CN116190488A - 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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- CN116190488A CN116190488A CN202211105400.XA CN202211105400A CN116190488A CN 116190488 A CN116190488 A CN 116190488A CN 202211105400 A CN202211105400 A CN 202211105400A CN 116190488 A CN116190488 A CN 116190488A
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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 System
-
- 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
- H01L31/0216—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
-
- 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
-
- 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
- H01L31/186—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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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; reducing the thickness of the passivation dielectric film of the target area by adopting an etching process, wherein the thickness of the passivation dielectric film of the target area is required to be larger than zero; coating metal slurry on a target area, and performing high-temperature drying treatment to enable the metal slurry to form an electrode grid line, wherein the metal slurry is set to be incapable of corroding a passivation dielectric film; 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;
reducing the thickness of the passivation dielectric film of the target area by adopting an etching process, wherein the thickness of the passivation dielectric film of the target area is required to be larger than zero;
coating metal paste on the target area, and performing high-temperature drying treatment to enable the metal paste to form an electrode grid line, wherein the metal paste is set to be incapable of corroding the passivation dielectric film;
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 method for manufacturing 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 an etching process, and the method comprises the following steps:
and coating an etching material on the target area of the passivation dielectric film, wherein the etching material is set as a silicon nitride etchant capable of selectively etching silicon nitride.
According to the preparation method of the contact structure of the solar cell, the thickness of the first dielectric film is 1-5 nanometers, and the thickness of the second dielectric film is 70-90 nanometers.
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, and then the thickness of the passivation dielectric film in a target area is reduced by adopting an etching process. At this time, it is required to ensure that the thickness of the passivation dielectric film in the target area after the etching is greater than zero, that is, to ensure that the passivation dielectric film in the target area cannot be completely etched. Then coating metal slurry on the target area, and carrying out high-temperature drying treatment to form the electrode grid line from the metal slurry. The metal slurry can not corrode the passivation dielectric film, so that the passivation dielectric film can be prevented from being damaged during high-temperature drying treatment, and the passivation dielectric film is prevented from being burnt. 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, reducing the thickness of the passivation dielectric film of the target area by adopting an etching process, wherein the thickness of the passivation dielectric film of the target area is required to be larger than zero.
After the passivation dielectric film is deposited on the surface of the silicon substrate 1, the electrode gate line 2 needs to be provided on the silicon substrate 1, and the position where the electrode gate line 2 needs to be formed is referred to as a target region.
Before the electrode gate line 2 is provided, the thickness of the passivation dielectric film in the target region needs to be reduced. In this embodiment, an etching process is used to reduce the thickness of the passivation dielectric film in the target area by etching the passivation dielectric film in the target area.
In the etching process, the etching process parameters need to be controlled, so that the thickness of the passivation dielectric film of the target area after the etching effect is ensured to be larger than zero, namely, the passivation dielectric film of the target area cannot be completely etched.
The thickness of the passivation dielectric film in the target area after etching is preferably controlled within the range of 1-5 nanometers.
And 130, coating metal paste on the target area, and performing high-temperature drying treatment to enable the metal paste to form electrode grid lines, wherein the metal paste is set to be incapable of corroding the passivation dielectric film.
After the thickness of the passivation dielectric film in the target area is reduced, the target area is coated with metal paste, and the metal paste is subjected to high-temperature drying treatment to form the electrode grid line 2.
The metal paste can be printed on the target area by adopting a screen printing technology, and at the moment, a screen stencil with a hollowed-out area corresponding to the target area is required to be selected.
The metal slurry does not contain corrosion components capable of corroding the passivation dielectric film, or the corrosion components capable of corroding the passivation dielectric film contained in the metal slurry are extremely polar, so that the passivation dielectric film is prevented from being damaged and burnt through during high-temperature drying treatment of the metal slurry.
The metal paste can be silver paste, aluminum paste or silver-aluminum paste, and contains glass powder with the content of less than 1%, or even contains no glass powder.
And 140, 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 electrode grid line 2 is processed, a guiding charge is applied to the formed electrode grid line 2, 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 To feed in source 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 chamber, the silicon substrate 1 with the silicon oxide dielectric film deposited thereon is placed in an ALD apparatus with trimethylaluminum (chemical formula C 3 H 9 Al) and tetrachloropropene (also called TMA, with molecular formula of C3H2Cl 4) are used as the inlet sources, the flow rate of TMA can be controlled to 1200sccm, and the temperature is controlled to be about 260 ℃.
The thickness of the alumina dielectric film may be 7 nm.
In this embodiment, the passivation dielectric film is etched by coating an etching material on the target region of the passivation dielectric film.
When the target area is coated with the etching material, a screen printing technology can be selected, and at the moment, a screen stencil with a hollowed-out area corresponding to the target area is needed to be selected.
The printing width of the etching material and the printing width of the metal paste need to be controlled so that the printing width of the metal paste is larger than the printing width of the etching material. In general, the printing width of the etching material can be controlled to be 5-20 microns, and the printing width of the metal paste can be controlled to be 5-30 microns.
The type of the etching material needs to be determined according to the type of the passivation dielectric film to be etched. Furthermore, during the etching process, it is necessary to control etching process parameters, such as temperature parameters, according to the kind of etching material and the kind of passivation dielectric film.
When the passivation dielectric film is only a silicon nitride dielectric film, a silicon nitride etchant capable of etching silicon nitride may be selected. The etching thickness of the desalted silicon dielectric film is controlled by controlling the using amount of the silicon nitride etchant and other parameters, so that the silicon nitride dielectric film is prevented from being completely etched.
When the passivation dielectric film is a silicon oxide dielectric film or a silicon nitride dielectric film, a silicon nitride etchant capable of selectively etching silicon nitride may be selected. The silicon nitride etchant can only etch the silicon nitride dielectric film, but cannot etch the silicon oxide dielectric film. Therefore, the silicon substrate 1 is cleaned after the silicon nitride dielectric film of the target area is completely etched without controlling the use amount of the etching material, and the residual silicon nitride etchant is removed.
When the passivation dielectric film is a silicon oxide dielectric film, an aluminum oxide dielectric film or a silicon nitride dielectric film, an etchant capable of selectively etching aluminum oxide and silicon nitride can be selected. The etchant can etch the silicon nitride dielectric film and the aluminum oxide dielectric film, and cannot etch the silicon oxide dielectric film. Therefore, the silicon substrate 1 is cleaned after the silicon nitride dielectric film and the aluminum oxide dielectric film in the target area are completely etched without controlling the use amount of etching materials, and the residual etchant is removed.
The etching material can be a transwell-N etchant, and the etchant is a pure reagent prepared from orthophosphoric acid, can realize selective etching of silicon nitride or aluminum oxide in the presence of silicon or silicon oxide, and has no adverse effect on exposed silicon and silicon dioxide basically. Not only the etching of the silicon oxide dielectric film but also 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.
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 (fA/cm 2 In units of dark saturation current density) is only one third of the recombination loss of the contact structure of the solar cell in 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;
reducing the thickness of the passivation dielectric film of the target area by adopting an etching process, wherein the thickness of the passivation dielectric film of the target area is required to be larger than zero;
coating metal paste on the target area, and performing high-temperature drying treatment to enable the metal paste to form an electrode grid line, wherein the metal paste is set to be incapable of corroding the passivation dielectric film;
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 for 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 using an etching process comprises:
and coating an etching material on the target area of the passivation dielectric film, wherein the etching material is set as a silicon nitride etchant capable of selectively etching silicon nitride.
6. The method of manufacturing a contact structure of a solar cell according to claim 2, wherein the thickness of the first dielectric film is 1-5 nm and the thickness of the second dielectric film is 70-90 nm.
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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| CN202211105400.XA CN116190488A (en) | 2022-09-09 | 2022-09-09 | Contact structure of solar cell, preparation method and solar cell |
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