CN116130548A - Contact structure of solar cell, preparation method and solar cell - Google Patents
Contact structure of solar cell, preparation method and solar cell Download PDFInfo
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- CN116130548A CN116130548A CN202211105016.XA CN202211105016A CN116130548A CN 116130548 A CN116130548 A CN 116130548A CN 202211105016 A CN202211105016 A CN 202211105016A CN 116130548 A CN116130548 A CN 116130548A
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- 239000000758 substrate Substances 0.000 claims abstract description 103
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- 229910052710 silicon Inorganic materials 0.000 claims abstract description 102
- 239000010703 silicon Substances 0.000 claims abstract description 102
- 238000002161 passivation Methods 0.000 claims abstract description 82
- 229910052751 metal Inorganic materials 0.000 claims abstract description 59
- 239000002184 metal Substances 0.000 claims abstract description 59
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- 238000000151 deposition Methods 0.000 claims abstract description 30
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- 229910052581 Si3N4 Inorganic materials 0.000 claims description 33
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 33
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 28
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 26
- 230000008021 deposition Effects 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 12
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 9
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 8
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- 238000004140 cleaning Methods 0.000 claims description 5
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- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 claims description 3
- 239000002131 composite material Substances 0.000 abstract description 2
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- 229910052709 silver Inorganic materials 0.000 description 13
- 239000004332 silver Substances 0.000 description 13
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 9
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- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
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- JLTRXTDYQLMHGR-UHFFFAOYSA-N trimethylaluminium Chemical compound C[Al](C)C JLTRXTDYQLMHGR-UHFFFAOYSA-N 0.000 description 2
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially 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 specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
- H01L31/1804—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof comprising only elements of Group IV of the Periodic Table
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- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially 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 specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0216—Coatings
- H01L31/02161—Coatings for devices characterised by at least one potential jump barrier or surface barrier
- H01L31/02167—Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially 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 specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0224—Electrodes
- H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
- H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
- H01L31/022433—Particular geometry of the grid contacts
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- H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
- H01L31/186—Particular post-treatment for the devices, e.g. annealing, impurity gettering, short-circuit elimination, recrystallisation
- H01L31/1868—Passivation
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- Y—GENERAL 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
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Abstract
The invention relates to the technical field of photovoltaic cells, and provides a contact structure of a solar cell, a preparation method and the solar cell, wherein the preparation method of the contact structure of the solar cell comprises the steps of depositing a passivation dielectric film on the surface of a silicon substrate; coating metal slurry on a target area of the passivation dielectric film, wherein the metal slurry contains corrosion components capable of corroding the passivation dielectric film, and a sintering process is adopted to reduce the thickness of the passivation dielectric film on the target area, the metal slurry forms an electrode grid line, and the thickness of the passivation dielectric film on the target area is larger than zero; and applying a guiding charge on the electrode grid line, wherein the guiding charge is set to be different from the charge of unbalanced carriers which can be generated in the silicon substrate, and irradiating the passivation dielectric film of the non-target area by using a light source. By the arrangement, the problem that the composite loss of the metal contact area of the solar cell in the prior art is high is solved.
Description
Technical Field
The invention relates to the technical field of photovoltaic cells, in particular to a contact structure of a solar cell, a preparation method and the solar cell.
Background
A solar cell is a semiconductor device that directly generates electricity using solar light, and is capable of converting light energy into electric energy through a photovoltaic effect. With the continuous development of solar cell technology, the recombination loss of metal contact areas becomes one of the important factors restricting the improvement of the conversion efficiency of solar cells.
In the prior art, when preparing a metal contact area, a passivation dielectric film is generally processed on the surface of a silicon substrate, then metal paste (silver paste, aluminum paste and the like) is printed on the passivation dielectric film, and the passivation dielectric film of the area printed with the metal paste on the silicon substrate is completely burnt through by a sintering process, so that the metal paste is directly contacted with the surface of the silicon substrate, and the metal contact area is obtained. The region where the passivation dielectric film is burnt out does not completely form ohmic contact, and there is a redundant region without the passivation dielectric film and ohmic contact, and the passivation dielectric film is lost at the part where the ohmic contact is not formed in the redundant region, so that the recombination of the metal contact region is increased, and the improvement of the conversion efficiency of the solar cell is limited.
Therefore, how to solve the problem of high recombination loss in the metal contact area of the solar cell in the prior art is an important technical problem to be solved by those skilled in the art.
Disclosure of Invention
The invention provides a contact structure of a solar cell, a preparation method and the solar cell, which are used for solving the defect of high recombination loss of a metal contact area of the solar cell in the prior art.
The invention provides a preparation method of a contact structure of a solar cell, which comprises the following steps:
depositing a passivation dielectric film on the surface of the silicon substrate;
coating metal slurry on a target area of the passivation dielectric film, wherein the metal slurry contains corrosion components capable of corroding the passivation dielectric film, a sintering process is adopted to reduce the thickness of the passivation dielectric film of the target area, the metal slurry forms an electrode grid line, and the thickness of the passivation dielectric film of the target area is larger than zero;
and applying a guiding charge on the electrode grid line, wherein the guiding charge is set to be different from the charge of unbalanced carriers which can be generated in the silicon substrate, and irradiating the passivation dielectric film of a non-target area by using a light source.
According to the preparation method of the contact structure of the solar cell, which is provided by the invention, a passivation dielectric film is deposited on the surface of a silicon substrate, and the preparation method comprises the following steps:
depositing a first dielectric film on the surface of the silicon substrate, wherein the first dielectric film is a silicon oxide dielectric film;
and depositing a second dielectric film on the surface of the first dielectric film, wherein the second dielectric film at least comprises a silicon nitride dielectric film.
According to the preparation method of the contact structure of the solar cell provided by the invention, before the second dielectric film is formed on the surface of the first dielectric film in a deposition mode, the preparation method further comprises the following steps:
and bombarding the first dielectric film by utilizing plasma so as to reduce the compactness degree of the first dielectric film.
According to the preparation method of the contact structure of the solar cell, the second dielectric film further comprises an alumina dielectric film, the second dielectric film is formed on the surface of the first dielectric film in a deposition mode, and the preparation method comprises the following steps:
depositing and forming the alumina dielectric film on the surface of the first dielectric film;
and depositing the silicon nitride dielectric film on the surface of the aluminum oxide dielectric film.
According to the preparation method of the contact structure of the solar cell, provided by the invention, the thickness of the passivation dielectric film of the target area is reduced by adopting a sintering process, and the preparation method comprises the following steps:
the sintering temperature is controlled so that the corrosive components in the metal slurry can only completely corrode the second dielectric film.
According to the preparation method of the contact structure of the solar cell, provided by the invention, the thickness of the first dielectric film is 1-5 nanometers, the thickness of the second dielectric film is 70-90 nanometers, and the sintering temperature is less than or equal to 650 ℃.
According to the preparation method of the contact structure of the solar cell, which is provided by the invention, before the passivation dielectric film is deposited on the surface of the silicon substrate, the preparation method further comprises the following steps:
and cleaning and polishing the surface of the silicon substrate.
According to the preparation method of the contact structure of the solar cell, the light source is a laser light source, an LED light source or a xenon lamp light source.
The invention also provides a contact structure of a solar cell, comprising:
a silicon substrate;
the passivation dielectric film is arranged on the surface of the silicon substrate;
the electrode grid line comprises a body part and a plurality of contact parts, wherein the body part and the contact parts are embedded in the passivation dielectric film, a space is reserved between the body part and the silicon substrate, the contact parts are positioned between the body part and the silicon substrate, the contact parts are in electric contact with the body part, and each contact part forms ohmic contact with the silicon substrate.
The invention also provides a solar cell, which comprises the contact structure of the solar cell.
In the preparation method of the contact structure of the solar cell, a passivation dielectric film is deposited on the surface of a silicon substrate, then metal slurry is coated on a target area of the passivation dielectric film, and then sintering treatment is carried out on the silicon substrate, the passivation dielectric film and the metal slurry. Because the metal slurry contains corrosion components capable of corroding the passivation dielectric film, the thickness of the passivation dielectric film in the target area can be reduced in the sintering treatment process. And finally, applying a guide charge which is different from the charge of the unbalanced carrier which can be generated in the silicon substrate on the electrode grid line, and irradiating the passivation dielectric film of the non-target area by utilizing a light source. Under the irradiation of a light source, non-equilibrium carriers are excited and induced in the silicon substrate, local current is formed under the action of guide charges, local high temperature is generated in the passivation dielectric film, the passivation dielectric film between the electrode grid line and the silicon substrate is burnt through locally to form a pinhole-shaped structure, the metal of the electrode grid line and the silicon substrate are mutually expanded at the pinhole-shaped structure until the metal of the electrode grid line contacts with the silicon substrate to form a metal contact area, and the metal contact area at the pinhole-shaped structure forms a conductive channel between the electrode grid line and the silicon substrate. In this way, the metal contact region is formed mainly by the local high temperature generated by the local current, so that the formed metal contact region is ohmic contact as a conductive channel. At the position where no local current is generated, local high temperature is not generated, correspondingly, a passivation dielectric film still exists at the position, and a metal contact area is not formed, so that the redundant area without the passivation dielectric film and ohmic contact is thoroughly eliminated, the recombination of the metal contact area can be reduced, the recombination loss of the contact structure of the solar cell is reduced, and the problem that the recombination loss of the metal contact area of the solar cell in the prior art is high is solved.
Drawings
In order to more clearly illustrate the invention or the technical solutions of the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the invention, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a flowchart of a method for manufacturing a contact structure of a solar cell according to the present invention;
fig. 2 is a schematic structural diagram of a contact structure of a solar cell according to the present invention.
Reference numerals:
1: a silicon substrate; 2: an electrode gate line; 21: a body portion; 22: a contact portion; 3: a first dielectric film; 4: and a second dielectric film.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The method of manufacturing the contact structure of the solar cell of the present invention is described below with reference to fig. 1 to 2.
As shown in fig. 1 and fig. 2, the method for manufacturing a contact structure of a solar cell according to an embodiment of the present invention mainly includes the following steps:
and 110, depositing a passivation dielectric film on the surface of the silicon substrate.
N-type monocrystalline silicon can be selected as the silicon substrate 1, and P-type monocrystalline silicon can be selected as the silicon substrate 1.
The passivation dielectric film may be a silicon nitride dielectric film, or may be a silicon oxide dielectric film or a silicon nitride dielectric film that is stacked.
The present embodiment mainly adopts a vapor deposition process (called PECVD process) based on plasma enhanced chemistry to plate a passivation dielectric film on the surface of the silicon substrate 1.
In the PECVD process, the gas containing the passivation dielectric film component atoms is ionized by the electrode portion in the PECVD chamber by means of microwaves or radio frequency, etc., plasma is locally formed, the chemical activity of the plasma is strong, the reaction is easy to occur, and the desired dielectric film is deposited on the silicon substrate 1.
It should be noted that, for those skilled in the art, the principle of the plating film by the PECVD process is mature prior art, and will not be described herein.
And 120, coating metal slurry on a target area of the passivation dielectric film, wherein the metal slurry contains corrosion components capable of corroding the passivation dielectric film, a sintering process is adopted to reduce the thickness of the passivation dielectric film of the target area, the metal slurry forms an electrode grid line, and the thickness of the passivation dielectric film of the target area is larger than zero.
After a passivation dielectric film is deposited and formed on the surface of the silicon substrate 1, metal slurry is coated at the position where the electrode grid line 2 needs to be formed, so that the electrode grid line 2 is formed through a sintering process.
The above-described position where the electrode gate line 2 needs to be formed is referred to as a target region.
And a screen printing technology can be selected to print metal paste on the passivation dielectric film, and at the moment, a screen stencil with a hollowed-out area corresponding to the target area is required to be selected.
The metal paste needs to contain an etching component capable of etching the passivation dielectric film to reduce the thickness of the passivation dielectric film in the target region by etching the passivation dielectric film during the sintering process.
In the sintering process, the sintering temperature and the sintering time need to be controlled to ensure that the residual thickness of the passivation dielectric film in the target area is within the range of 1-5 nanometers, so that the passivation dielectric film in the target area is prevented from being directly burnt through.
The sintering temperature needs to be controlled below 650 ℃.
The metal paste may be silver paste, aluminum paste or silver-aluminum paste mixed with glass frit, and the glass frit may be used as the etching component.
And 130, applying a guiding charge on the electrode grid line, wherein the guiding charge is set to be different from the charge of unbalanced carriers which can be generated in the silicon substrate, and irradiating the passivation dielectric film of the non-target area by utilizing a light source.
After the sintering process is completed, a guiding charge is applied to the formed electrode grid line, and the passivation dielectric film of the non-target area is irradiated by a light source.
The application of the pilot charge can be achieved by connecting an electrode to the electrode gate line 2, and the voltage formed is controlled to be 12V (V: volts, which is a unit of voltage).
If N-type monocrystalline silicon is selected as the silicon substrate 1, a positive electrode can be connected to the electrode grid line 2; if P-type monocrystalline silicon is selected as the silicon substrate 1, a negative electrode may be connected to the electrode gate line 2.
The light source can be a natural light source, or an artificial light source such as a laser light source, an LED light source or a xenon light source.
When a laser light source is selected as the light source, the illumination intensity of the laser light source can be controlled to be larger than or equal to 20 times of a solar constant, the power is 0.5W (W: watts, is a unit of power), the wavelength of the laser light source is 1062 nanometers, and the irradiation time can be 10 seconds.
After the light source irradiates the passivation dielectric film in the non-target region, unbalanced carriers are excited and induced in the silicon substrate 1. The aforementioned pilot charge needs to be different from the charge of the unbalanced carrier in the silicon substrate 1, and the pilot charge has an attracting effect on the unbalanced carrier in the silicon substrate 1, so that a local current can be formed. The guide charges are neutralized with unbalanced carriers in the silicon substrate 1, local high temperature can be generated in the passivation dielectric film, the passivation dielectric film between the electrode grid line 2 and the silicon substrate 1 is burnt through locally to form a pinhole-shaped structure, the metal of the electrode grid line 2 and the metal of the silicon substrate 1 mutually expand to the electrode grid line 2 at the pinhole-shaped structure are contacted with the silicon substrate 1 to form a metal contact area, and the metal contact area at the pinhole-shaped structure forms a conductive channel between the electrode grid line 2 and the silicon substrate 1.
In this way, the metal contact region is formed mainly by the local high temperature generated by the local current, so that the formed metal contact region is ohmic contact as a conductive channel. At the position where no local current is generated, local high temperature is not generated, correspondingly, a passivation dielectric film still exists at the position, and a metal contact area is not formed, so that the redundant area without the passivation dielectric film and ohmic contact is thoroughly eliminated, the recombination of the metal contact area can be reduced, the recombination loss of the contact structure of the solar cell is reduced, and the problem that the recombination loss of the metal contact area of the solar cell in the prior art is high is solved.
The passivation dielectric film may be a single-component dielectric film, for example, a silicon nitride dielectric film, and in this case, the silicon nitride dielectric film may be directly deposited on the silicon substrate 1.
Specifically, the silicon substrate 1 is placed in a PECVD chamber with SiH 4 And NH 3 For introducing intoSource and control SiH 4 The flow rate of (1) is 500-2000sccm (sccm is volume flow unit), and NH is controlled 3 The flow rate of the deposition process is 3000-10000sccm, and the power of the deposition process is 10000-15000W.
The passivation dielectric film may be a multi-component dielectric film, and when the passivation dielectric film includes two component dielectric films, the two component dielectric films are overlapped, the dielectric film near the surface of the silicon substrate 1 is a first dielectric film 3, and the dielectric film far from the surface of the silicon substrate 1 is a second dielectric film 4. At this time, it is necessary to deposit and form the first dielectric film 3 on the silicon substrate 1, and then deposit and form the second dielectric film 4 on the first dielectric film 3.
The first dielectric film 3 may be a silicon oxide dielectric film, and the second dielectric film 4 may be a silicon nitride dielectric film.
Specifically, the silicon substrate 1 is placed in a PECVD chamber with SiH 4 And N 2 O is a feed source and controls SiH 4 The flow rate of (2) is 400-2000sccm, and N is controlled 2 The flow of O is 5000-20000sccm, and the power of the deposition process is 10000-20000W. After the silicon oxide dielectric film is deposited, siH is used for 4 And NH 3 To feed in source and control SiH 4 The flow rate of (2) is 500-2000sccm, and NH is controlled 3 The flow rate of the deposition process is 3000-10000sccm, and the power of the deposition process is 10000-15000W.
The deposition time is also controlled during the deposition process to control the thickness of the silicon oxide dielectric film and the thickness of the silicon nitride dielectric film. The thickness of the silicon oxide dielectric film is generally controlled to be 1-5 nm, and in particular, the deposition time can be controlled to be 50-300 seconds. The thickness of the silicon nitride dielectric film is generally controlled to be 70-90 nm, and specifically, the deposition time can be controlled to be 70-1000 seconds.
When P-type single crystal silicon is selected as the silicon substrate 1, the second dielectric film 4 further includes an alumina dielectric film between the silicon nitride dielectric film and the silicon oxide dielectric film.
The aluminum oxide dielectric film may be formed by Atomic Layer Deposition (ALD).
In a specific embodiment, after deposition of the silicon oxide dielectric film is completed in the PECVD chamberThe silicon substrate 1 with the silicon oxide dielectric film deposited thereon was placed in an ALD apparatus as trimethylaluminum (chemical formula C 3 H 9 Al) and tetrachloropropene (also known as TMA, molecular formula C 3 H 2 Cl 4 ) For the supply of the source, the TMA flow rate was controlled to 1200sccm and the temperature was controlled to about 260 ℃.
The thickness of the alumina dielectric film may be 7 nm.
When the passivation dielectric film includes the first dielectric film 3 and the second dielectric film 4, only the sintering temperature may be controlled so that the etching component in the metal paste can only completely etch the second dielectric film 4.
The temperature required for the corrosive components in the metal slurry to corrode the silicon oxide dielectric film is higher than the temperature required for the corrosive components to corrode the silicon nitride dielectric film and the aluminum oxide dielectric film. The sintering temperature is controlled to be lower than the temperature required by the corrosion of the silicon oxide, so that the corrosion components in the metal slurry only corrode the silicon nitride dielectric film and the aluminum oxide dielectric film.
In a specific embodiment, the sintering temperature may be controlled to 650 degrees celsius or less during the sintering process. The corrosion component in the metal slurry only has corrosion effect on the silicon nitride dielectric film and the aluminum oxide dielectric film, and cannot corrode the silicon oxide dielectric film, so that the requirement on the control precision of the sintering time can be reduced, the silicon oxide dielectric film cannot be corroded even if the sintering time is too long, the burning-through of the passivation dielectric film can be effectively avoided, and the damage to the surface microstructure of the silicon substrate 1 can be avoided.
In the embodiment of the present invention, in order to improve the efficiency of forming the metal contact region by mutually expanding the metal of the electrode gate line 2 and the silicon substrate 1, the first dielectric film 3 may be a non-dense film. Specifically, before the second dielectric film 4 is formed by depositing on the surface of the first dielectric film 3, the first dielectric film 3 may be bombarded by Plasma, for example, a Plasma surface treatment process is used to perform surface treatment on the first dielectric film 3, so that the first dielectric film 3 forms a dielectric film with uniform pinholes, thereby reducing the densification degree of the first dielectric film 3, being beneficial to improving the speed of further forming a pinhole-shaped structure of the passivation dielectric film between the electrode grid line 2 and the silicon substrate 1 under the action of local current and local high temperature, improving the rate of forming ohmic contact, and improving the preparation efficiency of the contact structure of the solar cell.
In a specific embodiment, after the deposition of the first dielectric film 3 in the PECVD cavity is completed, argon or a mixture of argon and hydrogen is used as an inlet source, the power of the treatment process is 5000-15000W, and the bombardment time is controlled to be 10-200 seconds.
In order to ensure the deposition quality of the passivation dielectric film on the silicon substrate 1, in the embodiment of the present invention, the surface of the silicon substrate 1 needs to be cleaned and polished before the passivation dielectric film is deposited and formed.
In a specific embodiment, the silicon substrate 1 may be cleaned with an alkali solution and a hydrogen peroxide solution, and the silicon substrate 1 may be polished with an alkali solution and a surfactant.
The surfactant may be a texturing additive or a polishing additive. The kind of the surfactant used for polishing the silicon substrate 1 is well known to those skilled in the art, and the kind of the surfactant is not limited here.
The following describes the method for manufacturing the contact structure of the solar cell in the embodiment of the present invention in detail with reference to the above embodiments.
First embodiment:
adopting N-type monocrystalline silicon as a silicon substrate 1, cleaning the silicon substrate 1 by using an alkali solution and a hydrogen peroxide solution, and polishing the silicon substrate 1 by using the alkali solution and a surfactant;
placing the silicon substrate 1 in a PECVD chamber with SiH 4 And NH 3 To feed in source and control SiH 4 The flow rate of (2) is 900sccm, and NH is controlled 3 The flow rate of the silicon substrate is 7800sccm, the deposition time is 600 seconds, and a silicon nitride dielectric film with the thickness of 80 nanometers is formed on the surface of the silicon substrate 1 by adopting a PECVD process;
printing silver paste on the surface of a silicon nitride dielectric film by adopting a screen printing technology, then placing a silicon substrate 1 into a sintering furnace, controlling the sintering temperature to be 600 ℃, and controlling the sintering time to be 70 seconds, so that the thickness of the silicon nitride dielectric film between the silver paste and the silicon substrate 1 is 5 nanometers, wherein the silver paste forms an electrode grid line 2;
the positive electrode was connected to the electrode grid line 2, and the silicon nitride dielectric film was irradiated with a laser light source having a power of 0.5W and a wavelength of 1062 nm for 10 seconds.
The contact structure of the solar cell prepared by the above steps has a recombination loss of 149fA/cm 2 (fA/cm 2 Unit of dark saturation current density), the contact resistance was 1.9mΩ·cm 2 。
Specific embodiment II:
adopting N-type monocrystalline silicon as a silicon substrate 1, cleaning the silicon substrate 1 by using an alkali solution and a hydrogen peroxide solution, and polishing the silicon substrate 1 by using the alkali solution and a surfactant;
placing the silicon substrate 1 in a PECVD chamber with SiH 4 And N 2 O is a feed source and controls SiH 4 The flow rate of (2) is 1000sccm, and N is controlled 2 The flow of O is 7000sccm, the deposition time is 100 seconds, and a silicon oxide dielectric film with the thickness of 1.5 nanometers is formed on the surface of the silicon substrate 1 by adopting a PECVD process;
bombarding the silicon oxide dielectric film by taking a mixed gas of argon and hydrogen as an inlet source, wherein the bombardment time is 60 seconds;
by SiH 4 And NH 3 To feed in source and control SiH 4 The flow rate of (2) is 900sccm, and NH is controlled 3 The flow rate of the silicon oxide film is 7800sccm, the deposition time is 600 seconds, and a silicon nitride dielectric film with the thickness of 80 nanometers is formed on the surface of the silicon oxide dielectric film by adopting a PECVD process;
printing silver paste on the surface of a silicon nitride dielectric film by adopting a screen printing technology, then placing a silicon substrate 1 into a sintering furnace, controlling the sintering temperature to be 600 ℃, and controlling the sintering time to be 90 seconds, so that the silicon nitride dielectric film between the silver paste and the silicon substrate 1 is completely corroded, and only the silicon oxide dielectric film is reserved between the silver paste and the silicon substrate 1, wherein the silver paste forms an electrode grid line 2;
the positive electrode was connected to the electrode grid line 2, and the silicon nitride dielectric film was irradiated with a laser light source having a power of 0.5W and a wavelength of 1062 nm for 10 seconds.
The contact structure of the solar cell prepared by the above steps has a recombination loss of 146fA/cm 2 The contact resistance was 1.75mΩ·cm 2 。
Third embodiment:
adopting P-type monocrystalline silicon as a silicon substrate 1, cleaning the silicon substrate 1 by using an alkali solution and a hydrogen peroxide solution, and polishing the silicon substrate 1 by using the alkali solution and a surfactant;
placing the silicon substrate 1 in a PECVD chamber with SiH 4 And N 2 O is a feed source and controls SiH 4 The flow rate of (2) is 1500sccm, and N is controlled 2 The flow of O is 7000sccm, the deposition time is 150 seconds, and a silicon oxide dielectric film with the thickness of 3 nanometers is formed on the surface of the silicon substrate 1 by adopting a PECVD process;
bombarding the silicon oxide dielectric film by taking a mixed gas of argon and hydrogen as an inlet source, wherein the bombardment time is 60 seconds;
placing a silicon substrate 1 in ALD equipment, taking trimethylaluminum and tetrachloropropene as an inlet source, controlling the flow rate of the tetrachloropropene to 1200sccm, controlling the temperature to 260 ℃, and forming an alumina dielectric film with the thickness of 7 nanometers on the surface of a silica dielectric film by adopting an atomic layer deposition technology;
by SiH 4 And NH 3 To feed in source and control SiH 4 The flow rate of (2) is 900sccm, and NH is controlled 3 The flow rate of the silicon nitride film is 7800sccm, the deposition time is 600 seconds, and a silicon nitride dielectric film with the thickness of 80 nanometers is formed on the surface of the aluminum oxide dielectric film by adopting a PECVD process;
printing silver paste on the surface of a silicon nitride dielectric film by adopting a screen printing technology, then placing a silicon substrate 1 into a sintering furnace, controlling the sintering temperature to be 630 ℃, and controlling the sintering time to be 100 seconds, so that the silicon nitride dielectric film and an aluminum oxide dielectric film between the silver paste and the silicon substrate 1 are all corroded, and only the silicon oxide dielectric film is reserved between the silver paste and the silicon substrate 1, wherein the silver paste forms an electrode grid line 2;
the positive electrode was connected to the electrode grid line 2, and the silicon nitride dielectric film was irradiated with a laser light source having a power of 0.5W and a wavelength of 1062 nm for 10 seconds.
The contact structure of the solar cell prepared by the above steps has a recombination loss of 148fA/cm 2 The contact resistance was 1.8mΩ·cm 2 。
In conclusion, through repeated experiments, the contact resistance of the contact structure of the solar cell prepared by the preparation method of the contact structure of the solar cell provided by the embodiment of the invention is not higher than 2mΩ·cm 2 The composite loss is not higher than 150fA/cm 2 Only one third of the recombination losses of the contact structures of solar cells of the prior art.
On the other hand, based on the same general inventive concept, the embodiments of the present invention further provide a contact structure of a solar cell, and the contact structure of the solar cell described below and the method for manufacturing the contact structure of the solar cell described above may be referred to correspondingly to each other.
Referring to fig. 2, an embodiment of the present invention provides a contact structure of a solar cell, which includes a silicon substrate 1, a passivation dielectric film and a cell gate line, wherein the passivation dielectric film is disposed on a surface of the silicon substrate 1.
Specifically, the electrode gate line 2 includes a body portion 21 and a plurality of contact portions 22, the body portion 21 and the contact portions 22 are embedded in the passivation dielectric film, and a space is provided between the body portion 21 and the silicon substrate 1, that is, the body portion 21 does not penetrate through the passivation dielectric film.
The contact portion 22 is located between the body portion 21 and the silicon substrate 1, and the contact portion 22 is in electrical contact with the body portion 21 so as to allow a current to pass therethrough. Each contact portion 22 forms an ohmic contact with the silicon substrate 1.
So arranged, the metal contact area between the electrode gate line 2 and the silicon substrate 1 is realized by means of contact portions 22, each contact portion 22 forming an ohmic contact with the silicon substrate 1. The passivation dielectric film still exists at the position of the body part 21 except the contact part 22, and no metal contact area is formed, so that the redundant area without the passivation dielectric film and ohmic contact is thoroughly eliminated, and the recombination of the metal contact area can be reduced, thereby reducing the recombination loss of the contact structure of the solar cell and solving the problem of higher recombination loss of the metal contact area of the solar cell in the prior art.
The development process of the beneficial effects of the contact structure of the solar cell in the embodiment of the invention is substantially similar to that of the preparation method of the contact structure of the solar cell, so that the description thereof is omitted herein
In this embodiment, the passivation dielectric film may be a silicon nitride dielectric film alone, or may be a silicon nitride dielectric film and a silicon oxide dielectric film that are stacked, with the silicon oxide dielectric film being located between the silicon nitride dielectric film and the silicon substrate 1.
For the P-type monocrystalline silicon substrate 1, the passivation dielectric film may include an alumina dielectric film in addition to a silicon nitride dielectric film and a silicon oxide dielectric film, and the alumina dielectric film may be located between the silicon nitride dielectric film and the silicon oxide dielectric film.
In yet another aspect, based on the same general inventive concept, the embodiments of the present invention further provide a solar cell, including the contact structure of the solar cell provided in the above embodiments, which has all the advantages of the contact structure of the solar cell described above. The development process of the beneficial effects of the solar cell in the embodiment of the invention is substantially similar to that of the contact structure of the solar cell, so that the description thereof is omitted herein.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A method for manufacturing a contact structure of a solar cell, comprising:
depositing a passivation dielectric film on the surface of the silicon substrate;
coating metal slurry on a target area of the passivation dielectric film, wherein the metal slurry contains corrosion components capable of corroding the passivation dielectric film, a sintering process is adopted to reduce the thickness of the passivation dielectric film of the target area, the metal slurry forms an electrode grid line, and the thickness of the passivation dielectric film of the target area is larger than zero;
and applying a guiding charge on the electrode grid line, wherein the guiding charge is set to be different from the charge of unbalanced carriers which can be generated in the silicon substrate, and irradiating the passivation dielectric film of a non-target area by using a light source.
2. The method for manufacturing a contact structure of a solar cell according to claim 1, wherein depositing a passivation dielectric film on a surface of a silicon substrate comprises:
depositing a first dielectric film on the surface of the silicon substrate, wherein the first dielectric film is a silicon oxide dielectric film;
and depositing a second dielectric film on the surface of the first dielectric film, wherein the second dielectric film at least comprises a silicon nitride dielectric film.
3. The method for manufacturing a contact structure of a solar cell according to claim 2, wherein before the depositing the second dielectric film on the surface of the first dielectric film, the method further comprises:
and bombarding the first dielectric film by utilizing plasma so as to reduce the compactness degree of the first dielectric film.
4. The method for manufacturing a contact structure of a solar cell according to claim 2, wherein the second dielectric film further comprises an alumina dielectric film, and the depositing the second dielectric film on the surface of the first dielectric film comprises:
depositing and forming the alumina dielectric film on the surface of the first dielectric film;
and depositing the silicon nitride dielectric film on the surface of the aluminum oxide dielectric film.
5. The method of manufacturing a contact structure of a solar cell according to claim 2, wherein the reducing the thickness of the passivation dielectric film of the target region by a sintering process comprises:
the sintering temperature is controlled so that the corrosive components in the metal slurry can only completely corrode the second dielectric film.
6. The method of claim 5, wherein the first dielectric film has a thickness of 1-5 nm, the second dielectric film has a thickness of 70-90 nm, and the sintering temperature is less than or equal to 650 ℃.
7. The method for manufacturing a contact structure of a solar cell according to claim 1, wherein before the passivation dielectric film is formed on the surface of the silicon substrate by deposition, the method further comprises:
and cleaning and polishing the surface of the silicon substrate.
8. The method for manufacturing a contact structure of a solar cell according to claim 1, wherein the light source is a laser light source, an LED light source, or a xenon light source.
9. A contact structure of a solar cell, comprising:
a silicon substrate;
the passivation dielectric film is arranged on the surface of the silicon substrate;
the electrode grid line comprises a body part and a plurality of contact parts, wherein the body part and the contact parts are embedded in the passivation dielectric film, a space is reserved between the body part and the silicon substrate, the contact parts are positioned between the body part and the silicon substrate, the contact parts are in electric contact with the body part, and each contact part forms ohmic contact with the silicon substrate.
10. A solar cell comprising the solar cell contact of claim 9.
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| CN117374153A (en) * | 2023-09-28 | 2024-01-09 | 帝尔激光科技(无锡)有限公司 | Laser-induced sintering method for solar cell and solar cell |
| CN117878167A (en) * | 2023-09-28 | 2024-04-12 | 武汉帝尔激光科技股份有限公司 | Solar cell metallization method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117374153A (en) * | 2023-09-28 | 2024-01-09 | 帝尔激光科技(无锡)有限公司 | Laser-induced sintering method for solar cell and solar cell |
| CN117878167A (en) * | 2023-09-28 | 2024-04-12 | 武汉帝尔激光科技股份有限公司 | Solar cell metallization method |
| CN117374153B (en) * | 2023-09-28 | 2024-05-10 | 帝尔激光科技(无锡)有限公司 | Laser-induced sintering method for solar cell and solar cell |
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