrode solar cell and a method of manufacturing the same.

A solar cell is a key element of photovoltaic power generation that converts sunlight directly into electricity, and is basically a diode composed of a p-n junction. In the process of converting sunlight into electricity by solar cells, when solar light is incident on the pn junction of solar cells, electron-hole pairs are generated, and electrons move to n layers and holes move to p layers by the electric field. Photovoltaic power is generated between the pn junctions, and when a load or a system is connected to both ends of the solar cell, current flows to generate power.

Meanwhile, referring to the structure of a general solar cell, the front and rear electrodes are respectively provided on the front and rear surfaces. As the front electrode is provided on the front surface, the light receiving area is reduced by the area of the front electrode. As such, a back-electrode solar cell has been proposed to solve the problem of the light receiving area being reduced. The back electrode solar cell is characterized by maximizing the light receiving area of the solar cell by providing a (+) electrode and a (-) electrode on the back of the solar cell.

1 is a cross-sectional view of a back electrode solar cell of US Pat. No. 7,339,110. Referring to FIG. 1, a p + region, which is a region where p-type impurity ions have been implanted, and an n + region, which is a region where n-type impurity ions have been implanted, are provided in a rear surface of a silicon substrate, and interdigitated with each other on the p + region and the n + region. A metal electrode 50, 52 of the structure is provided.

At this time, one of optimization conditions for forming a p + region and an n + region is that the p + region and the n + region should not overlap each other. Since the recombination of holes and electrons rapidly increases in the overlapping area, the efficiency of the back-electrode solar cell decreases as the overlapping area is larger or larger.

The present invention provides a back-electrode solar cell having high efficiency by removing the overlapping region between the p-type impurity diffusion region and the n-type impurity diffusion region which affect the photoelectric conversion efficiency in the back-electrode solar cell as a high efficiency solar cell and its manufacture It is to provide a method.

In order to achieve the above object, a back electrode solar cell according to the present invention includes a silicon substrate, a plurality of first impurity diffusion regions and second impurity diffusion regions alternately formed on a rear surface of the silicon substrate, and the first impurity diffusion. Trenches having a predetermined depth provided between the region and the second impurity diffusion region, and a back electrode connected to the first impurity diffusion region and the second impurity diffusion region and composed of an anode and a cathode.

The depth of the trench may be characterized in that 0.3 to 10 micrometers (μm).

The trenches may be narrower than the width of the first impurity diffusion region or the second impurity diffusion region.

The first impurity diffusion region and the second impurity diffusion region may be regions formed of different types of impurities selected from p-type semiconductor impurities and n-type semiconductor impurities, respectively.

A method of manufacturing a back-electrode solar cell according to the present invention includes preparing a crystalline silicon substrate of a first conductivity type, and a predetermined region in the remaining region except for a region in which a first impurity and a second impurity are diffused on a back surface of the silicon substrate. Forming trenches having a depth, applying a liquid first impurity and a second impurity diffusion paste onto a region where the first impurity and the second impurity are to be diffused, and performing a thermal diffusion process to form the first impurity and Diffusing a second impurity diffusion paste into the silicon substrate, and forming a back electrode connected to a region in which the first impurity and the second impurity are diffused.

Forming trenches having a predetermined depth in regions other than regions where the first and second impurities are to be diffused on the back surface of the silicon substrate may be performed by etching or laser scribing. It can be characterized.

The coating of the first impurity and the second impurity diffusion paste may include depositing a first screen mask on the back surface of the silicon substrate to expose the substrate of the portion to which the first impurity is to be applied, and applying the first impurity diffusion paste. Applying on the entire surface of the silicon substrate including the first screen mask, removing the first screen mask, and seating a second screen mask that exposes the substrate to a portion to which the second impurity is to be applied; And applying the impurity diffusion paste on the entire surface of the silicon substrate including the second screen mask, and removing the second screen mask.

The first and second impurities may be different types of impurities selected from p-type semiconductor impurities and n-type semiconductor impurities, respectively.

The back-electrode heterojunction solar cell and its manufacturing method according to the present invention have the following effects.

By removing the overlapping region between the p-type impurity diffusion region and the n-type impurity diffusion region formed on the back surface of the silicon substrate, the recombination of the charge carriers can be prevented, thereby improving the photoelectric conversion efficiency of the solar cell.

1 is a cross-sectional view showing the structure of a back electrode solar cell according to the prior art.
2 is a cross-sectional view showing the structure of a back electrode solar cell according to an embodiment of the present invention.
3 is a flowchart illustrating a method of manufacturing a back electrode solar cell according to an embodiment of the present invention.
4A to 4G are cross-sectional views illustrating a method of manufacturing a back electrode solar cell according to an exemplary embodiment of the present invention.

Hereinafter, a back electrode heterojunction solar cell and a method of manufacturing the same according to an embodiment of the present invention will be described with reference to the drawings. 2 is a cross-sectional view showing the structure of a back electrode solar cell according to an embodiment of the present invention.

Referring to FIG. 2, a back electrode solar cell includes a silicon substrate 200, a plurality of first impurity diffusion regions 240 and a second impurity diffusion region 250, trenches 210, and a back electrode 260. Include. The plurality of first impurity diffusion regions 240 and the second impurity diffusion regions 250 are alternately formed on the rear surface of the silicon substrate 200. The trenches 210 are provided at a predetermined depth between the first impurity diffusion region 240 and the second impurity diffusion region 250. The back electrode 260 is connected to the first impurity diffusion region 240 and the second impurity diffusion region 250 and includes an anode and a cathode.

Here, the first impurity diffusion region 240 may be a p-type semiconductor impurity region, and the second impurity diffusion region 250 may be an n-type semiconductor impurity region. In this case, the p-type semiconductor impurity is, for example, a Group 3 element such as boron (B), aluminum (Al), gallium (Ga), indium (In), and the like. Group 5 elements such as (P) and arsenic (As).

Since each of the semiconductor impurity regions 240 and 250 is formed to be separated from each other by the trenches 210 so as not to overlap with each other, the possibility of recombination of electrons and holes due to overlap may be reduced, thereby maximizing the efficiency of the solar cell.

The depths of the trenches 210 may be formed in units of several micrometers (μm), similarly to the depths of the first impurity diffusion region 240 and the second impurity diffusion region 250. In particular, the depth of the trenches 210 in the present invention may be 0.3 to 10 micrometers (μm). The width of the trenches 210 may be smaller than the width of the first impurity diffusion region 240 or the second impurity diffusion region 250.

Unlike the above description, the first impurity diffusion region 240 may be an n-type semiconductor impurity region, and the second impurity diffusion region 250 may be a p-type semiconductor impurity region.

3 is a flowchart illustrating a method of manufacturing a back electrode solar cell according to an embodiment of the present invention, and FIGS. 4A to 4G illustrate a method of manufacturing a back electrode solar cell according to an embodiment of the present invention. It is process sectional view for.

Referring to FIG. 3, a method of manufacturing a back-electrode solar cell according to the present invention includes preparing a first conductive crystalline silicon substrate 200 (S301), a texturing process (S302), and the silicon substrate ( Forming trenches having a predetermined depth in the remaining region except for the region where the first impurity 242 and the second impurity 252 are to be diffused on the rear surface of the step 200 (S303), and the first impurity 242 and the second impurity. Applying the liquid first impurity 242 and the second impurity 252 diffusion paste to a region where the impurity 252 is to be diffused (S304), and performing a thermal diffusion process to perform the first impurity 242 or the second Diffusing an impurity 252 diffusion paste into the silicon substrate 200 (S305), and forming a back electrode 260 connected to regions 240 and 250 where the first and second impurities are diffused. Step S306 may be included.

3 and 4A, a first conductive type, for example, n-type crystalline silicon substrate 200 is prepared (S301). Then, a texturing process is performed to form irregularities on the surface of the silicon substrate 200 (S302). The texturing process is for maximizing light absorption, and may be performed using a dry etching method such as wet etching or reactive ion etching. Next, trenches 210 having a predetermined depth are formed on the back surface of the silicon substrate 200 except for regions where the first impurity 242 or the second impurity 252 is to be diffused (S303). The trench 210 may be formed by an etching method or a laser scribing method. The etching method may use, for example, one of wet etching, dry etching, electric etching, and mechanical etching. The laser scribing method is a method of scraping the surface of the silicon substrate 200 using a laser to make a groove.

Next, as shown in FIGS. 4C through 4E, the liquid first impurity 242 and the second impurity 252 are applied to a region where the first impurity 242 and the second impurity 252 are to be diffused ( S304). Referring to FIG. 4C, a first screen mask 220 exposing the substrate 200 at a portion where the first impurity 242 is to be applied is mounted on the back surface of the silicon substrate 200. The first impurity 242 diffusion paste is coated on the entire surface of the silicon substrate 200 including the first screen mask 220. In this case, the first impurity 242 may be a p-type impurity, and the liquid p-type impurity diffusion paste may be applied using a roller or the like.

Referring to FIG. 4D, after removing the first screen mask 220, the second screen mask 230 exposing the substrate 200 is placed on a portion where the second impurity 252 is to be applied. The second impurity 252 diffusion paste is coated on the entire surface of the silicon substrate 200 including the second screen mask 230. In this case, the second impurity 252 may be an n-type impurity, and the liquid n-type impurity diffusion paste may be applied using a roller or the like. Next, the second screen mask 230 is removed. In this way, as shown in FIG. 4E, the first impurity 242 and the second impurity 252 diffusion paste are alternately applied to the rear surface of the silicon substrate 200 at regular intervals.

Referring to FIG. 4F, a thermal diffusion process is performed on the silicon substrate 200 to which the first impurity 242 and the second impurity 252 are applied to transfer the impurities 242 and 252 into the silicon substrate 200. Diffusion (S305). Accordingly, the first impurity diffusion region 240 and the second impurity diffusion region 250 are formed, and the impurity diffusion regions 240 and 250 have no regions where the impurities 242 and 252 overlap each other. The trenches 210 may be spaced apart from each other with the trenches 210 interposed therebetween.

Thereafter, as shown in FIG. 4G, the back electrode 260 is formed to be connected to the formed first impurity diffusion region 240 and the second impurity diffusion region 250 (S306). The back electrode 260 may be formed by overlapping and printing a material such as silver (Ag) or aluminum (Al) on the impurity diffusion regions 240 and 250. Therefore, when the electrode terminals of the positive and negative electrodes are removed from the same surface of the back surface of the silicon substrate 200 and the load or the system are connected, the electric current flows to generate power.

As described above, in the back-electrode solar cell according to the present invention, the trenches 210 are formed in the remaining regions other than the region where the impurities 242 and 252 are to be diffused before the diffusion process, thereby forming the gap between the diffusion regions 240 and 250. It is possible to provide a high efficiency back-electrode solar cell by preventing the overlap region formation.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

200: crystalline silicon substrate 210: trench
220: first screen mask 230: second screen mask
240: first impurity diffusion region 242 first impurity (diffusion paste)
250: second impurity diffusion region 252: second impurity (diffusion paste)
260 back electrode

Claims (8)

  1. Silicon substrates;
    A plurality of first impurity diffusion regions and second impurity diffusion regions formed alternately on a rear surface of the silicon substrate;
    Trenches having a predetermined depth provided between the first impurity diffusion region and the second impurity diffusion region; And
    And a back electrode connected to the first impurity diffusion region and the second impurity diffusion region, the back electrode comprising an anode and a cathode.
  2. The method of claim 1,
    The depth of the trench is a back electrode solar cell, characterized in that 0.3 to 10 micrometers (㎛).
  3. The method of claim 1,
    The width of the trench is a back-electrode solar cell, characterized in that narrower than the width of the first impurity diffusion region or the second impurity diffusion region.
  4. The method of claim 1,
    And the first impurity diffusion region and the second impurity diffusion region are regions composed of different types of impurities selected from p-type semiconductor impurities and n-type semiconductor impurities, respectively.
  5. Preparing a crystalline silicon substrate of a first conductivity type;
    Forming trenches of a predetermined depth on a rear surface of the silicon substrate except for regions where the first and second impurities are to be diffused;
    Applying a liquid first impurity and a second impurity diffusion paste on a region where the first impurity and the second impurity are to be diffused;
    Performing a thermal diffusion process to diffuse the first impurity and the second impurity diffusion paste into the silicon substrate; And
    And forming a back electrode connected to the region in which the first impurity and the second impurity are diffused.
  6. The method of claim 5,
    Forming trenches having a predetermined depth in the remaining regions of the silicon substrate except for the region where the first and second impurities are to be diffused
    A method of manufacturing a back-electrode type solar cell, which is performed by an etching method or a laser scribing method.
  7. The method of claim 5,
    The step of applying the first impurity and the second impurity diffusion paste
    Mounting a first screen mask on the back surface of the silicon substrate to expose a substrate of a portion to which the first impurity is to be applied, and applying a first impurity diffusion paste on the entire surface of the silicon substrate including the first screen mask;
    The first screen mask is removed, a second screen mask for exposing the substrate is exposed to a portion to which the second impurity is to be applied, and the second impurity diffusion paste is applied onto the entire silicon substrate including the second screen mask. Doing; And
    And removing the second screen mask.
  8. The method of claim 5,
    The first impurity and the second impurity are back electrode type solar cells, characterized in that different types of impurities each selected from p-type semiconductor impurities and n-type semiconductor impurities.
KR1020100064898A 2010-07-06 2010-07-06 Back contact type solar cell and method of fabricating the same KR20120004174A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102832270A (en) * 2012-08-16 2012-12-19 友达光电股份有限公司 Solar battery and manufacturing method thereof
CN103943711A (en) * 2014-04-30 2014-07-23 山东力诺太阳能电力股份有限公司 Back contact-type solar cell structure based on N-type silicon substrate and manufacturing method
WO2017106213A1 (en) * 2015-12-16 2017-06-22 Sunpower Corporation Solar cell fabrication using laser patterning of ion-implanted etch-resistant layers and the resulting solar cells

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102832270A (en) * 2012-08-16 2012-12-19 友达光电股份有限公司 Solar battery and manufacturing method thereof
WO2014026400A1 (en) * 2012-08-16 2014-02-20 友达光电股份有限公司 Solar cell and manufacturing method thereof
CN103943711A (en) * 2014-04-30 2014-07-23 山东力诺太阳能电力股份有限公司 Back contact-type solar cell structure based on N-type silicon substrate and manufacturing method
WO2017106213A1 (en) * 2015-12-16 2017-06-22 Sunpower Corporation Solar cell fabrication using laser patterning of ion-implanted etch-resistant layers and the resulting solar cells
US10079319B2 (en) 2015-12-16 2018-09-18 Sunpower Corporation Solar cell fabrication using laser patterning of ion-implanted etch-resistant layers and the resulting solar cells

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