Solar cell and method of manufacture thereof, photovoltaic assembly

Abstract

To provide a solar cell and a method of manufacture thereof, and a photovoltaic assembly.SOLUTION: A solar cell includes a silicon substrate, a tunnel oxide layer is provided on the surface of the silicon substrate, a first doped polysilicon layer is provided on the surface of the tunnel oxide layer, the surface of the first doped polysilicon layer includes a metal contact region provided with a laser light absorption layer capable of absorbing laser light of a set wavelength and vaporizing, and a non-metal contact region, and a second doped polysilicon layer is provided on the surface of the laser light absorption layer. By disposing the second doped polysilicon layer only on the metal contact region, the solar cell can realize a passivation contact and can reduce the blocking and absorption of light in the non-metal contact region, thereby increasing the light utilization rate and cell efficiency. By providing the laser light absorption layer, the laser light absorption layer and the second doped polysilicon layer in the non-metal contact region can be removed by laser light, effectively simplifying the manufacturing process.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present application relates to the technical field of solar cells, and in particular to solar cells and their manufacturing methods, and photovoltaic assemblies. [Background technology]

[0002] With the development of solar cell technology, tunnel oxide passivation contact technology has emerged, which is formed by forming an ultra-thin tunnel oxide layer on the surface of crystalline silicon, and then stacking a doped polysilicon layer on the tunnel oxide layer to form a passivation contact structure, which can significantly reduce the recombination in the metal contact area, has good contact performance, and can effectively improve the efficiency of the solar cell. However, the polysilicon layer in the passivation contact structure has serious parasitic absorption of light, so that growing a thick polysilicon layer over the entire surface of the silicon wafer will greatly reduce the light utilization rate of the cell, reduce the short circuit current of the cell, and bring about a certain current loss, which limits the further improvement of the open circuit voltage and conversion efficiency of the solar cell.

[0003] In the related art, the polysilicon layer and tunnel oxide layer underneath the metal electrode are left intact, and multiple film layers that do not function as passivation contacts in other regions are removed to form a selective polysilicon thin film passivation contact structure, thereby realizing the function of the passivation contact and eliminating the effect of light absorption by non-metallic regions, thereby further improving the efficiency of the solar cell.

[0004] However, the current method for manufacturing a selective polysilicon thin film passivation contact structure has problems such as complicated process and high cost, which does not allow for large-scale production and limits its industrial spread. Summary of the Invention [Problem to be solved by the invention]

[0005] In view of this, there is a need to provide a solar cell and a method for fabricating the same, and a photovoltaic assembly, which address the problems of complicated process and high cost in the current fabrication methods of selective polysilicon thin film passivation contact structures. [Means for solving the problem]

[0006] A first aspect is a solar cell, A silicon substrate; a tunnel oxide layer provided on a surface of the silicon substrate; a first doped polysilicon layer provided on a surface of the tunnel oxide layer, the surface of the first doped polysilicon layer including a metal contact region and a non-metal contact region; a laser light absorption layer provided in the metal contact region on the surface of the first doped polysilicon layer, capable of absorbing laser light having a set wavelength and vaporizing the laser light; a second doped polysilicon layer provided on a surface of the laser light absorption layer.

[0007] In one embodiment, the tunnel oxide layer comprises a silicon dioxide layer and / or the thickness of the tunnel oxide layer is less than 3 nm.

[0008] In an embodiment, the laser light absorption layer comprises a titanium oxide layer or an aluminum oxide layer, and / or the thickness range of the laser light absorption layer comprises 1 nm to 5 nm.

[0009] In one embodiment, the thickness of the second doped polysilicon layer is greater than the thickness of the first doped polysilicon layer.

[0010] In an embodiment, the first doped polysilicon layer comprises a phosphorus-doped polysilicon thin film or a boron-doped polysilicon thin film, and / or the thickness range of the first doped polysilicon layer comprises 5 nm to 100 nm.

[0011] In an embodiment, the second doped polysilicon layer comprises a phosphorus-doped polysilicon thin film or a boron-doped polysilicon thin film, and / or the thickness range of the second doped polysilicon layer comprises 70 nm to 200 nm.

[0012] In one embodiment, the selective passivation contact structure further includes a passivation anti-reflection layer and a metal electrode, the passivation anti-reflection layer being disposed on the non-metal contact region at the surface of the first doped polysilicon layer and on the surface of the second doped polysilicon layer, and the metal electrode being fixedly connected to the second doped polysilicon layer.

[0013] In one embodiment, the passivation anti-reflection layer comprises a silicon nitride layer or a stack of an aluminum oxide layer and a silicon nitride layer, and / or the thickness range of the passivation anti-reflection layer comprises 70 nm to 80 nm.

[0014] A second aspect is a method for producing the solar cell according to any one of the first aspects, comprising the steps of: Providing a silicon substrate; forming a tunnel oxide layer on a surface of the silicon substrate; forming a first doped polysilicon layer on a surface of the tunnel oxide layer; forming a laser light absorption layer on a surface of the first doped polysilicon layer; forming a second doped polysilicon layer on a surface of the laser light absorption layer; removing the laser light absorption layer and the second doped polysilicon layer in a non-metal contact region on the surface of the first doped polysilicon layer with laser light of a set wavelength to expose the non-metal contact region on the surface of the first doped polysilicon layer, thereby obtaining the solar cell.

[0015] In one embodiment, the laser light includes an ultraviolet picosecond laser light, and the set wavelength range includes 355 nm to 532 nm.

[0016] In one embodiment, the method comprises the steps of: forming a passivation anti-reflective layer on the non-metal contact region at the surface of the first doped polysilicon layer and on the surface of the second doped polysilicon layer; The method further includes forming a metal electrode on the passivation anti-reflective layer in an area corresponding to the second doped polysilicon layer.

[0017] A third aspect is a photovoltaic assembly comprising a solar cell according to any one of the first aspects. Effect of the Invention

[0018] The solar cell and the manufacturing method thereof can realize the function of passivation contact by disposing the second doped polysilicon layer only in the metal contact region, and can improve the light utilization rate by reducing the light blocking and absorption of the nonmetal contact region and reduce the current loss of the solar cell, thereby effectively reducing the recombination between the metal and nonmetal contact regions, guaranteeing the light utilization rate of the cell, and having good contact performance, and can effectively improve the efficiency of the solar cell. In addition, by disposing the laser light absorption layer between the first doped polysilicon layer and the second doped polysilicon layer, the laser light absorption layer and the second doped polysilicon layer in the nonmetal contact region can be removed by utilizing the action of the laser light absorption layer strongly absorbing the laser light and vaporizing it without using a mask or chemical etching process, thereby effectively simplifying the process of manufacturing the solar cell, and by adding a laser light etching device, the process is compatible with the mass production process of conventional crystalline silicon solar cells, the process cost is low, it is easy to be widely used on a large scale, and it can be mass-produced quickly, and the problem of the complicated process and high cost in the current manufacturing method of the selective polysilicon thin film passivation contact structure can be effectively solved. [Brief description of the drawings]

[0019] [Figure 1] 1 is a schematic diagram of a solar cell according to an embodiment of the present application; [Diagram 2] 1 is a flowchart of a method for manufacturing a solar cell in one embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] In order to make the above objects, features, and advantages of the present application more clearly understood, the following detailed description of specific embodiments of the present application will be given with reference to the drawings. In order to fully understand the present application, many specific details are described in the following description. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application, and therefore the present application is not limited to the specific embodiments disclosed below.

[0021] In the description of this application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like are shown based on the drawings and are intended only to facilitate and simplify the description of the application, and do not imply or suggest that the devices or elements referred to have a particular orientation or must be constructed or operated in a particular orientation, and should not be construed as limiting the application.

[0022] Also, the drawings are for illustrative purposes only and are not drawn to scale, and different membrane layers or regions may be shown in a single drawing to an enlarged or reduced size. The terms "first" and "second" are used for illustrative purposes only and should not be understood as indicating or suggesting the relative importance or implying the number of technical features indicated. Thus, a feature qualified by "first" or "second" may explicitly or implicitly include at least one of the feature. In the present description, "plurality" means at least two, e.g., two, three, etc., unless expressly defined otherwise.

[0023] In the description of this application, the terms "attached", "connected", "connected", "fixed" and the like should be understood in a broad sense unless otherwise clearly specified and limited. Unless otherwise clearly limited, for example, it may be a fixed connection, a detachable connection, or it may be integrated. It may also be a mechanical connection or an electrical connection. It may also be a direct connection, an indirect connection via an intermediate medium, an internal communication between two elements, or a mutual interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific situation.

[0024] In this application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first feature and the second feature are in direct contact with each other, or that the first feature and the second feature are in indirect contact with each other via an intermediate medium. Furthermore, a first feature being "above," "above," and "on the upper surface" of a second feature may simply mean that the first feature is directly above or diagonally above the second feature, or that the horizontal height of the first feature is greater than that of the second feature. A first feature being "below," "below," and "on the lower surface" of a second feature may simply mean that the first feature is directly below or diagonally below the second feature, or that the horizontal height of the first feature is smaller than that of the second feature.

[0025] As an explanation, when an element is referred to as being "fixed" or "mounted" on another element, it may be directly disposed on the other element, or there may be intervening elements. When an element is referred to as being "connected" to another element, it may be directly connected to the other element, or there may be intervening elements. As used herein, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar terms are for illustrative purposes only and do not represent the only embodiment.

[0026] In crystalline silicon solar cells, there is serious recombination in the contact area between the metal electrode and the surface of the crystalline silicon, and the recombination current is too large, which is a factor that limits the improvement of the efficiency of crystalline silicon solar cells. The tunnel oxide passivation contact structure is composed of a single ultra-thin tunnel oxide layer and a doped polysilicon layer, which can significantly reduce the recombination in the metal contact area and has good contact performance, and can greatly improve the efficiency of solar cells.

[0027] In the passivation contact structure of a solar cell, the polysilicon layer has serious parasitic absorption of light, so if a thick polysilicon layer is grown over the entire surface of a silicon wafer, the light utilization rate of the cell will be greatly reduced, and the short circuit current of the cell will be reduced, resulting in a certain current loss. Effectively reducing the recombination in the metal-nonmetal contact area while ensuring the light utilization rate of the cell has become a problem that needs to be solved.

[0028] In order to further improve the efficiency of the solar cell, the polysilicon layer and the tunnel oxide layer underneath the metal electrode can be left intact, and multiple film layers that do not function as passivation contacts in other areas can be removed, thereby realizing the function of passivation contacts and eliminating the effect of light absorption by non-metallic areas. This structure is called a selective polysilicon thin film passivation contact structure.

[0029] In the current selective polysilicon thin film passivation contact structure and its manufacturing method, the selective polysilicon thin film passivation contact structure is generally formed by removing the polysilicon thin film in the non-metal contact area by chemical etching, or depositing the polysilicon thin film only in the metal contact area by using a mask, etc. The process of the above technical means is complicated and expensive, which is not suitable for large-scale production and limits its industrial popularization.

[0030] Referring to FIG. 1, FIG. 1 shows a schematic diagram of a solar cell in one embodiment of the present application, and the solar cell 100 provided in one embodiment of the present application includes a silicon substrate 1, a tunnel oxide layer 2, a first doped polysilicon layer 3, a laser light absorption layer 4, and a second doped polysilicon layer 5. The tunnel oxide layer 2 is provided on the surface of the silicon substrate 1. The first doped polysilicon layer 3 is provided on the surface of the tunnel oxide layer 2, and the surface of the first doped polysilicon layer 3 includes a metal contact region and a non-metal contact region. The laser light absorption layer 4 is provided in the metal contact region on the surface of the first doped polysilicon layer 3, and can absorb laser light of a set wavelength and vaporize it. The second doped polysilicon layer 5 is provided on the surface of the laser light absorption layer 4.

[0031] In this embodiment, a silicon substrate 1 is used to manufacture a solar cell 100, and the silicon substrate 1 may be a silicon wafer, and the silicon wafer may be a single crystal silicon wafer or a polycrystalline silicon wafer, and the doping type of the silicon wafer surface may be P-type or N-type. The silicon substrate 1 has a front surface and a back surface arranged opposite to each other, and the front surface (i.e., the light receiving surface) faces the sun, and the back surface (i.e., the backlight surface) faces away from the sun. The front surface of the silicon substrate 1 may be the front surface of the silicon substrate 1 or the back surface of the silicon substrate 1, and is not limited here.

[0032] The surface of the silicon substrate 1, the surface of the tunnel oxide layer 2, the surface of the first doped polysilicon layer 3, the surface of the laser light absorption layer 4, and the surface of the second doped polysilicon layer 5 are not adjacent to one another.

[0033] The tunnel oxide layer 2 and the first doped polysilicon layer 3 are sequentially provided over the entire surface of the silicon substrate 1, and together form a passivation contact structure to provide good surface passivation for the surface of the silicon substrate 1, thereby reducing surface recombination. The tunnel oxide layer 2 is very thin and the first doped polysilicon layer 3 is doped, so that majority carriers can penetrate the two passivation layers, while minority carriers are blocked, and thus a passivation contact can be obtained without openings by metallizing the surface of the first doped polysilicon layer 3. The surface of the first doped polysilicon layer 3 includes a metal contact region, which is a region for achieving a passivation contact, and a non-metal contact region, which is another region that does not need to play the role of a passivation contact.

[0034] The laser light absorption layer 4 and the second doped polysilicon layer 5 are sequentially stacked on the metal contact region on the surface of the silicon substrate 1, so that two doped polysilicon thin films, the first doped polysilicon layer 3 and the second doped polysilicon layer 5, exist simultaneously in the metal contact region, so that the metal contact region has a thicker passivation contact structure, the passivation level of the metal contact region is effectively improved, and the effect of the passivation contact can be prevented from being destroyed by the metal electrode during metallization, so that the recombination of the metal contact region can be significantly reduced and good contact performance can be achieved.

[0035] In addition, since the second doped polysilicon layer 5 is provided only in the metal contact region of the passivation contact, and only the first doped polysilicon layer 3 is provided in the non-metal contact region where no passivation contact is required, a thinner polysilicon thin film is present in the non-metal contact region, and a selective polysilicon thin film passivation contact structure is formed, which can reduce the blocking and absorption of light in the non-metal contact region, improve the light utilization rate, prevent current loss in the solar cell 100, and improve the efficiency of the solar cell 100.

[0036] Furthermore, a laser light absorbing layer 4 is provided between the two doped polysilicon thin films in the metal contact region, and the laser light absorbing layer 4 can be an oxide thin film having a tunnel effect so as to ensure the effect of passivation contact. Also, the laser light absorbing layer 4 can absorb a laser light of a set wavelength and vaporize it, so that the laser light absorbing layer 4 and the second doped polysilicon layer 5 located on the surface of the laser light absorbing layer 4 can be removed by laser light etching using the effect of the laser light absorbing layer 4 strongly absorbing the laser light and vaporizing it.

[0037] In the method for forming solar cell 100 of this embodiment, first, a tunnel oxide layer 2, a first doped polysilicon layer 3, a laser light absorption layer 4 and a second doped polysilicon layer 5 are formed in this order over the entire surface of silicon substrate 1, and then, by utilizing the action of laser light absorption layer 4 strongly absorbing laser light and vaporizing it, the laser light absorption layer 4 and the second doped polysilicon layer 5 in the non-metal contact region are removed by laser light etching, so that solar cell 100 of this embodiment can be finally formed.

[0038] In the solar cell 100 of the embodiment of the present application, by disposing the second doped polysilicon layer 5 only in the metal contact region, the function of passivation contact can be realized, and the light blocking and absorption in the non-metal contact region can be reduced to improve the light utilization rate and reduce the current loss of the solar cell 100. Thus, the recombination between the metal and non-metal contact regions can be effectively reduced, while ensuring the light utilization rate of the solar cell 100, and also having good contact performance, effectively improving the efficiency of the solar cell 100. In addition, by disposing the laser light absorption layer 4 between the first doped polysilicon layer 3 and the second doped polysilicon layer 5, it is possible to remove the laser light absorption layer 4 and the second doped polysilicon layer 5 in the non-metal contact region by utilizing the action of the laser light absorption layer 4 strongly absorbing laser light and vaporizing it without using a mask or chemical etching process, which effectively simplifies the process of manufacturing the solar cell 100. By adding a laser light etching device, the process becomes compatible with the mass production process of the conventional crystalline silicon solar cell 100, the process cost is low, it is easy to be widely used, and mass production can be performed quickly, which effectively solves the problems of complicated process and high cost in the current manufacturing method of the selective polysilicon thin film passivation contact structure.

[0039] In some embodiments, the tunnel oxide layer 2 may include a silicon dioxide layer.

[0040] In some embodiments, the thickness of the tunnel oxide layer 2 is less than 3 nm to satisfy the quantum tunneling effect. Alternatively, the thickness range of the tunnel oxide layer 2 may include 0.5 nm to 2.5 nm. Furthermore, the thickness range of the tunnel oxide layer 2 may include 1 nm to 2.5 nm, for example, the thickness of the tunnel oxide layer 2 may be 1.5 nm.

[0041] In some embodiments, the laser light absorption layer 4 includes a titanium oxide layer or an aluminum oxide layer. Titanium oxide and aluminum oxide can strongly absorb 355 nm laser light and be vaporized by the action of the laser light, so that the laser light absorption layer 4 and the second doped polysilicon layer 5 in the nonmetal contact region can be quickly removed by scanning the nonmetal contact region with 355 nm ultraviolet picosecond laser light, which has a simple process flow, low cost, and easy large-scale popularization.

[0042] Preferably, the thickness range of the laser light absorption layer 4 may include 1 nm to 5 nm so as to satisfy the quantum tunneling effect.

[0043] Furthermore, the thickness range of the laser light absorption layer 4 may include 1 nm to 3 nm, and for example, the thickness of the titanium oxide thin film of the laser light absorption layer 4 may be 3 nm.

[0044] In some embodiments, the thickness of the second doped polysilicon layer 5 is greater than the thickness of the first doped polysilicon layer 3. The second doped polysilicon layer 5 located in the metal contact region has a greater thickness, which can further prevent the passivation contact effect from being destroyed by the metal electrode, and significantly reduce the recombination in the metal contact region; on the other hand, the first doped polysilicon layer 3 located in the non-metal contact region has a smaller thickness, which can further reduce the light blocking and absorption in the non-metal contact region, improve the light utilization rate, and realize the compatibility between the full passivation of the passivation contact structure and the light absorption and metal electrode penetration damage, which is favorable to further improve the efficiency of the solar cell 100.

[0045] In some embodiments, the first doped polysilicon layer 3 comprises a phosphorus-doped polysilicon thin film or a boron-doped polysilicon thin film. When the silicon substrate 1 is an N-type silicon wafer, the first doped polysilicon layer 3 is located on the surface of the silicon substrate 1 that is an N-type silicon wafer, and is preferably a phosphorus-doped polysilicon thin film. When the silicon substrate 1 is a P-type silicon wafer, the first doped polysilicon layer 3 is located on the surface of the silicon substrate 1 that is a P-type silicon wafer, and is preferably a boron-doped polysilicon thin film.

[0046] In some embodiments, the thickness range of the first doped polysilicon layer 3 includes 5 nm to 100 nm. Further, the thickness range of the first doped polysilicon layer 3 includes 10 nm to 50 nm, for example, the thickness of the first doped polysilicon layer 3 is 20 nm.

[0047] In some embodiments, the second doped polysilicon layer 5 comprises a phosphorus-doped polysilicon thin film or a boron-doped polysilicon thin film. When the silicon substrate 1 is an N-type silicon wafer, the first doped polysilicon layer 3 is located on the surface of the silicon substrate 1 that is an N-type silicon wafer, and is preferably a phosphorus-doped polysilicon thin film. When the silicon substrate 1 is a P-type silicon wafer, the first doped polysilicon layer 3 is located on the surface of the silicon substrate 1 that is a P-type silicon wafer, and is preferably a boron-doped polysilicon thin film.

[0048] In some embodiments, the thickness range of the second doped polysilicon layer 5 includes 70 nm to 200 nm. Further, the thickness range of the second doped polysilicon layer 5 includes 100 nm to 150 nm, for example, the thickness of the second doped polysilicon layer 5 is 150 nm.

[0049] In some embodiments, as shown in FIG. 1, the solar cell 100 further includes a passivation anti-reflection layer 6 and a metal electrode 7. The passivation anti-reflection layer 6 is provided on the non-metal contact region on the surface of the first doped polysilicon layer 3 and on the surface of the second doped polysilicon layer 5. The metal electrode 7 is fixedly connected to the second doped polysilicon layer 5. The passivation anti-reflection layer 6 is used to provide field passivation, and can reduce the reflection of incident light and increase optical absorption, thereby further improving the light utilization rate and improving the efficiency of the solar cell 100. The metal electrode 7 is fixedly connected to the second doped polysilicon layer 5 through the passivation anti-reflection layer 6, thereby realizing a conductive connection between the metal electrode 7 and the second doped polysilicon layer 5. The metal electrode 7 is used to collect current.

[0050] In some embodiments, the passivation anti-reflective layer 6 may include a silicon nitride layer or a stack of an aluminum oxide layer and a silicon nitride layer. In some embodiments, the thickness range of the passivation anti-reflective layer 6 includes 70 nm to 80 nm.

[0051] In some embodiments, the metal electrode 7 may include a silver electrode or a silver aluminum electrode.

[0052] FIG. 2 shows a flow chart of a method for manufacturing a solar cell in one embodiment of the present application. The method for manufacturing a solar cell provided in one embodiment of the present application is a method for manufacturing a solar cell in any of the above-mentioned embodiments, Step S100 of providing a silicon substrate; Step S200 of fabricating a tunnel oxide layer on a surface of a silicon substrate; Step S300: forming a first doped polysilicon layer on a surface of the tunnel oxide layer; Step S400: forming a laser light absorption layer on a surface of the first doped polysilicon layer; Step S500 of forming a second doped polysilicon layer on a surface of the laser light absorption layer; and step S600 of removing the laser light absorption layer and the second doped polysilicon layer in the non-metal contact region on the surface of the first doped polysilicon layer with laser light of a set wavelength to expose the non-metal contact region on the surface of the first doped polysilicon layer to obtain a solar cell.

[0053] In this embodiment, the laser light of the set wavelength refers to a laser light that can be strongly absorbed by the laser light absorption layer and vaporize the laser light absorption layer. For example, the laser light may be an ultraviolet picosecond laser light or an ultraviolet nanosecond laser light. When manufacturing a solar cell, first, a tunnel oxide layer, a first doped polysilicon layer, a laser light absorption layer, and a second doped polysilicon layer are formed on the entire surface of a silicon substrate in this order, and then, utilizing the function that the laser light absorption layer can strongly absorb the laser light of the set wavelength and vaporize it, the laser light absorption layer and the second doped polysilicon layer in the nonmetal contact region are removed with the laser light of the set wavelength to expose the nonmetal contact region on the surface of the first doped polysilicon layer, and finally, the solar cell in the above embodiment may be formed.

[0054] By removing the laser light absorption layer and the second doped polysilicon layer in the non-metal contact region with laser light without using a mask or chemical etching process, the process for manufacturing the selective passivation contact structure of the solar cell can be effectively simplified. By adding a laser light etching device, the process becomes compatible with the mass production process of conventional crystalline silicon solar cells, the process cost is low, it is easy to be widely used, and it can be mass-produced quickly, and the problems of complicated process and high cost in the current manufacturing method of the selective polysilicon thin film passivation contact structure can be effectively solved.

[0055] Optionally, the step of providing a silicon substrate may include cleaning the silicon substrate to remove contaminants on the surface of the silicon substrate to provide a clean, flat silicon substrate for use in a subsequent process.

[0056] Alternatively, the tunnel oxide layer on the surface of the silicon substrate may be formed by thermal oxidation, the process in which silicon oxidizes in air to form a native oxide layer is called thermal oxidation, which can provide a high-performance native silicon dioxide layer on the surface of silicon.

[0057] Alternatively, the first doped polysilicon layer may be formed by low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition (PECVD), which has good film quality.

[0058] Alternatively, the range of the set wavelength of the laser light may include 355 nm to 532 nm.

[0059] In some embodiments, the laser light includes an ultraviolet picosecond laser light, and the set wavelength includes 355 nm. By using the ultraviolet picosecond laser light of 355 nm, the thermal effect is small, the speed is high, and the processing accuracy is high.

[0060] In some embodiments, the laser power range may include 1 W to 10 W, which can prevent damage to the silicon substrate and conserve power.

[0061] In some embodiments, the method comprises: Step S700 includes forming a non-metal contact region on the surface of the first doped polysilicon layer and a passivation anti-reflective layer on the surface of the second doped polysilicon layer; The method further includes a step S800 of forming a metal electrode on the passivation anti-reflection layer in an area corresponding to the second doped polysilicon layer.

[0062] Alternatively, the passivation anti-reflective layer may be formed by chemical vapor deposition or atomic layer deposition (ALD). Atomic layer deposition is a method in which a material can be plated on the substrate surface as a monoatomic film, and the quality of the film formed is good.

[0063] Optionally, a metal electrode may be formed on the passivation anti-reflective layer in a screen printing process, the metal electrode being printed onto the second doped polysilicon layer remaining in the metal contact area.

[0064] The method for manufacturing a solar cell according to the present invention will be described in further detail below with reference to a specific example. providing a silicon substrate, the silicon substrate being a silicon wafer, comprising cleaning the silicon substrate; forming a tunnel oxide layer on a surface of a silicon substrate, the step including forming a silicon oxide layer having a thickness of 1.5 nm on the surface of a silicon wafer by a thermal oxygen method; forming a first doped polysilicon layer on a surface of the tunnel oxide layer, the first doped polysilicon layer including forming a phosphorus-doped or boron-doped polysilicon thin film having a thickness of 20 nm by low pressure chemical vapor deposition or chemical vapor deposition; forming a laser light absorption layer on the surface of the first doped polysilicon layer, the step including forming a titanium oxide thin film having a thickness of 3 nm by low pressure chemical vapor deposition or chemical vapor deposition; forming a second doped polysilicon layer on the surface of the laser light absorption layer, the second doped polysilicon layer including forming a phosphorus-doped or boron-doped polysilicon thin film having a thickness of 150 nm by low pressure chemical vapor deposition or chemical vapor deposition; a step of removing the laser light absorption layer and the second doped polysilicon layer in the non-metal contact region on the surface of the first doped polysilicon layer with a laser light of a set wavelength to expose the non-metal contact region on the surface of the first doped polysilicon layer, the step including scanning the second doped polysilicon thin film in the non-metal contact region with a picosecond laser light of a wavelength of 355 nm, and removing the laser light absorption layer and the second doped polysilicon thin film in the non-metal contact region by utilizing the titanium oxide thin film strongly absorbing the 355 nm laser light and vaporizing and evaporating due to the action of the laser light; forming a passivation anti-reflective layer, the passivation anti-reflective layer comprising depositing an aluminum oxide / silicon nitride stack or a silicon nitride stack by chemical vapor deposition or atomic deposition; and forming each metal electrode, the step including forming a metal electrode, which is a silver electrode or a silver aluminum electrode, on the surface of the passivation anti-reflective layer, which is printed on the remaining second doped polysilicon layer by a screen printing process.

[0065] The solar cell obtained by the solar cell manufacturing method of this embodiment can improve the photoelectric conversion efficiency of a crystalline silicon solar cell by 0.2%.

[0066] The photovoltaic assembly provided in one embodiment of the present application includes a solar cell provided according to any of the above-mentioned embodiments.

[0067] Since the photovoltaic assembly includes a solar cell provided by any of the above-mentioned embodiments, it has the same beneficial effects and will not be described here.

[0068] The technical features of the embodiments described above can be combined in any manner, and for the sake of brevity, not all possible combinations of the technical features in the embodiments described above have been described; however, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope described in this specification.

[0069] The above examples merely show some embodiments of the present application, and although the description is specific and detailed, it should not be understood as limiting the scope of the present invention. It should be noted that those skilled in the art can make some modifications and improvements that fall within the scope of the present application without departing from the idea of ​​the present application. Therefore, the scope of the patent of the present application shall be subject to the scope of the attached claims. [Explanation of symbols]

[0070] 100 solar cell; 1 silicon substrate; 2 tunnel oxide layer; 3 first doped polysilicon layer; 4 laser light absorption layer; 5 second doped polysilicon layer; 6 passivation anti-reflection layer; 7 metal electrode

Claims

1. A solar cell comprising: A silicon substrate; a tunnel oxide layer provided on a surface of the silicon substrate; a first doped polysilicon layer provided on a surface of the tunnel oxide layer, the surface of the first doped polysilicon layer including a metal contact region and a non-metal contact region; a laser light absorption layer provided in the metal contact region but not in the nonmetal contact region on the surface of the first doped polysilicon layer, the laser light absorption layer being capable of absorbing a laser light having a set wavelength and vaporizing it; a second doped polysilicon layer provided on a surface of the laser light absorption layer in the metal contact region and not in the non-metal contact region; a metal electrode fixedly connected to the second doped polysilicon layer.

2. the tunnel oxide layer comprises a silicon dioxide layer; and / or 2. The solar cell of claim 1, wherein the tunnel oxide layer has a thickness of less than 3 nm.

3. the laser light absorption layer comprises a titanium oxide layer or an aluminum oxide layer, and / or 2. The solar cell according to claim 1, wherein the thickness range of the laser light absorption layer includes 1 nm to 5 nm.

4. 2. The solar cell according to claim 1, wherein the thickness of the second doped polysilicon layer is greater than the thickness of the first doped polysilicon layer.

5. The first doped polysilicon layer includes a phosphorus-doped polysilicon thin film or a boron-doped polysilicon thin film; and / or 2. The solar cell of claim 1, wherein the thickness range of the first doped polysilicon layer includes 5 nm to 100 nm.

6. The second doped polysilicon layer includes a phosphorus-doped polysilicon thin film or a boron-doped polysilicon thin film; and / or 2. The solar cell of claim 1, wherein the thickness range of the second doped polysilicon layer includes 70 nm to 200 nm.

7. The solar cell further comprises a passivation anti-reflective layer; The solar cell according to any one of claims 1 to 6, characterized in that the passivation anti-reflection layer is provided on the non-metal contact region at the surface of the first doped polysilicon layer and on the surface of the second doped polysilicon layer.

8. The passivation anti-reflective layer comprises a silicon nitride layer or a stack of an aluminum oxide layer and a silicon nitride layer, and / or The solar cell of claim 7, wherein the thickness range of the passivation anti-reflection layer comprises 70 nm to 80 nm.

9. A method for producing the solar cell according to any one of claims 1 to 6, comprising the steps of: Providing a silicon substrate; forming a tunnel oxide layer on a surface of the silicon substrate; forming a first doped polysilicon layer on a surface of the tunnel oxide layer; forming a laser light absorption layer on a surface of the first doped polysilicon layer; forming a second doped polysilicon layer on a surface of the laser light absorption layer; removing the laser light absorption layer and the second doped polysilicon layer in a non-metal contact region on a surface of the first doped polysilicon layer with laser light of a set wavelength to expose the non-metal contact region on the surface of the first doped polysilicon layer, thereby obtaining the solar cell.

10. The laser light includes an ultraviolet picosecond laser light, and the set wavelength includes 355 nm. The method for producing a solar cell according to claim 9 .

11. forming a passivation anti-reflective layer on the non-metal contact region at the surface of the first doped polysilicon layer and on the surface of the second doped polysilicon layer; forming a metal electrode on the passivation anti-reflective layer in a region corresponding to the second doped polysilicon layer. The method for producing a solar cell according to claim 9 .

12. A photovoltaic assembly comprising a solar cell according to any one of claims 1 to 6.

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