Contact structure of solar cell, method of manufacturing and solar cell

Abstract

The application 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 following steps: depositing a passivation medium film on the surface of a silicon substrate; reducing the thickness of the passivation medium film in a target area by adopting an etching process, and the thickness of the passivation medium film in the target area must be greater than zero; coating metal paste on the target area, and performing high-temperature drying treatment so that the metal paste forms an electrode grid line, and the metal paste is arranged to be unable to corrode the passivation medium film; applying guided charges on the electrode grid line, the guided charges are arranged to be different from the charges of non-equilibrium carriers that can be generated in the silicon substrate, and a light source is used to irradiate the passivation medium film in a non-target area. In this way, the problem that the recombination loss of the metal contact area of the solar cell in the prior art is high is solved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell technology, and in particular to a contact structure, preparation method, and solar cell of a solar cell. Background Technology

[0002] A solar cell is a semiconductor device that generates electricity directly from sunlight, converting light energy into electrical energy through the photovoltaic effect. With the continuous development of solar cell technology, recombination losses at the metal contact area have become one of the key factors restricting the improvement of solar cell conversion efficiency.

[0003] In existing technologies, when preparing metal contact regions, a passivation dielectric film is typically first processed on the surface of a silicon substrate. Then, a metal paste (silver paste, aluminum paste, etc.) is printed onto the passivation dielectric film. Through a sintering process, the passivation dielectric film in the areas where the metal paste is printed on the silicon substrate is completely burned through, allowing the metal paste to directly contact the surface of the silicon substrate, thus forming the metal contact region. However, the burned-through areas do not fully form ohmic contacts; there are redundant regions with neither passivation dielectric film nor ohmic contacts. These redundant regions, lacking ohmic contacts, lose their passivation dielectric film, leading to increased recombination in the metal contact region and limiting the improvement of solar cell conversion efficiency.

[0004] Therefore, how to solve the problem of high recombination loss in the metal contact area of ​​solar cells in the prior art has become an important technical problem to be solved by those skilled in the art. Summary of the Invention

[0005] This invention provides a contact structure, fabrication method, and solar cell for a solar cell, thereby addressing the high recombination loss in the metal contact area of ​​existing solar cells.

[0006] This invention provides a method for preparing a contact structure for a solar cell, comprising:

[0007] A passivation dielectric film is deposited on the surface of a silicon substrate;

[0008] The thickness of the passivation dielectric film in the target area is reduced by an etching process, wherein the thickness of the passivation dielectric film in the target area must be greater than zero;

[0009] A metal paste is coated on the target area and then dried at high temperature to form electrode grid lines. The metal paste is configured not to corrode the passivation dielectric film.

[0010] A guiding charge is applied to the electrode gate line, the guiding charge being different from the charge of the non-equilibrium carriers that can be generated in the silicon substrate, and the passivation dielectric film in the non-target area is irradiated using a light source.

[0011] According to a method for fabricating a contact structure for a solar cell provided by the present invention, the step of depositing a passivation dielectric film on the surface of a silicon substrate includes:

[0012] A first dielectric film is deposited on the surface of the silicon substrate, wherein the first dielectric film is a silicon oxide dielectric film;

[0013] A second dielectric film is deposited on the surface of the first dielectric film to form a second dielectric film, the second dielectric film comprising at least a silicon nitride dielectric film.

[0014] According to a method for fabricating a contact structure of a solar cell provided by the present invention, before depositing a second dielectric film on the surface of the first dielectric film, the method further includes:

[0015] The first dielectric film is bombarded with plasma to reduce its density.

[0016] According to a method for fabricating a contact structure of a solar cell provided by the present invention, the second dielectric film further includes an alumina dielectric film, wherein the deposition of the second dielectric film on the surface of the first dielectric film comprises:

[0017] The alumina dielectric film is deposited on the surface of the first dielectric film;

[0018] The silicon nitride dielectric film is deposited on the surface of the alumina dielectric film.

[0019] According to a method for fabricating a contact structure for a solar cell provided by the present invention, the step of reducing the thickness of the passivation dielectric film in the target region by using an etching process includes:

[0020] An etching material is coated on the target area of ​​the passivation dielectric film, the etching material being configured as a silicon nitride etchant capable of selectively etching silicon nitride.

[0021] According to a method for preparing a contact structure for a solar cell provided by the present invention, the thickness of the first dielectric film is 1-5 nanometers and the thickness of the second dielectric film is 70-90 nanometers.

[0022] According to a method for fabricating a contact structure for a solar cell provided by the present invention, before depositing a passivation dielectric film on the surface of a silicon substrate, the method further includes:

[0023] The surface of the silicon substrate is cleaned and polished.

[0024] According to the present invention, a method for fabricating a contact structure of a solar cell is provided, wherein the light source is a laser light source, an LED light source, or a xenon lamp light source.

[0025] The present invention also provides a contact structure for a solar cell, comprising:

[0026] silicon substrate;

[0027] A passivation dielectric film is disposed on the surface of the silicon substrate;

[0028] An electrode grid line includes a body portion and a plurality of contact portions. The body portion and the contact portions are embedded in the passivation dielectric film. There is a gap between the body portion and the silicon substrate. The contact portions are located between the body portion and the silicon substrate and are in electrical contact with the body portion. Each of the contact portions forms an ohmic contact with the silicon substrate.

[0029] The present invention also provides a solar cell, including the contact structure of the solar cell described above.

[0030] In the method for fabricating the contact structure of a solar cell provided by this invention, a passivation dielectric film is first deposited on the surface of a silicon substrate, and then an etching process is used to reduce the thickness of the passivation dielectric film in the target area. At this point, it is necessary to ensure that the thickness of the passivation dielectric film in the target area after etching is greater than zero, that is, to ensure that the passivation dielectric film in the target area is not completely etched. Then, a metal paste is coated on the target area and subjected to high-temperature drying to form electrode grid lines. The aforementioned metal paste cannot corrode the passivation dielectric film, thus avoiding damage to the passivation dielectric film during high-temperature drying and preventing burn-through. Finally, a guiding charge, different from the charge of the non-equilibrium carriers that can be generated in the silicon substrate, is applied to the electrode grid lines, and the passivation dielectric film in the non-target area is irradiated using a light source. Under illumination, non-equilibrium carriers are excited and induced within the silicon substrate. Under the influence of the guiding charge, a local current is formed, generating localized high temperatures within the passivation dielectric film. This causes localized burn-through of the passivation dielectric film between the electrode grid lines and the silicon substrate, forming pinhole-like structures. The metal of the electrode grid lines and the silicon substrate diffuse into each other at these pinhole-like structures until they come into contact, forming metal contact regions. These metal contact regions at the pinhole-like structures constitute the conductive channels between the electrode grid lines and the silicon substrate. In this configuration, the formation of these metal contact regions relies primarily on the localized high temperatures generated by the local current; therefore, these metal contact regions, as conductive channels, are all ohmic contacts. In locations where no local current is generated, no localized high temperatures are also generated. Correspondingly, the passivation dielectric film still exists at these locations, and no metal contact regions are formed. This completely eliminates redundant regions lacking both passivation dielectric film and ohmic contacts, reducing recombination in the metal contact regions and thus lowering recombination losses in the contact structure of solar cells. This solves the problem of high recombination losses in the metal contact regions of existing solar cells. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a flowchart of a method for preparing the contact structure of a solar cell provided by the present invention;

[0033] Figure 2 This is a schematic diagram of the contact structure of the solar cell provided by the present invention.

[0034] Figure label:

[0035] 1: Silicon substrate; 2: Electrode gate line; 21: Body part; 22: Contact part; 3: First dielectric film; 4: Second dielectric film. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0037] The following is combined with Figures 1 to 2 A method for preparing the contact structure of the solar cell of the present invention is described.

[0038] like Figure 1 and Figure 2 As shown, the method for preparing the contact structure of a solar cell provided in this embodiment of the invention mainly includes the following steps:

[0039] Step 110: Deposit a passivation dielectric film on the surface of a silicon substrate.

[0040] N-type monocrystalline silicon or P-type monocrystalline silicon can be used as silicon substrate 1.

[0041] The passivation dielectric film mentioned above can be a silicon nitride dielectric film, or it can be an overlapping silicon oxide dielectric film and a silicon nitride dielectric film.

[0042] This embodiment mainly uses plasma-enhanced chemistry vapor deposition (PECVD) to deposit a passivation dielectric film on the surface of silicon substrate 1.

[0043] The PECVD process involves using microwaves or radio frequencies to ionize a gas containing atoms that form the passivation dielectric film at the electrodes within the PECVD chamber, creating a localized plasma. This plasma is highly chemically reactive and readily reacts, depositing the desired dielectric film onto the silicon substrate 1.

[0044] It should be noted that the principle of PECVD coating described above is a mature existing technology for those skilled in the art, and will not be elaborated here.

[0045] Step 120: Use an etching process to reduce the thickness of the passivation dielectric film in the target area. The thickness of the passivation dielectric film in the target area must be greater than zero.

[0046] After a passivation dielectric film is deposited on the surface of silicon substrate 1, electrode gate lines 2 need to be set on silicon substrate 1. The location where electrode gate lines 2 need to be formed is called the target area.

[0047] Before setting the electrode gate line 2, it is necessary to reduce the thickness of the passivation dielectric film in the target area. In this embodiment, an etching process is used to reduce the thickness of the passivation dielectric film in the target area by etching it.

[0048] It should be noted that during the etching process, it is necessary to control the etching process parameters to ensure that the thickness of the passivation dielectric film in the target area after etching is greater than zero, that is, to ensure that the passivation dielectric film in the target area cannot be completely etched.

[0049] Ideally, the thickness of the passivation dielectric film in the target area after etching should be controlled within the range of 1-5 nanometers.

[0050] Step 130: Coat the target area with metal paste and dry it at high temperature to form electrode grid lines. The metal paste is set to be non-corrosive to the passivation dielectric film.

[0051] After reducing the thickness of the passivation dielectric film in the target area, a metal paste is coated in the target area, and the metal paste is dried at high temperature to form electrode grid lines 2.

[0052] Metal paste can be printed on the target area using screen printing technology. In this case, a screen stencil with a cutout area corresponding to the target area needs to be selected.

[0053] The metal slurry does not contain corrosive components that can corrode the passivation medium film, or the corrosive components contained in the metal slurry that can corrode the passivation medium film are extremely low. During the high-temperature drying treatment of the metal slurry, damage to the passivation medium film should be avoided, and the passivation medium film should be prevented from being burned through.

[0054] The aforementioned metal paste can be silver paste, aluminum paste, or silver-aluminum paste, and its glass powder content is less than 1%, or even contains no glass powder.

[0055] Step 140: Apply a guiding charge to the electrode gate line. The guiding charge is set to be different from the charge of the non-equilibrium carriers that can be generated in the silicon substrate. Then, use a light source to irradiate the passivation dielectric film in the non-target area.

[0056] After the electrode grid line 2 is fabricated, a guiding charge is applied to the formed electrode grid line 2, and the passivation dielectric film in the non-target area is irradiated using a light source.

[0057] The application of the aforementioned guiding charge can be achieved by connecting electrodes to the electrode grid line 2, and the resulting voltage is controlled at 12V (V: volt, a unit of voltage).

[0058] If N-type single crystal silicon is selected as silicon substrate 1, a positive electrode can be connected on the electrode gate line 2; if P-type single crystal silicon is selected as silicon substrate 1, a negative electrode can be connected on the electrode gate line 2.

[0059] The aforementioned light source can be a natural light source, or an artificial light source such as a laser light source, LED light source, or xenon lamp light source.

[0060] When selecting a laser light source as the above-mentioned light source, the light intensity of the laser light source can be controlled to be greater than or equal to 20 times the solar constant, the power is 0.5W (W: watt, a unit of power), the wavelength of the laser light source is 1062 nanometers, and the irradiation time can be 10 seconds.

[0061] When the light source irradiates the passivation dielectric film in a non-target area, non-equilibrium carriers are excited and induced within the silicon substrate 1. The guiding charge must be different from the charge of the non-equilibrium carriers within the silicon substrate 1. The guiding charge attracts the non-equilibrium carriers within the silicon substrate 1, forming a local current. The neutralization of the guiding charge with the non-equilibrium carriers within the silicon substrate 1 generates localized high temperatures within the passivation dielectric film, causing localized burn-through of the passivation dielectric film between the electrode gate line 2 and the silicon substrate 1, forming a pinhole-like structure. The metal of the electrode gate line 2 and the silicon substrate 1 interpenetrate at the pinhole-like structure until they come into contact, forming a metal contact region. This metal contact region at the pinhole-like structure constitutes a conductive channel between the electrode gate line 2 and the silicon substrate 1.

[0062] With this configuration, the formation of the aforementioned metal contact areas relies primarily on the localized high temperatures generated by localized currents. Therefore, the metal contact areas formed here, acting as conductive channels, are all ohmic contacts. In locations where no localized currents are generated, no localized high temperatures are also generated. Correspondingly, a passivation dielectric film still exists at these locations, and no metal contact area forms. This completely eliminates redundant areas lacking both passivation dielectric films and ohmic contacts, reducing recombination in the metal contact areas and thus lowering recombination losses in the solar cell's contact structure. This solves the problem of high recombination losses in the metal contact areas of existing solar cells.

[0063] The passivation dielectric film mentioned above can be a single-component dielectric film, such as a silicon nitride dielectric film. In this case, the silicon nitride dielectric film can be directly deposited on the silicon substrate 1.

[0064] Specifically, silicon substrate 1 is placed in the PECVD chamber, with SiH4 and NH3 as the inlet sources, and the flow rate of SiH4 is controlled at 500-2000 sccm (sccm is a volumetric flow rate unit), the flow rate of NH3 is controlled at 3000-10000 sccm, and the power of the deposition process is 10000-15000W.

[0065] The passivation dielectric film described above can also be a dielectric film with multiple components. When the passivation dielectric film includes a dielectric film with two components, the two dielectric films are stacked, with the dielectric film closer to the surface of the silicon substrate 1 being the first dielectric film 3 and the dielectric film farther from the surface of the silicon substrate 1 being the second dielectric film 4. In this case, it is necessary to first 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.

[0066] The first dielectric film 3 can be a silicon oxide dielectric film, and the second dielectric film 4 can be a silicon nitride dielectric film.

[0067] Specifically, a silicon substrate 1 is placed in a PECVD chamber, using SiH4 and N2O as input sources. The flow rate of SiH4 is controlled at 400-2000 sccm, and the flow rate of N2O is controlled at 5000-20000 sccm. The deposition process power is 10000-20000W. After the deposition of the silicon oxide dielectric film is completed, SiH4 and NH3 are used as input sources, with the flow rate of SiH4 controlled at 500-2000 sccm and the flow rate of NH3 controlled at 3000-10000 sccm. The deposition process power is 10000-15000W.

[0068] The deposition process also requires controlling the deposition time to control the thickness of both the silicon oxide and silicon nitride dielectric films. The thickness of the silicon oxide dielectric film is typically controlled within 1-5 nanometers; specifically, the deposition time can be controlled between 50-300 seconds. The thickness of the silicon nitride dielectric film is typically controlled within 70-90 nanometers; specifically, the deposition time can be controlled between 70-1000 seconds.

[0069] When P-type single crystal silicon is selected as silicon substrate 1, the second dielectric film 4 mentioned above also includes an aluminum oxide dielectric film, which is located between the silicon nitride dielectric film and the silicon oxide dielectric film.

[0070] The aforementioned alumina dielectric film can be produced using atomic layer deposition (ALD) technology.

[0071] In a specific embodiment, after the deposition of the silicon oxide dielectric film is completed in the PECVD chamber, the silicon substrate 1 with the deposited silicon oxide dielectric film is placed in the ALD equipment. Trimethylaluminum (chemical formula C3H9Al) and tetrachloropropylene (also known as TMA, molecular formula C3H2Cl4) are used as the inlet sources. The flow rate of TMA can be controlled at 1200 sccm and the temperature can be controlled at about 260 degrees Celsius.

[0072] The thickness of the aforementioned alumina dielectric film can be 7 nanometers.

[0073] In this embodiment, the passivation dielectric film is etched by coating the target area of ​​the passivation dielectric film with an etching material.

[0074] When applying etching material to the target area, screen printing technology can be used. In this case, a screen printing plate with a perforated area corresponding to the target area needs to be selected.

[0075] It is necessary to control the printing width of both the etching material and the metal paste, ensuring that the printing width of the metal paste is greater than that of the etching material. Generally, the printing width of the etching material can be controlled within 5-20 micrometers, and the printing width of the metal paste within 5-30 micrometers.

[0076] The type of etching material mentioned above needs to be selected and determined based on the type of passivation dielectric film to be etched. Furthermore, during the etching process, etching process parameters, such as temperature parameters, need to be controlled according to the type of etching material and the type of passivation dielectric film.

[0077] When the passivation dielectric film is only a silicon nitride dielectric film, a silicon nitride etchant capable of etching silicon nitride can be selected. By controlling parameters such as the amount of silicon nitride etchant used, the etching thickness of the silicon nitride dielectric film can be controlled, preventing the silicon nitride dielectric film from being completely etched.

[0078] 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 can be selected. The silicon nitride etchant can only etch the silicon nitride dielectric film and cannot etch the silicon oxide dielectric film. Therefore, there is no need to control the amount of etching material used. After completely etching the silicon nitride dielectric film in the target area, the silicon substrate 1 is cleaned to remove any remaining silicon nitride etchant.

[0079] 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. This etchant can etch the silicon nitride dielectric film and the aluminum oxide dielectric film, but cannot etch the silicon oxide dielectric film. Therefore, there is no need to control the amount of etching material used. After completely etching the silicon nitride dielectric film and the aluminum oxide dielectric film in the target area, the silicon substrate 1 is cleaned to remove any remaining etchant.

[0080] The etching material mentioned above can be Transetch-N etchant, which is a pure reagent prepared with orthophosphoric acid. It can selectively etch silicon nitride or aluminum oxide in the presence of silicon or silicon oxide, and has virtually no adverse effect on the exposed silicon and silicon dioxide. This not only avoids etching of the silicon oxide dielectric film, but also avoids damage to the surface microstructure of the silicon substrate 1.

[0081] In this embodiment of the invention, to improve the efficiency of the metal-silicon substrate 1 inter-expansion formation of the metal contact region between the electrode grid line 2 and the metal, the first dielectric film 3 can be made into a non-dense film. Specifically, before the second dielectric film 4 is deposited on the surface of the first dielectric film 3, the first dielectric film 3 can be bombarded with plasma, for example, by using a plasma surface treatment process to treat the surface of the first dielectric film 3, so that the first dielectric film 3 forms a dielectric film with uniform pinholes, thereby reducing the density of the first dielectric film 3. This is beneficial to increasing the speed at which the passivation dielectric film between the electrode grid line 2 and the silicon substrate 1 further forms a pinhole structure under the action of local current and local high temperature, thereby increasing the rate of forming ohmic contacts and improving the fabrication efficiency of the contact structure of the solar cell.

[0082] In a specific embodiment, after the deposition of the first dielectric film 3 is completed in the PECVD chamber, argon or a mixture of argon and hydrogen is used as the inlet gas source, the power of the process is 5000-15000W, and the bombardment time is controlled at 10-200 seconds.

[0083] To ensure the deposition quality of the passivation dielectric film on the silicon substrate 1, in this embodiment of the invention, the surface of the silicon substrate 1 needs to be cleaned and polished before the passivation dielectric film is deposited.

[0084] In a specific embodiment, the silicon substrate 1 can be cleaned using an alkaline solution and a hydrogen peroxide solution, and polished using an alkaline solution and a surfactant.

[0085] The surfactants mentioned above can be texturing additives or polishing additives. For those skilled in the art, the types of surfactants used when polishing the silicon substrate 1 are mature existing technologies, and no limitation is made here on the types of surfactants.

[0086] After repeated experiments, the contact resistance of the solar cell contact structure prepared using the method provided in this embodiment of the invention is no higher than 2 mΩ·cm. 2 The composite loss is no higher than 150 fA / cm 2 (fA / cm 2 (The unit is dark saturation current density), which is only one-third of the recombination loss of the contact structure in existing solar cells.

[0087] On the other hand, based on the same general inventive concept, the embodiments of the present invention also provide a contact structure for a solar cell. The contact structure of the solar cell described below and the preparation method of the contact structure of the solar cell described above can be referred to in correspondence with each other.

[0088] Reference Figure 2 This invention provides a contact structure for a solar cell, including a silicon substrate 1, a passivation dielectric film, and cell grid lines, wherein the passivation dielectric film is disposed on the surface of the silicon substrate 1.

[0089] Specifically, the aforementioned 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 a passivation dielectric film, and there is a gap between the body portion 21 and the silicon substrate 1, that is, the body portion 21 does not penetrate the passivation dielectric film.

[0090] The aforementioned 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, allowing current to pass through. Each contact portion 22 forms an ohmic contact with the silicon substrate 1.

[0091] In this configuration, the metal contact area between the electrode grid line 2 and the silicon substrate 1 is achieved by the contact portion 22, and each contact portion 22 forms an ohmic contact with the silicon substrate 1. The body portion 21, except for the contact portion 22, still has a passivation dielectric film and does not form a metal contact area. This completely eliminates redundant areas that lack both a passivation dielectric film and ohmic contact, reducing recombination in the metal contact area and thus lowering the recombination loss of the solar cell's contact structure. This solves the problem of high recombination loss in the metal contact area of ​​existing solar cells.

[0092] The derivation process of the beneficial effects of the contact structure of the solar cell in the embodiments of the present invention is largely similar to the derivation process of the beneficial effects of the preparation method of the contact structure of the solar cell described above, and therefore will not be repeated here.

[0093] In this embodiment, the passivation dielectric film can be only a silicon nitride dielectric film, or it can be an overlapping silicon nitride dielectric film and a silicon oxide dielectric film, with the silicon oxide dielectric film located between the silicon nitride dielectric film and the silicon substrate 1.

[0094] For a silicon substrate 1 made of P-type single-crystal silicon, in addition to the silicon nitride dielectric film and the silicon oxide dielectric film, the passivation dielectric film may also include an aluminum oxide dielectric film, which is located between the silicon nitride dielectric film and the silicon oxide dielectric film.

[0095] On the other hand, based on the same general inventive concept, embodiments of the present invention also provide a solar cell, including the contact structure of the solar cell provided in the above embodiments, possessing all the advantages of the contact structure of the above-described solar cell. The derivation process of the beneficial effects of the solar cell in the embodiments of the present invention is largely similar to the derivation process of the beneficial effects of the contact structure of the above-described solar cell, and therefore will not be repeated here.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of fabricating a contact structure of a solar cell, characterized by, The method comprises the following steps: depositing a passivation medium film on the surface of a silicon substrate; reducing the thickness of the passivation medium film in a target area by etching, wherein the thickness of the passivation medium film in the target area must be greater than zero; coating a metal paste on the target area and performing high-temperature drying treatment so that the metal paste forms an electrode grid line, wherein the metal paste is configured to not corrode the passivation medium film; applying a guide charge on the electrode grid line, wherein the guide charge is configured to be different from the charge of the non-equilibrium carriers that can be generated in the silicon substrate, and a light source is used to irradiate the passivation medium film in a non-target area, wherein after the passivation medium film in the non-target area is irradiated by the light source, the non-equilibrium carriers in the silicon substrate are excited and induced, the guide charge has an attractive effect on the non-equilibrium carriers in the silicon substrate to form a local current, the guide charge and the non-equilibrium carriers in the silicon substrate are neutralized, a local high temperature is generated in the passivation medium film, the passivation medium film between the electrode grid line and the silicon substrate is locally burned through to form a pinhole structure, the metal of the electrode grid line and the silicon substrate are mutually expanded at the pinhole structure to contact each other to form a metal contact area, and the metal contact area constitutes a conductive channel between the electrode grid line and the silicon substrate.

2. The method of producing a contact structure of a solar cell according to claim 1, wherein The step of depositing a passivation medium film on the surface of a silicon substrate comprises the following steps: depositing a first medium film on the surface of the silicon substrate, wherein the first medium film is a silicon oxide medium film; depositing a second medium film on the surface of the first medium film, wherein the second medium film at least comprises a silicon nitride medium film.

3. The method of producing a contact structure of a solar cell according to claim 2, wherein Before the step of depositing a second medium film on the surface of the first medium film, the method further comprises the following step: bombarding the first medium film by plasma to reduce the density of the first medium film.

4. The method of producing a contact structure of a solar cell according to claim 2, wherein The second medium film further comprises a silicon aluminum oxide medium film, and the step of depositing a second medium film on the surface of the first medium film comprises the following steps: depositing the silicon aluminum oxide medium film on the surface of the first medium film; depositing the silicon nitride medium film on the surface of the silicon aluminum oxide medium film.

5. The method of claim 2, wherein the method further comprises: The step of reducing the thickness of the passivation medium film in the target area by etching comprises the following step: coating an etching material on the target area of the passivation medium film, wherein the etching material is configured to be a silicon nitride etchant that can selectively etch silicon nitride.

6. The method of producing a contact structure of a solar cell according to claim 2, wherein The thickness of the first medium film is 1-5 nanometers, and the thickness of the second medium film is 70-90 nanometers.

7. The method of producing a contact structure of a solar cell according to claim 1, wherein Before the step of depositing a passivation medium film on the surface of a silicon substrate, the method further comprises the following steps: cleaning and polishing the surface of the silicon substrate.

8. The method of producing 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 lamp light source.

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