Solar cell, preparation method thereof and photovoltaic module

Abstract

The invention relates to a solar cell and a preparation method thereof, and a photovoltaic module, and the preparation method of the solar cell comprises the steps: providing a substrate which comprises a first surface and a second surface which are oppositely disposed along the thickness direction of the substrate; forming a tunneling passivation layer on the first surface of the substrate; based on physical vapor deposition, a first doping layer and a second doping layer are formed at least on the side, away from the substrate, of the tunneling passivation layer in a laminated mode, the doping type of the first doping layer and the doping type of the second doping layer are both P types, doping elements of the first doping layer and the doping elements of the second doping layer are not completely the same, the first doping layer at least comprises gallium elements, and the second doping layer at least comprises gallium elements. The second doping layer at least comprises a boron element, the first doping layer and the second doping layer are both prepared by physical vapor deposition, the doping elements of the first doping layer and the second doping layer are not completely the same, the cost is low, and the passivation performance is good.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a solar cell and a preparation method thereof, and a photovoltaic module. Background Art

[0002] At present, solar cells, a new energy technology, are experiencing an unprecedented development trend. Among them, crystalline silicon solar cells have been dominating the photovoltaic industry with a market share of more than 90%. With such a huge volume and broad market prospects, crystalline silicon solar cells are also developing continuously.

[0003] However, in the process of forming a P-type doped polysilicon layer, solar cells in the related art are mainly prepared by chemical vapor deposition (for example, PECVD for in-situ doping, or LPCVD process for non-in-situ doping), solution method and other processes, and their preparation cost is too high and the passivation effect is poor. Summary of the invention

[0004] Based on this, it is necessary to provide a solar cell and a preparation method thereof, and a photovoltaic module with low cost and good passivation effect in order to solve the above technical problems.

[0005] In a first aspect, the present application provides a method for preparing a solar cell, comprising:

[0006] Providing a substrate, the substrate comprising a first surface and a second surface arranged opposite to each other along a thickness direction of the substrate;

[0007] forming a tunnel passivation layer on the first surface of the substrate;

[0008] Based on physical vapor deposition, a first doping layer and a second doping layer are stacked at least on a side of the tunneling passivation layer away from the substrate, wherein the doping types of the first doping layer and the second doping layer are both P-type, and the doping elements of the first doping layer and the second doping layer are not completely the same, the first doping layer at least includes gallium, and the second doping layer at least includes boron.

[0009] In one embodiment, the forming of the first doping layer and the second doping layer at least on a side of the tunnel passivation layer away from the substrate based on physical vapor deposition includes:

[0010] Providing a target unit; wherein the target unit comprises a gallium-doped mixed material target and a boron-doped mixed material target, and the gallium-doped mixed material target and the boron-doped mixed material target are arranged in a deposition order;

[0011] Forming a first doped amorphous silicon layer and a second doped amorphous silicon layer on a side of the tunnel passivation layer away from the substrate based on physical vapor deposition; wherein the first doped amorphous silicon layer includes at least gallium, and the second doped amorphous silicon layer includes at least boron;

[0012] An annealing process is performed to form the first doping layer and the second doping layer.

[0013] In one embodiment, the forming of the first doped amorphous silicon layer and the second doped amorphous silicon layer on the side of the tunnel passivation layer away from the substrate based on physical vapor deposition includes:

[0014] Based on the mixed gas and the target material unit, magnetron sputtering is used to form the first doped amorphous silicon layer and the second doped amorphous silicon layer on the tunnel passivation layer away from the substrate; wherein the mixed gas includes a sputtering gas and a doping gas.

[0015] In one embodiment, the doping gas includes a gallium source precursor and a boron source precursor.

[0016] In one embodiment, the gallium source precursor includes trimethylgallium, and the boron source precursor includes at least one of hexahydroboron and trimethyl borate.

[0017] In one embodiment, the doping gas further includes at least one of methane, carbon dioxide and ammonia.

[0018] In one embodiment, the doping gas includes the methane, the carbon dioxide and the ammonia; wherein the doping percentage of the methane is 10%-50%, the doping percentage of the ammonia is 0.5%-30%, and the doping percentage of the carbon dioxide is 0.1%-50%.

[0019] In one embodiment, the forming of the first doping layer and the second doping layer on the side of the tunnel passivation layer away from the substrate based on physical vapor deposition includes:

[0020] The first doped amorphous silicon layer and the second doped amorphous silicon layer are deposited on a side of the tunnel passivation layer away from the substrate by bombarding each of the mixed material targets in the target unit in the deposition order with a high energy electron beam.

[0021] In one embodiment, the target unit includes at least two of the gallium-doped mixed material targets and at least two of the boron-doped mixed material targets, wherein the gallium-doped mixed material targets are arranged adjacent to each other, and the boron-doped mixed material targets are arranged adjacent to each other.

[0022] In one embodiment, the number of the first doping layer and the number of the second doping layer are at least two, respectively, and the first doping layers and the second doping layers are alternately formed on a side of the tunneling passivation layer away from the substrate.

[0023] In one embodiment, the first doped layers and the second doped layers are alternately formed on a side of the tunnel passivation layer away from the substrate, comprising:

[0024] Providing at least two target material units; the target material units include a gallium-doped mixed material target and a boron-doped mixed material target, and the gallium-doped mixed material target and the boron-doped mixed material target are arranged in a deposition order;

[0025] For each of the target material units, in the thickness direction, a first doped amorphous silicon layer and a second doped amorphous silicon layer are formed on the target structure based on physical vapor deposition; wherein the target structure includes a tunnel passivation layer or each of the second doped amorphous silicon layers;

[0026] Annealing is performed to form alternately arranged first doped layers and second doped layers on a side of the tunnel passivation layer away from the substrate.

[0027] In one embodiment, before forming the first doped amorphous silicon layer, the method further includes:

[0028] Providing an initial target material, wherein the initial target material is disposed adjacent to the gallium-doped mixed material target material;

[0029] An interfacial amorphous silicon layer is formed on a side of the tunneling passivation layer away from the substrate based on the initial target; wherein the first doped amorphous silicon layer is located on a side of the interfacial amorphous silicon layer away from the tunneling passivation layer.

[0030] In one embodiment, the initial target material includes an intrinsic target material not doped with P-type elements or a mixed target material lightly doped with P-type elements.

[0031] In one embodiment, before forming the second doped amorphous silicon layer, the method further includes:

[0032] A first interface oxide layer is formed on a side of the first doped amorphous silicon layer away from the tunnel passivation layer; wherein the second doped amorphous silicon layer is formed on a side of the first interface oxide layer away from the first doped amorphous silicon layer.

[0033] In one embodiment, after forming the first doped amorphous silicon layer and the second doped amorphous silicon layer on the target structure based on physical vapor deposition in the thickness direction for each of the target material units, the method further comprises:

[0034] A second interface oxide layer is formed on a side of the second gallium-doped amorphous silicon layer away from the first gallium-doped amorphous silicon layer.

[0035] In one embodiment, the physical vapor deposition also includes one of vacuum evaporation and arc plasma plating.

[0036] In a second aspect, the present application provides a solar cell, comprising:

[0037] A substrate, comprising a first surface and a second surface arranged opposite to each other along a thickness direction of the substrate;

[0038] A tunnel passivation layer, located on the first surface of the substrate;

[0039] A first doped layer, located on a side of the tunnel passivation layer away from the substrate;

[0040] a second doped layer, located on a side of the first doped layer away from the tunnel passivation layer;

[0041] The doping types of the first doping layer and the second doping layer are both P-type, and the doping elements of the first doping layer and the second doping layer are not completely the same, the first doping layer at least includes gallium, and the second doping layer at least includes boron;

[0042] At least one electrode, one of the electrodes is in contact with the second doped layer.

[0043] In one embodiment, the doping element of the first doping layer includes gallium;

[0044] The doping element of the second doping layer includes boron, or the doping element of the second doping layer includes boron and gallium.

[0045] In one of the embodiments, the solar cell includes at least two first doped layers and at least two second doped layers, wherein in the thickness direction, each of the first doped layers and each of the second doped layers are alternately located on a side of the tunneling passivation layer away from the substrate.

[0046] In one of the embodiments, in a direction from the substrate to the tunnel passivation layer, the concentration of the gallium element in each of the first doping layers gradually decreases.

[0047] In one embodiment, the maximum concentration range of gallium element in each of the first doping layers is 8E19 cm-3-12E19 / cm-3.

[0048] In one of the embodiments, in a direction from the substrate to the tunnel passivation layer, the concentration of the boron element in each of the second doping layers gradually decreases.

[0049] In one embodiment, the maximum concentration range of the boron element in each of the second doping layers is 5E19 cm-3-11E19 / cm-3.

[0050] In one embodiment, the thickness of the first doping layer is in the range of 10 nm to 150 nm, and the thickness of the second doping layer is in the range of 5 nm to 150 nm.

[0051] In one embodiment, the solar cell further comprises:

[0052] A first interface oxide layer, in the thickness direction, the first interface oxide layer is located between the first doping layer and the second doping layer.

[0053] In one embodiment, the solar cell further comprises:

[0054] A second interface oxide layer, in the thickness direction, the second interface oxide layer is located on a side of the second doping layer away from the first doping layer.

[0055] In one embodiment, the solar cell further comprises:

[0056] The interface polysilicon layer is located on a side of the tunnel passivation layer away from the substrate in the thickness direction; wherein the first doped layer is located on a side of the interface polysilicon layer away from the tunnel passivation layer.

[0057] In one embodiment, the first doping layer and the second doping layer are both prepared by physical vapor deposition.

[0058] In one embodiment, the physical vapor deposition includes one of vacuum evaporation, magnetron sputtering, reactive plasma plating and arc plasma plating.

[0059] In one embodiment, the first surface is a backlight surface; wherein the solar cell further comprises:

[0060] A first passivation anti-reflection layer is located on a side of the second doped layer away from the first doped layer;

[0061] A first polysilicon conductive layer, a second passivation anti-reflection layer, a second polysilicon conductive layer and a conductive passivation layer are stacked on the second surface of the substrate; wherein the doping types of the first polysilicon conductive layer and the second polysilicon conductive layer are both N-type;

[0062] A first electrode and a second electrode; wherein the first electrode is disposed on one side of the second surface of the substrate and contacts the conductive passivation layer, and the second electrode is disposed on one side of the first surface of the substrate and contacts the second doping layer.

[0063] In one embodiment, the first surface is a backlight surface, and the second surface includes a first area and a second area; wherein the solar cell further includes:

[0064] At least one third polysilicon conductive layer, stacked in the first region;

[0065] At least one third passivation anti-reflection layer, stacked in the second region;

[0066] At least one fourth passivation anti-reflection layer, stacked on a side of the second doped layer away from the first doped layer;

[0067] A first electrode and a second electrode; wherein the first electrode is disposed on one side of the second surface of the substrate and contacts the third polysilicon conductive layer, and the second electrode is disposed on one side of the first surface of the substrate and contacts the second doped layer.

[0068] In one embodiment, the first surface is a light-receiving surface, the first surface includes a first region and a second region, wherein the tunneling passivation layer is located in the first region of the first surface; wherein the solar cell further includes:

[0069] A tunneling oxide layer, a third doping layer and a fifth passivation subtractive layer are stacked on the second surface of the substrate, wherein the doping type of the third doping layer is different from the doping type of the first doping layer;

[0070] a sixth passivation anti-reflection layer, located on a side of the second doped layer away from the first doped layer and located in a second region of the first surface;

[0071] A first electrode and a second electrode; wherein the first electrode is disposed on one side of the first surface of the substrate and contacts the second doped layer, and the second electrode is disposed on one side of the second surface of the substrate and contacts the third doped layer.

[0072] In a third aspect, the present application provides a photovoltaic module, including at least one cell string, wherein the cell string includes at least two of the aforementioned solar cells, or solar cells manufactured by the aforementioned solar cell manufacturing method.

[0073] The solar cell and its preparation method, photovoltaic module, can be based on physical vapor deposition, and a first doping layer and a second doping layer can be stacked on the side of the tunnel passivation layer away from the substrate; wherein the doping type of the first doping layer and the second doping layer are both P-type, the first doping layer includes at least gallium, and the second doping layer includes at least boron, which can be used to achieve interface passivation of the tunnel passivation layer, play a field effect passivation effect, and can generate an electric field at the interface to prevent carriers of similar polarity from approaching by the same-order repulsion effect, thereby greatly reducing the recombination of photogenerated carriers. Specifically, due to the low interface segregation coefficient of the boron element at the tunnel passivation layer (for example, SiOx), the passivation performance between p+poly-Si (doped polysilicon and tunnel passivation layer) will be reduced. At the same time, since the solid solubility of the gallium element Ga in silicon is one order of magnitude lower than that of the boron element, the effective doping concentration activated by annealing is low, and it is difficult to obtain a low contact resistivity. By arranging the gallium-doped first doping layer adjacent to the tunnel passivation layer, the boron-doped second doping layer can be prevented from being arranged in contact with the tunnel passivation layer, thereby improving the passivation performance and reducing the contact resistivity.

[0074] In addition, the first doping layer and the second doping layer can be formed by physical vapor deposition, which can significantly reduce the process cost compared to ion implantation, solution method and other processes in related technologies, and improve the passivation effect of the P-type passivation stack, reduce the contact resistivity, and thus improve the efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0076] Figure 1 A schematic diagram of the structure of a solar cell provided in an embodiment of the present application;

[0077] Figure 2 A schematic diagram of another structure of a solar cell provided in an embodiment of the present application;

[0078] Figure 3 A schematic diagram of another structure of a solar cell provided in an embodiment of the present application;

[0079] Figure 4 A partial schematic diagram of a solar cell in one embodiment of the present application;

[0080] Figure 5 A partial schematic diagram of a solar cell in another embodiment of the present application;

[0081] Figure 6 A partial schematic diagram of a solar cell in another embodiment of the present application;

[0082] Figure 7 is a flow chart of a method for preparing a solar cell in one embodiment of the present application;

[0083] Figure 8 This is a flow chart of forming a first doping layer and a second doping layer at least on a side of the tunnel passivation layer away from the substrate based on physical vapor deposition in an embodiment of the present application;

[0084] Fig. 9 This is an arrangement diagram of multiple targets in one embodiment of the present application;

[0085] Fig.10 This is an arrangement diagram of multiple targets in another embodiment of the present application;

[0086] Fig.11 It is a cross-sectional view of a process of forming a first doping layer and a second doping layer at least on a side of the tunnel passivation layer away from the substrate based on physical vapor deposition in an embodiment of the present application;

[0087] Fig.12 It is a cross-sectional view of a process of forming a first doping layer and a second doping layer at least on a side of the tunnel passivation layer away from the substrate based on physical vapor deposition in another embodiment of the present application;

[0088] Fig.13 It is a cross-sectional view of a process of forming a first interface oxide layer on a side of the first doped amorphous silicon layer away from the tunnel passivation layer in another embodiment of the present application;

[0089] Fig.14 It is a schematic diagram of the structure of a photovoltaic module in one embodiment of the present application.

[0090] Description of reference numerals:

[0091] 100-Solar cell;

[0092] 110 - substrate; 120 - tunnel passivation layer; 131 - first doping layer; 132 - second doping layer;

[0093] 101-gallium-doped mixed material target; 102-boron-doped mixed material target; 103-initial target;

[0094] 1301-first doped amorphous silicon layer; 1302-second doped amorphous silicon layer; 1303-interface amorphous silicon layer;

[0095] 140-first interface oxide layer; 150-second interface oxide layer; 160-interface polysilicon layer;

[0096] 181 - first passivation anti-reflection layer; 171 - first polysilicon conductive layer; 182 - second passivation anti-reflection layer; 172 - second polysilicon conductive layer; 183 - conductive passivation layer;

[0097] 173 - a third polysilicon conductive layer; 184 - a third passivation anti-reflection layer; 185 - a fourth passivation anti-reflection layer;

[0098] 122 - tunneling oxide layer; 133 - third doping layer; 186 - fifth passivation subtraction layer; 187 - sixth passivation anti-reflection layer;

[0099] F1-first area; F2-second area; F3-third area; F4-fourth area;

[0100] 191 - first electrode; 192 - second electrode;

[0101] 200-photovoltaic module; 210-battery string. DETAILED DESCRIPTION

[0102] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0103] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0104] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0105] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0106] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0107] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0108] The solar cell and its manufacturing method and photovoltaic module of the embodiment of the present application are described below with reference to the accompanying drawings.

[0109] The solar cell provided in the embodiment of the present application may be any one of TOPCon, BC, POLO, TOPCore and the like solar cells. Figure 1 A schematic diagram of the structure of a solar cell provided in an embodiment of the present application. Figure 2 A schematic diagram of another structure of a solar cell provided in an embodiment of the present application. Figure 3 A schematic diagram of another structure of a solar cell provided in an embodiment of the present application.

[0110] refer to Figure 1-Figure 3 In one embodiment of the present application, the solar cell may include a substrate 110 , a tunnel passivation layer 120 , a first doping layer 131 , a second doping layer 132 and at least one electrode 191 or 192 .

[0111] The substrate 110 includes a first surface and a second surface arranged opposite to each other along the thickness direction of the substrate 110. One of the first surface and the second surface is a light-receiving surface, and the other of the first surface and the second surface is a backlight surface. It can be understood that in the thickness direction of the substrate 110, there are opposite backlight surfaces and light-receiving surfaces. The light-receiving surface can be understood as the surface of the solar cell facing the sunlight, and the backlight surface can be understood as the surface of the solar cell facing away from the sunlight. The substrate 110 is used to receive incident light and generate photogenerated carriers. The substrate 110 includes but is not limited to a doped semiconductor substrate made of silicon or germanium, or a doped compound semiconductor substrate of silicon carbide, silicon germanium, gallium arsenide, indium phosphide, zinc oxide or gallium oxide. Exemplarily, in the embodiment of the present application, the material of the substrate 110 can be a doped single crystal silicon material. Further, the doping element type of the substrate 110 can be N-type, and the N-type element can be, for example, any one of phosphorus, arsenic or antimony; the doping element type of the substrate 110 can also be P-type, and the P-type element can be, for example, boron and gallium. Exemplarily, the doping element type of the substrate 110 is N-type. In the implementation of the present application, the light-receiving surface and the backlight surface of the substrate 110 may also have certain morphological changes based on the morphology of the battery film layer and other features.

[0112] The tunneling passivation layer 120, the first doping layer 131 and the second doping layer 132 are stacked on the first surface of the substrate 110. It is understood that the tunneling passivation layer 120 may be located on the backlight side of the substrate or on the light-receiving side of the substrate. The tunneling passivation layer 120 may be located on a part or the entire surface of the first surface of the substrate. The material of the tunneling passivation layer 120 may be a tunneling oxide material, such as silicon oxide, silicon oxynitride, aluminum oxide, titanium oxide, or silicon oxide doped with N-type elements. Optionally, the material of the tunneling passivation layer 120 may also include at least one of magnesium fluoride, amorphous silicon, polycrystalline silicon, silicon carbide, and silicon nitride. Exemplarily, the material of the tunneling passivation layer 120 includes SiOx. In an exemplary embodiment, the thickness of the tunneling passivation layer 120 ranges from 0.5nm to 3nm. The tunneling passivation layer 120 is used to achieve interface passivation of the substrate 110, which has a chemical passivation effect. Specifically, by saturating the dangling bonds on the surface of the substrate 110 , the interface defect state density of the substrate 110 is reduced, thereby reducing the recombination centers of the substrate 110 to reduce the carrier recombination rate, thereby increasing the open circuit voltage of the solar cell and improving the photoelectric conversion efficiency of the solar cell.

[0113] The first doping layer 131 is located between the tunnel passivation layer 120 and the second doping layer 132. It can be understood that the first doping layer 131 can be located on the side surface of the tunnel passivation layer 120 away from the substrate. The materials of the first doping layer 131 and the second doping layer 132 can respectively include doped polysilicon, or doped polysilicon containing at least one element of oxygen, carbon, and nitrogen. In addition, the doping types of the first doping layer 131 and the second doping layer 132 are both P-type. In the embodiment of the present application, the doping elements of the first doping layer 131 and the second doping layer 132 are not exactly the same. The first doping layer includes at least gallium, and the second doping layer includes at least boron. For example, the first doping layer 131 and the second doping layer 132 can respectively include main doping elements. Optionally, the second doping layer 132 can also include auxiliary doping elements. Among them, the main doping elements of the first doping layer 131 and the second doping layer 132 are different. Exemplarily, the main doping element of the first doping layer 131 is gallium, and the main doping element of the second doping layer 132 is boron. Optionally, the auxiliary doping element of the second doping layer 132 may be the same as the main doping element of the first doping layer 131 .

[0114] In the embodiment of the present application, the solar cell includes a substrate, a tunnel passivation layer, a first doping layer 131 and a second doping layer 132, which can be used to realize the interface passivation of the tunnel passivation layer, play the effect of field effect passivation, and can generate an electric field at the interface to prevent carriers of similar polarity from approaching by the same-level repulsion effect, thereby greatly reducing the recombination of photogenerated carriers. The first doping layer 131 is a polycrystalline silicon layer mainly doped with gallium, and the second doping layer 132 is a polycrystalline silicon layer mainly doped with boron. Since the boron element has a low interface segregation coefficient at the tunnel passivation layer (for example, SiOx), the passivation performance between p+poly-Si (doped polycrystalline silicon and tunnel passivation layer) will be reduced. At the same time, since the solid solubility of gallium Ga in silicon is one order of magnitude lower than that of boron, the effective doping concentration activated by annealing is low, and it is difficult to obtain a low contact resistivity. By arranging the first doping layer 131 doped with gallium adjacent to the tunnel passivation layer 120, the second doping layer 132 doped with boron can be avoided from being arranged in contact with the tunnel passivation layer, and the passivation performance can be improved. In addition, the size of the gallium element is larger than that of the boron element, and the size of the gallium element is close to that of the phosphorus P element. A similar internal expansion effect can be achieved at the same annealing temperature, thereby ensuring the solid solubility of the gallium element in silicon. This can not only further improve the passivation effect between the first doped layer 131 and the tunnel passivation layer, but also reduce the contact resistivity.

[0115] In addition, in the embodiment of the present application, the first doping layer 131 and the second doping layer 132 are both prepared by physical vapor deposition (PVD) technology. Exemplarily, the physical vapor deposition may include vacuum evaporation (for example, thermal evaporation such as resistance heating, high-frequency induction heating, and electron beam, laser beam and ion beam evaporation, etc.), magnetron sputtering, reactive plasma plating (RPD), arc plasma plating. It should be noted that the physical vapor deposition used for the first doped polysilicon and the second doped polysilicon is the same. Exemplarily, the first doping layer 131 and the second doping layer 132 can be continuously formed by physical vapor deposition. In this way, the first doping layer 131 and the second doping layer 132 can be formed by using the same physical vapor deposition. Compared with the related art using ion implantation, solution method and other processes to prepare a single-layer doping layer, it is also impossible to form a laminated passivation film layer including the first doping layer and the second doping layer. The solar cell provided by the embodiment of the present application can greatly reduce the process cost.

[0116] In an exemplary embodiment, the doping element of the first doping layer 131 is gallium, and the doping element of the second doping layer 132 is boron.

[0117] Optionally, the doping element of the first doping layer 131 may include boron and gallium, wherein gallium is the main doping element. For example, the doping concentration of gallium is higher than that of boron.

[0118] Optionally, the doping elements of the second doping layer 132 may include boron and gallium, wherein boron is the main doping element. For example, the doping concentration of boron is higher than that of gallium.

[0119] In this embodiment, the second doping layer 132 is doped with boron and boron at the same time, which can not only reduce the influence of light attenuation on the performance of polysilicon, but also make the resistance range of the second doping layer 132 narrower and more uniform.

[0120] Figure 4 FIG. 1 is a partial schematic diagram of a solar cell in an embodiment of the present application. In an exemplary embodiment, please continue to refer to Figure 4 The solar cell includes at least two first doping layers 131 and at least two second doping layers 132, wherein in the thickness direction (or the first direction), each first doping layer 131 and each second doping layer 132 are alternately located on the side of the tunnel passivation layer 120 away from the substrate. The first direction is the direction from the substrate to the first doping layer.

[0121] In the embodiment of the present application, for the convenience of description, a solar cell is described as including three first doping layers 131 and three second doping layers 132. Among them, the first doping layer 131-1, the second doping layer 132-1, the first doping layer 131-2, the second doping layer 132-2, the first doping layer 131-3, and the second doping layer 132-3 are stacked and located on a part or the entire surface of the first surface of the substrate.

[0122] In the second direction, the concentration of gallium in each first doping layer 131 gradually decreases. It can be understood that the doping element gallium in each first doping layer 131 diffuses along the second direction. The second direction is opposite to the first direction, and the second direction can be a direction from the second doping layer 132 to the tunnel passivation layer 120.

[0123] In an exemplary embodiment, the maximum concentration range of the gallium element in each first doping layer 131 is 8E19cm -3 -12E19 / cm -3 For example, at the interface of the tunnel passivation layer 120 (eg, SiOx), the concentration of the doped gallium element in the first doping layer 131 is about 1-5E19cm -3 .

[0124] In the second direction, the concentration of the boron element in each second doping layer 132 gradually decreases. It can be understood that the doping element boron in each second doping layer 132 diffuses along the second direction. In an exemplary embodiment, the maximum concentration range of the boron element in each second doping layer 132 is 5E19cm -3 -11E19 / cm -3 Since too high a doping concentration of boron will destroy the passivation effect of the ultra-thin tunnel passivation layer 120, in the embodiment of the present application, the doping concentration of boron in the first P-type passivation stack 130 is lower than 1E17cm -3 In this way, the boron element of the second doping layer 132 can be prevented from diffusing into the SiOx interface of the tunneling passivation layer 120, so as to avoid destroying the passivation effect of the tunneling passivation layer 120.

[0125] In an exemplary embodiment, the thickness of the first doping layer 131 ranges from 10nm to 150nm. For example, the thickness of the first doping layer 131 can be 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm or 150nm. The thickness of the second doping layer 132 ranges from 5nm to 150nm. For example, the thickness of the second doping layer 132 can be 5nm, 8nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm or 150nm. In this way, it is beneficial to make the P-type passivation stack 130 have a more excellent passivation performance.

[0126] In this embodiment, the solar cell includes a plurality of first doping layers 131 and a plurality of second doping layers 132 alternately located on the tunnel passivation layer 120. The doping concentration of gallium in the first doping layer 131 gradually increases in the first direction; the doping concentration of boron in the second doping layer 132 also gradually increases in the first direction, so that the doping elements in the first doping layer 131 and the second doping layer 132 closest to the tunnel passivation layer 120 have the lowest doping concentration. The low doping concentration can reduce the interface state density with the tunnel passivation layer 120 and have a lower band gap, which can increase or decrease the contact and passivation effects, and can also improve the transmission of carriers, thereby improving the photoelectric conversion efficiency of the solar cell.

[0127] In an exemplary embodiment, please continue to refer to Figure 1-Figure 3 , the solar cell further includes: at least one first interface oxide layer 140. The first interface oxide layer 140 is located between the first doping layer 131 and the second doping layer 132. In the embodiment of the present application, a first doping layer 131 and a second doping layer 132 are collectively understood as a P-type passivation structure unit. Among them, the number of first interface oxide layers 140 is less than or equal to the number of P-type passivation structure units. For example, the solar cell includes m P-type passivation structure units, wherein a first interface oxide layer 140 is provided between the first doping layer 131 and the second doping layer 132 of each P-type passivation structure unit. Optionally, a first interface oxide layer 140 is provided between the first doping layer 131 and the second doping layer 132 in the bottommost P-type passivation structure unit of the m P-type passivation structure units (that is, the P-type passivation structure unit closest to the tunnel passivation layer 120), and the first interface oxide layer 140 is not provided in other P-type passivation structure units. Optionally, among the m P-type passivation structure units, some of the P-type passivation structure units are provided with the first interface oxide layer 140 , and some of the P-type passivation structure units are not provided with the first interface oxide layer 140 .

[0128] The material of the first interface oxide layer 140 may be a dielectric material, such as at least one of silicon oxide, magnesium fluoride, silicon oxide, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide or titanium oxide. In the embodiment of the present application, the material of the first interface oxide layer 140 may be silicon oxide. Generally speaking, the boron element in the second doping layer 132 may diffuse toward the tunnel passivation layer 120 along the second direction. After passing through the first interface oxide layer 140, the doping concentration of the boron element is reduced by 2-4E19cm -3 As can be seen from the above analysis, the doping concentration of the boron element can be reasonably set so that the doping concentration of the boron element at the interface between the tunnel passivation layer 120 and the first doping layer 131 is lower than 1E17 cm -3 , which can prevent excessively high concentration of B element from destroying the passivation effect of the ultra-thin tunneling passivation layer 120.

[0129] In an exemplary embodiment, the thickness of the first interface oxide layer 140 is 0.5 nm-2 nm. For example, the thickness of the first interface oxide layer 140 may be 0.5 nm, 0.8 nm, 1 nm, 1.5 nm, 1.8 nm, or 2 nm.

[0130] By setting a first interface oxide layer 140 between the first doping layer 131 and the second doping layer 132, the diffusion rate of the boron element can be alleviated to avoid excessive concentration of B element destroying the passivation effect of the ultra-thin tunneling passivation layer 120, and the passivation performance between the first doping layer 131 and the second doping layer 132 can also be improved.

[0131] Figure 5 FIG. 1 is a partial schematic diagram of a solar cell in another embodiment. In an exemplary embodiment, Figure 5 As shown, the solar cell may also include: at least one second interface oxide layer 150. Wherein, in the thickness direction, the second interface oxide layer is located on the side of the second doped layer away from the first doped layer. It can be understood that each second interface oxide layer 150 is located between two adjacent P-type passivation structure units. The material of the second interface oxide layer 150 may include but is not limited to at least one of silicon oxide, magnesium fluoride, silicon oxide, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide or titanium oxide. In an embodiment of the present application, the material of the second interface oxide layer 150 may be silicon oxide. The thickness of the second interface oxide layer 150 is 0.5nm-2nm. For example, the thickness of the second interface oxide layer 150 may be 0.5nm, 0.7nm, 1nm, 1.2nm, 1.5nm, 1.8nm or 2nm.

[0132] In this embodiment, by disposing a second interface oxide layer 150 between two P-type passivation structural units, the solar cell can have a more excellent passivation performance.

[0133] Figure 6 FIG. 1 is a partial schematic diagram of a solar cell in another embodiment. In an exemplary embodiment, Figure 6 As shown, the solar cell further includes an interface polysilicon layer 160 located between the tunnel passivation layer 120 and the first doping layer 131. The material of the interface polysilicon layer 160 may be polysilicon. Optionally, the doping element of the interface polysilicon layer 160 includes at least one of oxygen, carbon and nitrogen. The thickness of the interface polysilicon layer 160 is 3 nanometers to 150 nanometers.

[0134] Please continue to refer to Figure 1 In this embodiment, the first surface is the backlight surface, and the second surface is the light-receiving surface, wherein the tunnel passivation layer 120, the first doping layer 131, and the second doping layer 132 in the above-mentioned embodiment are located on the side where the backlight surface is located. Further, the solar cell further includes: a first passivation anti-reflection layer 181, a first polysilicon conductive layer 171, a second passivation anti-reflection layer 182, a second polysilicon conductive layer 172, a conductive passivation layer 183, a first electrode 191, and a second electrode 192. Among them, the first passivation anti-reflection layer 181 is located on the side of the second doping layer 132 away from the first doping layer 131. The first polysilicon conductive layer 171, the second passivation anti-reflection layer 182, the second polysilicon conductive layer 172, and the conductive passivation layer 183 are stacked and located on the second surface of the substrate 110. Among them, the doping types of the first polysilicon conductive layer 182 and the second polysilicon conductive layer 283 are both N-type. The first electrode 191 is disposed on one side of the second surface of the substrate and contacts the conductive passivation layer 183 . The second electrode 192 is disposed on one side of the first surface of the substrate 110 and contacts the second doping layer 132 .

[0135] Please continue to refer to Figure 2 In this embodiment, the first surface is the backlight surface, and the second surface is the light-receiving surface. The tunneling passivation layer 120, the first doping layer 131, and the second doping layer 132 in the aforementioned embodiment are located on the side where the backlight surface is located. Furthermore, the solar cell also includes: at least one third polysilicon conductive layer 173, at least one third passivation anti-reflection layer 184, at least one fourth passivation anti-reflection layer 185, and a first electrode 191 and a second electrode 191. The second surface of the substrate 110 includes a first region F1 and a second region F2, and the first region F1 is arranged corresponding to the first electrode 191, for example, an electrode region; the second region F2 can be understood as a non-electrode region.

[0136] At least one third polysilicon conductive layer 173 is stacked in the first region F1. Exemplarily, in the embodiment of the present application, the doping element of the third polysilicon conductive layer 173 is phosphorus element P, or other N-type elements. The number of the third polysilicon conductive layer 173 can be one layer, or can be a plurality of layers greater than or equal to 2. The material or doping material of each third polysilicon conductive layer 173 can be the same or different.

[0137] At least one third passivation anti-reflection layer 184 is stacked in the second region F2. For example, the number of the third passivation anti-reflection layer can be one layer or multiple layers greater than or equal to 2. The materials of each third passivation anti-reflection layer can be the same or different.

[0138] At least one fourth passivation anti-reflection layer 185 is stacked on a side of the second doping layer 132 away from the first doping layer 131. Exemplarily, the number of the fourth passivation anti-reflection layer 185 can be one layer, or a plurality of layers greater than or equal to 2. The materials of each fourth passivation anti-reflection layer 185 can be the same or different.

[0139] The first electrode 191 is disposed on the second surface side of the substrate 110 and contacts the third polysilicon conductive layer 173 . The second electrode 192 is disposed on the first surface side of the substrate and contacts the second doping layer 132 .

[0140] Please continue to refer to Figure 3 In this embodiment, the first surface is the light-receiving surface, and the second surface is the backlight surface. The tunnel passivation layer 120, the first doping layer 131, and the second doping layer 132 in the above-mentioned embodiment are located on the side where the light-receiving surface is located. Furthermore, the solar cell may also include: a tunnel oxide layer 122, a third doping layer 133, a fifth passivation subtraction layer 186, a sixth passivation anti-reflection layer 187, a first electrode 191, and a second electrode 192.

[0141] In the embodiment of the present application, the first surface of the substrate 110 includes a third region F3 and a fourth region F4. The tunneling passivation layer 122 is located in a part of the first surface, for example, the tunneling passivation layer 122 may be located in the third region F3 of the first surface. The sixth passivation anti-reflection layer 187 is located on the side of the second doping layer 132 away from the first doping layer 131 and in the fourth region F4 of the first surface. The tunneling oxide layer 122, the third doping layer 133 and the fifth passivation subtractive layer 186 are stacked on the second surface of the substrate 110. The doping type of the third doping layer 133 is different from the doping type of the first doping layer 131, for example, the doping type of the third doping layer 133 is N-type, for example, it may be a phosphorus-doped polysilicon layer. The first electrode 191 is provided on one side of the first surface of the substrate 110 and contacts the second doping layer 132, and the second electrode 192 is provided on one side of the second surface of the substrate 110 and contacts the third doping layer 133.

[0142] It should be noted that the solar cell provided in the embodiment of the present application is not limited to the aforementioned Figure 1-Figure 3 The solar cell shown may also be a solar cell of other structural types.

[0143] Figure 7 Schematic diagram of a process for manufacturing a solar cell provided in an embodiment of the present application. This embodiment provides a method for manufacturing a solar cell, which is used to manufacture the solar cell in any of the above embodiments. The structure, function, working principle, etc. of the solar cell have been described in detail in the first embodiment, and will not be repeated here. This embodiment of the present application also provides a method for manufacturing a solar cell. Figure 7 As shown, the method for preparing a solar cell includes steps 702 to 706.

[0144] Step 702: Provide a substrate, wherein the substrate includes a first surface and a second surface that are oppositely disposed along a thickness direction of the substrate.

[0145] Please continue to refer to Figure 1-3 In the embodiment of the present application, the substrate 110 is an N-type silicon substrate as an example for explanation. After providing the N-type silicon substrate, the surface cutting damage layer can be removed by an alkali polishing process, and the N-type silicon substrate can be pre-cleaned to remove impurities on the surface of the N-type silicon substrate. Optionally, the method for preparing a solar cell provided in the embodiment of the present application also includes texturing a portion of the surface of the substrate 110 to form a textured surface. In addition, a cleaning solution (for example, RCA-1 and RCA-2) can be used to clean the organic matter and metal ions on the textured surface, which can reduce the reflectivity and increase the absorption of sunlight by the silicon substrate 110.

[0146] Step 704: forming a tunnel passivation layer on the first surface of the substrate.

[0147] For example, a plasma enhanced chemical vapor deposition (PECVD) method can be used to form a tunnel passivation layer 120 on one side of the substrate 110. For example, a substrate (e.g., a silicon wafer) can be placed in a plate-type PECVD device to deposit tunnel SiOx, and N20 and Ar can be used as reaction gases to form the tunnel passivation layer 120 at a temperature of 400-500°C.

[0148] Step 706 , based on physical vapor deposition, stacking a first doping layer and a second doping layer at least on a side of the tunnel passivation layer away from the substrate.

[0149] Physical vapor deposition refers to the use of low voltage, high current arc discharge technology under vacuum conditions, using gas discharge to evaporate the target material and ionize both the evaporated material and the gas, and using the acceleration of the electric field to deposit the evaporated material and its reaction products on the tunnel passivation layer 120. In the implementation of the present application, physical vapor deposition includes but is not limited to vacuum evaporation (for example, thermal evaporation such as resistance heating, high frequency induction heating, and electron beam, laser beam and ion beam evaporation, etc.), magnetron sputtering, reactive plasma plating (RPD), arc plasma plating, etc. In the embodiment of the present application, the doping element type of the first doping layer 131 and the second doping layer 132 are both P-type, but the main doping elements of the first doping layer 131 and the second doping layer 132 are different. Exemplarily, the main doping element of the first doping layer 131 is gallium, and the main doping element of the second doping layer 132 is boron.

[0150] In an embodiment of the present application, the preparation method of the solar cell may include providing a substrate, forming a tunneling passivation layer on one side of the substrate, forming at least one passivation stack on the side of the tunneling passivation layer away from the substrate based on physical vapor deposition, and forming a first doping layer and a second doping layer on at least the side of the tunneling passivation layer away from the substrate based on physical vapor deposition. In this way, the first doping layer and the second doping layer can be continuously formed by physical vapor deposition. Compared with the related art that uses ion implantation, solution method and other processes to prepare a single doping layer, it is also impossible to form a stacked passivation film layer including the first doping layer and the second doping layer. The physical vapor deposition technology provided in the embodiment of the present application is closer to mass production conditions, which can realize a large area, high production capacity, stable and controllable process, can simplify the process steps of forming the first doping layer and the second doping layer, and greatly reduce the process cost.

[0151] In addition, the first doped layer 131 is a polysilicon layer mainly doped with gallium, and the second doped layer 132 is a polysilicon layer mainly doped with boron. Since the boron element has a low interface segregation coefficient at the tunnel passivation layer (e.g., SiOx), the passivation performance between p+poly-Si (doped polysilicon and tunnel passivation layer) will be reduced. At the same time, since the solid solubility of gallium Ga in silicon is one order of magnitude lower than that of boron, the effective doping concentration activated by annealing is low, and it is difficult to obtain a low contact resistivity. By arranging the first doped gallium layer 131 adjacent to the tunnel passivation layer 120, the second doped boron layer 132 can be avoided from being arranged in contact with the tunnel passivation layer, and the passivation performance can be improved. In addition, the size of the gallium element is larger than that of the boron element, and the size of the gallium element is close to that of the phosphorus P element. At the same annealing temperature, a similar internal expansion effect can be achieved, which ensures the solid solubility of the gallium element in silicon, which can not only further improve the passivation effect between the first doped layer 131 and the tunnel passivation layer, but also reduce the contact resistivity.

[0152] In an exemplary embodiment, Figure 8 As shown, based on physical vapor deposition, a first doping layer and a second doping layer are formed at least on a side of the tunnel passivation layer away from the substrate, including steps 802 to 806.

[0153] Step 802, providing a target unit.

[0154] The target unit includes a gallium-doped mixed material target and a boron-doped mixed material target, and the gallium-doped mixed material target and the boron-doped mixed material target are arranged in a deposition order. The gallium-doped mixed material target may be a target including a mixed material, and the mixed material may include silicon and gallium elements, which is a gallium-doped silicon-based target. The boron-doped mixed material target may be a target including a mixed material, and the mixed material may include silicon and boron elements, which is a boron-doped silicon-based target.

[0155] Fig. 9 and Fig.10 are respectively the arrangement diagrams of the respective mixed material targets. The formation of the mixed material targets may include but is not limited to rectangular, circular, elliptical, etc. Among them, the number of gallium-doped mixed material targets 101 and boron-doped mixed material targets 102 may be 1 or more. It should be noted that the shape and number of the mixed targets are not specifically limited in the embodiments of the present application.

[0156] Each gallium-doped mixed material target 101 and each boron-doped mixed material target 102 are arranged in a deposition order. The deposition order may be the deposition order of each doping layer during the formation of the first doping layer and the second doping layer. For example, in the embodiment of the present application, the amorphous silicon film layer corresponding to the first doping layer 131 is formed earlier than the amorphous silicon film layer corresponding to the second doping layer 132.

[0157] For illustration purposes, please refer to Fig. 9 , taking two gallium-doped mixed material targets 101 and two boron-doped mixed material targets 102 as examples for explanation. Among them, two gallium-doped mixed material targets 101 are arranged continuously to form a first doped layer 131; two boron-doped mixed material targets 102 are arranged continuously to form a second doped layer 132. Two gallium-doped mixed material targets 101 and two boron-doped mixed material targets 102 are arranged along a third direction. The third direction can be understood as the order in which the targets are bombarded during physical vapor deposition. It can be understood that two gallium-doped mixed material targets 101 and two boron-doped mixed material targets 102 are a target unit. In an embodiment of the present application, at least one target unit may be provided, and each target unit may include at least one gallium-doped mixed material target 101 and at least one boron-doped mixed material target 102, respectively.

[0158] Optionally, the embodiment of the present application may further provide a plurality of target material units to form a plurality of passivation stacks, wherein the number and shape of each mixed target material in each target material unit may be the same or different, and are not specifically limited in the embodiment of the present application.

[0159] Step 804 : Based on the target unit, physical vapor deposition is used to form a first doped amorphous silicon layer and a second doped amorphous silicon layer on a side of the tunnel passivation layer away from the substrate.

[0160] Please refer to Fig.11 The first doped amorphous silicon layer 1301 includes at least gallium element, and the second doped amorphous silicon layer 1302 includes at least boron element.

[0161] In the embodiments of the present application, physical vapor deposition includes but is not limited to vacuum evaporation (for example, thermal evaporation such as resistance heating, high-frequency induction heating, and electron beam, laser beam and ion beam evaporation, etc.), magnetron sputtering, reactive plasma plating (RPD), arc plasma plating, etc.

[0162] For ease of explanation, in the embodiment of the present application, physical vapor deposition including magnetron sputtering and electron beam evaporation is used as an example for explanation. Exemplarily, step 804 may specifically include the step of forming a first doped amorphous silicon layer (e.g., a gallium-doped amorphous silicon layer) and a second doped amorphous silicon layer 1302 (e.g., a boron-doped amorphous silicon layer) on the side of the tunnel passivation layer away from the substrate by magnetron sputtering based on the mixed gas and each mixed material target. Optionally, step 704 may specifically include bombarding each mixed material target in the target unit with a high-energy electron beam in a deposition order, and depositing a first doped amorphous silicon layer 1301 and a second doped amorphous silicon layer 1302 on the side of the tunnel passivation layer away from the substrate.

[0163] Step 806, performing annealing treatment.

[0164] Please continue to refer to Fig.11 , the structure obtained in the above step 804 is annealed to form a first doped layer and a second doped layer at least on the side of the tunnel passivation layer away from the substrate. Exemplarily, the structure obtained in step 704 can be placed in a tubular annealing furnace for annealing, and its first doped amorphous silicon layer 1301 (for example, a gallium-doped amorphous silicon layer) can be converted into a gallium-doped polycrystalline silicon layer, that is, the first doped layer 131; its second doped amorphous silicon layer 1302 (for example, a boron-doped amorphous silicon layer) can be converted into a boron-doped polycrystalline silicon layer, that is, the second doped layer 132. Exemplarily, its annealing temperature can be 880°C-1050°C, for example, its annealing temperature can be 880°C, 895°C, 910°C, 925°C, 940°C, 955°C, 970°C, 985°C, 1000°C, or 1050°C. It should be noted that its annealing temperature is not limited to the above examples, and can also be other temperatures.

[0165] In an exemplary embodiment, the first doping layer 131 and the second doping layer 132 may be formed by magnetron sputtering in physical vapor deposition. The mixed gas of magnetron sputtering may include a sputtering gas and a doping gas. The sputtering gas may include argon gas, and the doping gas may include a gallium source precursor and a boron source precursor. Exemplarily, the gallium source precursor includes but is not limited to trimethylgallium (TMGa), so that out-of-source doping (Ga target and trimethylgallium precursor source dissociation) can be achieved to increase the doping concentration. Exemplarily, the boron source precursor includes but is not limited to at least one of hexahydroboron (B2H6) and trimethyl borate (TMB), so that out-of-source doping (B target and boron source precursor source dissociation) can be achieved to increase the doping concentration.

[0166] Exemplarily, argon is used as a sputtering gas and a gallium source precursor is used as a doping gas to bombard a gallium-doped mixed material target 101 to form a gallium-doped amorphous silicon layer 1301. Afterwards, on the basis of the gallium-doped amorphous silicon layer 1301, argon is used as a sputtering gas and a boron source precursor is used as a doping gas to bombard a boron-doped mixed material target 102 to form a boron-doped amorphous silicon layer 1302, thereby forming a doped amorphous silicon stack including the gallium-doped amorphous silicon layer 1301 and the boron-doped amorphous silicon layer 1302.

[0167] In an exemplary embodiment, the gallium-doped amorphous silicon layer 1301 may have a thickness of 5 nm-100 nm. For example, the gallium-doped amorphous silicon layer 1301 may have a thickness of 5 nm, 10 nm, 15 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm. The boron-doped amorphous silicon layer 1302 may have a thickness of 10 nm-200 nm. For example, the gallium-doped amorphous silicon layer 1301 may have a thickness of 10 nm, 15 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm.

[0168] In this embodiment, a gallium-doped amorphous silicon layer and a boron-doped amorphous silicon layer are formed on the tunnel passivation layer by magnetron sputtering technology, and the obtained structure is annealed to form the first doping layer 131 and the second doping layer 132. The magnetron sputtering technology is closer to mass production conditions, which can achieve a large area, high production capacity, stable and controllable process, and can also simplify the process steps of forming the first doping layer 131 and the second doping layer 132, greatly reducing the process cost. In addition, by using a gallium-doped mixed material target 101 and a boron-doped mixed material target 102 and using a gallium source precursor and a boron source precursor, the stability and uniformity of magnetron sputtering can be improved, and the yield rate of solar cell preparation can be improved.

[0169] In an exemplary embodiment, the gallium-doped mixed material target 101 includes a mixed material of silicon and gallium elements, and the ratio of gallium element to silicon is 1 / 2000-1 / 25. Exemplarily, the ratio of gallium element to silicon may be 1 / 2000, 1 / 1000, 1 / 500, 1 / 250, 1 / 125, 1 / 75, 1 / 50 or 1 / 25. The boron-doped mixed material target 102 includes a mixed material of silicon and boron elements, and the ratio of boron element to silicon is 1 / 2000-1 / 25. Exemplarily, the ratio of boron element to silicon may be 1 / 2000, 1 / 1000, 1 / 500, 1 / 250, 1 / 125, 1 / 75, 1 / 50 or 1 / 25. It should be noted that the values ​​of the ratios of gallium element and boron element to silicon are not limited to the aforementioned examples, and can also be other ratio values.

[0170] In the embodiments of the present application, by setting the ratio of gallium to silicon in the gallium-doped mixed material target and the ratio of boron to silicon in the boron-doped mixed material target, both the interface recombination and the contact resistivity can be reduced, thereby improving the stability of the solar cell and improving the yield rate of the solar cell.

[0171] In an exemplary embodiment, the doping gas includes a gallium source precursor and a boron source precursor. The doping percentage of the gallium source precursor is 0.1%-10%, and the doping percentage of the boron source precursor is 0.1%-10%. Exemplarily, the doping percentage of the gallium source precursor and the doping percentage of the boron source precursor may be 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%, respectively. It should be noted that the values ​​of the doping percentage of the gallium source precursor and the doping percentage of the boron source precursor are not limited to the above examples, but may also be other percentages. By adjusting the doping percentage of the gallium source precursor and the doping percentage of the boron source precursor, the doping concentration can be increased, thereby reducing interface recombination and reducing contact resistivity.

[0172] Optionally, in addition to the gallium source precursor and the boron source precursor, the doping gas may also include at least one of methane, carbon dioxide and ammonia. During the magnetron sputtering process, the passivation performance and optical properties of the doped polysilicon layer can be adjusted by introducing an appropriate amount of doping gases such as methane, carbon dioxide, ammonia, etc. Exemplarily, the doping percentage of methane is 10%-50%, for example, 10%, 20%, 30%, 40%, 50%; the doping percentage of ammonia is 0.5%-30%, for example, 0.5%, 10%, 20%, 30%; the doping percentage of carbon dioxide is 0.1%-50%, for example, 0.1%, 10%, 20%,

[0173] 30%, 40%, 50%. It should be noted that the doping percentages of methane, carbon dioxide and ammonia can be any values ​​within their respective corresponding value ranges. By setting the doping percentages of methane, carbon dioxide and ammonia, the passivation performance and optical properties of the doped polysilicon layer can be further optimized.

[0174] In an exemplary embodiment, a heating device may be provided in the PVD process chamber to control the temperature of the substrate on the carrier. Exemplarily, the temperature of the substrate may be 200°C-450°C by means of the heating device. For example, the substrate temperature may be 200°C, 250°C, 275°C, 300°C, 325°C, 350°C, 375°C, 400°C, 420°C or 450°C. It should be noted that the substrate temperature is not limited to the aforementioned examples, and may also be any value between 200°C-450°C. In this way, by controlling the temperature of the substrate to maintain it between 200°C-450°C, the stability and uniformity of the gallium-doped amorphous silicon layer 1301 and the boron-doped amorphous silicon layer 1302 formed by magnetron sputtering may be further improved, and the yield rate of solar cell preparation may be improved.

[0175] In an exemplary embodiment, different from the above-mentioned embodiment, the physical vapor deposition provided in this embodiment is electron beam evaporation in vacuum evaporation. In this embodiment, the preparation method of the solar cell is described by taking electron beam evaporation as an example. Step 804 may specifically include bombarding each mixed material target in the target unit with a high-energy electron beam in a deposition order, and depositing a first doped amorphous silicon layer 1301 and a second doped amorphous silicon layer 1302 on the side of the tunnel passivation layer away from the substrate. Exemplarily, the gallium-doped mixed material target 101 is bombarded by a first high-energy electron beam to evaporate gallium and deposit it on the side of the tunnel passivation layer 120 away from the substrate, thereby forming a gallium-doped amorphous silicon layer 1301. Exemplarily, the deposition rate of the gallium-doped amorphous silicon layer 1301 is 0.1-5nm / min, and the thickness of the gallium-doped amorphous silicon layer 1301 formed is 5nm-100nm. The boron-doped mixed material target 102 is bombarded by a second high-energy electron beam to evaporate gallium and deposit it on the side of the tunnel passivation layer 120 away from the substrate, thereby forming a boron-doped amorphous silicon layer 1302. Exemplarily, the deposition rate of the boron-doped amorphous silicon layer 1302 is 0.1-5 nm / min, and the thickness of the formed boron-doped amorphous silicon layer 1302 is 10 nm-200 nm.

[0176] Optionally, a heating device may be provided in the electron beam process chamber to control the temperature of the substrate on the carrier. Exemplarily, the temperature of the substrate may be 200°C-450°C by the heating device. Thus, by controlling the temperature of the substrate to maintain it between 200°C-450°C, the stability and uniformity of the gallium-doped amorphous silicon layer 1301 and the boron-doped amorphous silicon layer 1302 formed by electron beam evaporation may be further improved, and the yield rate of solar cell preparation may be improved.

[0177] In this embodiment, electron beam evaporation is used to form a gallium-doped amorphous silicon layer and a boron-doped amorphous silicon layer on the tunnel passivation layer, and then an annealing process is used to form the first doping layer and the second doping layer. The electron beam evaporation is closer to mass production conditions, which can achieve a large area, high production capacity, stable and controllable process, and can also simplify the process steps of forming the first doping layer and the second doping layer, greatly reducing the process cost. In addition, the deposition rate can be increased and the efficiency of the coating can be improved.

[0178] It should be noted that the physical vapor deposition used to form the P-type passivation stack 130 is not limited to the above-mentioned magnetron sputtering and electron beam evaporation, but can also be reactive plasma plating (RPD), arc plasma plating, or thermal evaporation in vacuum evaporation, laser beam or ion beam evaporation, which will not be explained one by one here.

[0179] In an exemplary embodiment, the method for preparing a solar cell may further provide at least two target material units, and for each target material unit, a first doped amorphous silicon layer 1301 and a second doped amorphous silicon layer 1302 are formed on the target structure in the thickness direction based on physical vapor deposition, and an annealing treatment is performed to form alternatingly arranged first doped layers and second doped layers on the side of the tunneling passivation layer away from the substrate.

[0180] The solar cell preparation method may be based on multiple target units, using magnetron sputtering technology or electron beam evaporation to form alternating first doped amorphous silicon layers 1301 and second doped amorphous silicon layers 1302 on the side of the tunnel passivation layer 120 away from the substrate.

[0181] In the embodiment of the present application, for the convenience of explanation, the first doped amorphous silicon layer 1301 and the second doped amorphous silicon layer 1302 are used as an example to explain the doped amorphous silicon unit. For example, one target unit corresponds to forming a doped amorphous silicon stack. The doping concentration of the doping element of each target material in each target material unit is different, or the number of each target material in each target material unit, the area of ​​the target material, etc. are different. Exemplarily, the formation of two doped amorphous silicon units by magnetron sputtering is used as an example for explanation.

[0182] First, a gallium-doped mixed target of the first target unit is used to form a first gallium-doped amorphous silicon layer 1301 on the side of the tunneling passivation layer 120 away from the substrate by magnetron sputtering; then, in the same PVD chamber, based on the boron-doped mixed target in the first target unit, a first boron-doped amorphous silicon layer 1302 is formed on the side of the first gallium-doped amorphous silicon layer 1301 away from the tunneling passivation layer 120; then, in the same PVD chamber, based on the gallium-doped mixed target in the second target unit, a second gallium-doped amorphous silicon layer 1301 is formed on the side of the first boron-doped amorphous silicon layer 1302 away from the tunneling passivation layer 120; finally, in the same PVD chamber, based on the boron-doped mixed target in the second target unit, a second boron-doped amorphous silicon layer 1302 is formed on the side of the second gallium-doped amorphous silicon layer 1301 away from the tunneling passivation layer 120. In this way, a plurality of doped amorphous silicon units arranged in layers can be formed by continuously arranging a plurality of target material units, and finally, a plurality of first doped layers and second doped layers arranged in layers alternately can be formed by an annealing process.

[0183] In this embodiment, magnetron sputtering technology is used to form a plurality of alternatingly stacked first doping layers and second doping layers, which can simplify the process steps of forming the first doping layer and the second doping layer and significantly reduce the process cost. In addition, this technology can be closer to mass production conditions, and can achieve a large area, high capacity, stable and controllable process; it can also improve the passivation effect, reduce the contact resistivity, and significantly reduce the cost.

[0184] Optionally, based on multiple target units, multiple doped amorphous silicon units can be formed by electron beam evaporation on the side of the tunnel passivation layer away from the substrate. For example, multiple target units can be continuously arranged in the corresponding electron beam process chamber, and the corresponding target units can be bombarded in the deposition order to form multiple stacked doped amorphous silicon units. Finally, an annealing treatment is performed to form multiple alternating stacked first doped layers and second doped layers. In this way, the process steps for forming the P-type passivation stack can be simplified, and the process cost can be greatly reduced. In addition, this technology can be closer to mass production conditions, which can achieve large-area, high-capacity, stable and controllable process; it can also improve the passivation effect, reduce the contact resistivity, and greatly reduce the cost.

[0185] In an exemplary embodiment, in the process of preparing a solar cell, before forming the first doped amorphous silicon layer, the method for preparing a solar cell may further include providing an initial target material, and forming an interface amorphous silicon layer on a side of the tunnel passivation layer away from the substrate based on the initial target material. The first doped amorphous silicon layer is located on a side of the interface amorphous silicon layer away from the tunnel passivation layer.

[0186] The arrangement order of the initial target 103, the gallium-doped mixed material target 101, and the boron-doped mixed material target 102 can be referred to Fig. 9 and Fig.10 The step of providing the initial target material and the step of providing at least one gallium-doped mixed material target material 101 and at least one boron-doped mixed material target material 102 may be performed simultaneously or at different times. The initial target material 103 may be understood as an undoped intrinsic target material or a lightly doped target material. Before forming the first doped amorphous silicon layer 1301, argon gas may be used as a sputtering gas to bombard the initial target material 103 on the tunnel passivation layer 120 away from the substrate 110 to form an interface amorphous silicon layer 1303, such as Fig.12 As shown. On this basis, a gallium-doped amorphous silicon layer 1301 and a boron-doped amorphous silicon layer 1302 are further formed on the interface amorphous silicon layer 1303. Then, annealing treatment is performed, and the doping elements in the interface amorphous silicon layer 1303, the gallium-doped amorphous silicon layer 1301 and the boron-doped amorphous silicon layer 1302 are activated and begin to diffuse, which can further improve the passivation performance of the solar cell.

[0187] Optionally, in the process of forming the doped amorphous silicon stack on the side of the tunnel passivation layer away from the substrate by electron beam evaporation, the initial target material 103 (see Fig. 9 and Fig.10 ), before forming the gallium-doped amorphous silicon layer, the initial target 103 can be bombarded by a high-energy electron beam to form an interface amorphous silicon layer on the tunnel passivation layer away from the substrate.

[0188] In an exemplary embodiment, before forming the second doped amorphous silicon layer 1302 , the method for preparing a solar cell further includes the step of forming a first interface oxide layer on a side of the first doped amorphous silicon layer 1301 away from the tunnel passivation layer.

[0189] like Fig.13 For example, the first interface oxide layer 140 may be formed on the side of the gallium-doped amorphous silicon layer away from the tunnel passivation layer by physical vapor deposition, chemical vapor deposition, etc. The material of the first interface oxide layer 140 may be a dielectric material, such as at least one of silicon oxide, magnesium fluoride, silicon oxide, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide, or titanium oxide.

[0190] For example, the first interface oxide layer 140 may be formed by physical vapor deposition using the same process technology as that for forming the doped amorphous silicon layer, thereby further reducing the cost. Exemplarily, the gallium-doped amorphous silicon layer 1301 is formed based on physical vapor deposition, the first interface oxide layer 140 is formed on a side of the gallium-doped amorphous silicon layer 1301 away from the tunnel passivation layer, and then the boron-doped amorphous silicon layer is formed on the first interface oxide layer 140 based on physical vapor deposition.

[0191] In this example, by forming a first interface oxide layer between the first doping layer and the second doping layer, the diffusion rate of the boron element can be alleviated to avoid excessive concentration of the B element destroying the passivation effect of the ultra-thin tunneling passivation layer, and the passivation performance between the first doping layer and the second doping layer can also be improved.

[0192] In an exemplary embodiment, after forming a first doped amorphous silicon layer 1301 and a second doped amorphous silicon layer 1302 on the target structure based on physical vapor deposition in the thickness direction of each target material unit, the solar cell preparation method may further include: a step of forming a second interface oxide layer on a side of the second gallium-doped amorphous silicon layer away from the first gallium-doped amorphous silicon layer.

[0193] It is understandable that after forming the first doped amorphous silicon layer 1301 and the second doped amorphous silicon layer 1302 for each target material unit, a second interface oxide layer may be further formed on the side of the second gallium-doped amorphous silicon layer away from the first gallium-doped amorphous silicon layer. The formation method of the second interface oxide layer also refers to the formation method of the first interface oxide layer, which will not be described in detail here. By forming the second interface oxide layer between the two doped amorphous silicon units, the solar cell can have a more excellent passivation performance.

[0194] For the sake of convenience, the following is an example of how to form a solar cell by magnetron sputtering. Figure 2 The method for preparing the solar cell shown may specifically include the following steps:

[0195] Step 1: Select N-type silicon with a thickness of 130 μm as the substrate 110, and remove the surface cutting damage layer by an alkali polishing process.

[0196] Step 2: Place N-type silicon in a plate-type PECVD device to deposit a tunnel passivation layer 120, such as SiOx. For example, N2O and Ar are used as reaction gases to prepare a 1-2 nm tunnel passivation layer 120 at a temperature of 400-500°C.

[0197] Step 3, continuously transfer the silicon wafer to the PVD process chamber, and place multiple targets in parallel for depositing the doped polysilicon layer. Exemplarily, using Ar as the sputtering gas, the silicon wafer deposits the interface amorphous silicon layer through the intrinsic target or the lightly doped target; deposits the Ga-doped amorphous silicon layer through the doped Ga target; and deposits the B-doped amorphous silicon layer through the doped B target. The thickness of the Ga-doped amorphous silicon layer is 5-100nm, and the thickness of the B-doped amorphous silicon layer is 10-200nm. Among them, the Ga source precursor is used as the doping gas, and the doping percentage is about 0.1%-10%, and the B source is used as the doping gas, and the doping percentage is about 0.1%-10%. In addition, the Ga source and the B source can be doped with hydrogen, and an appropriate amount of methane or oxygen can be introduced to adjust the light transmittance of the polysilicon film. During the sputtering process, the temperature of the substrate 110 can be maintained at 200-450° C., which can further improve the stability and uniformity of the gallium-doped amorphous silicon layer and the boron-doped amorphous silicon layer formed by magnetron sputtering, and can improve the yield rate of solar cell preparation.

[0198] Step 4: Finally, N2O and Ar are used as reaction gases to deposit a 10-40 nm thick silicon oxide layer as a protective layer.

[0199] Step 5: Then, the amorphous silicon layer is placed in a tubular annealing furnace for annealing at 880-1050° C., and the doping elements in the amorphous silicon layer are activated and diffused toward the silicon substrate 110 .

[0200] Step 6: remove SiOx on the front surface of the silicon substrate 110 by single-sided chain HF, and then polish the front surface of the silicon substrate 110 by alkali polishing.

[0201] Step 7, prepare N-type passivated polysilicon 173 by PECVD process. For example, annealing can be performed at 880-950° C. in a tubular annealing furnace. Then, PSG other than polysilicon fingers is removed by laser etching process, and n-Ploy is etched by alkaline solution to prepare the front surface texturing structure.

[0202] Step 8, deposit AlOx and SiNx to form a passivation anti-reflection layer on the front and back sides of the silicon substrate 110. For example, the front side aluminum oxide 184 (a layer close to the substrate) can be deposited by atomic layer deposition (ALD) technology, with a thickness range of 5nm; then, silicon nitride / silicon oxynitride 184 (a layer away from the substrate) and 185 are deposited on the front and back sides, with a thickness range of 85nm and a refractive index range of 1.8-2.2.

[0203] Step 9, print the main grid and fine grid metal electrodes on the front and back sides simultaneously through the screen printing process, and further improve the passivation through the sintering photoannealing process to complete the device preparation.

[0204] It should be noted that the method for preparing solar cells is not limited to the above-mentioned examples. The various preparation process steps can be adjusted accordingly according to different types of solar cells. In the embodiments of the present application, the method for preparing solar cells suitable for the present application and the specific structure of the solar cells are not specifically limited.

[0205] Fig.14 This is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of the present application. Fig.14 This embodiment provides a photovoltaic module 200, including at least one battery string 210, the battery string 210 includes at least two solar cells 100 in any of the aforementioned embodiments, and the solar cells 100 can be connected together by serial welding.

[0206] For example, multiple solar cells can be connected in series by welding ribbons, so that the electric energy generated by a single solar cell can be collected for subsequent transmission. Of course, the solar cells can be arranged at intervals or stacked in a shingled form.

[0207] Exemplarily, the photovoltaic module 200 also includes an encapsulation layer and a cover plate (not shown), the encapsulation layer is used to cover the surface of the battery string 210, and the cover plate is used to cover the surface of the encapsulation layer away from the battery string 210. The solar cells are electrically connected in the form of a whole piece or multiple pieces to form a plurality of battery strings 210, and the plurality of battery strings 210 are electrically connected in series and / or in parallel. Specifically, in some embodiments, the plurality of battery strings 210 can be electrically connected by a conductive tape. The encapsulation layer covers the surface of the solar cell. For example, the encapsulation layer can be an organic encapsulation film such as an ethylene-vinyl acetate copolymer film, a polyethylene octene co-elastic film, or a polyethylene terephthalate film. The cover plate can be a cover plate with a light-transmitting function such as a glass cover plate, a plastic cover plate, etc.

[0208] In the description of this specification, the description with reference to the terms "one embodiment", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0209] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are 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 of this specification.

[0210] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for preparing a solar cell, characterized in that: include: Providing a substrate, the substrate comprising a first surface and a second surface arranged opposite to each other along a thickness direction of the substrate; forming a tunnel passivation layer on the first surface of the substrate; Based on physical vapor deposition, a first doping layer and a second doping layer are stacked at least on a side of the tunneling passivation layer away from the substrate, wherein the doping types of the first doping layer and the second doping layer are both P-type, and the doping elements of the first doping layer and the second doping layer are not completely the same, the first doping layer at least includes gallium, and the second doping layer at least includes boron.

2. The method according to claim 1, characterized in that The method of forming a first doping layer and a second doping layer by stacking at least one side of the tunnel passivation layer away from the substrate based on physical vapor deposition comprises: Providing a target unit; wherein the target unit comprises a gallium-doped mixed material target and a boron-doped mixed material target, and the gallium-doped mixed material target and the boron-doped mixed material target are arranged in a deposition order; Based on the target unit, a first doped amorphous silicon layer and a second doped amorphous silicon layer are formed on the side of the tunnel passivation layer away from the substrate by physical vapor deposition; wherein the first doped amorphous silicon layer includes at least gallium element, and the second doped amorphous silicon layer includes at least boron element; An annealing process is performed to form the first doping layer and the second doping layer.

3. The method according to claim 2, characterized in that The method of forming a first doped amorphous silicon layer and a second doped amorphous silicon layer on a side of the tunnel passivation layer away from the substrate by physical vapor deposition comprises: Based on the mixed gas and the target material unit, magnetron sputtering is used to form the first doped amorphous silicon layer and the second doped amorphous silicon layer on the tunnel passivation layer away from the substrate; wherein the mixed gas includes a sputtering gas and a doping gas.

4. The method according to claim 3, characterized in that The doping gas includes a gallium source precursor and a boron source precursor.

5. The method according to claim 4, characterized in that The gallium source precursor includes trimethylgallium, and the boron source precursor includes at least one of hexahydroboron and trimethyl borate.

6. The method according to claim 3, characterized in that The doping gas also includes at least one of methane, carbon dioxide and ammonia.

7. The method according to claim 6, characterized in that The doping gas includes the methane, the carbon dioxide and the ammonia; wherein the doping percentage of the methane is 10%-50%, the doping percentage of the ammonia is 0.5%-30%, and the doping percentage of the carbon dioxide is 0.1%-50%.

8. The method according to claim 2, characterized in that: The method of forming a first doped amorphous silicon layer and a second doped amorphous silicon layer on a side of the tunnel passivation layer away from the substrate by physical vapor deposition comprises: The first doped amorphous silicon layer and the second doped amorphous silicon layer are deposited on a side of the tunnel passivation layer away from the substrate by bombarding each of the mixed material targets in the target unit in the deposition order with a high energy electron beam.

9. The method according to claim 2, characterized in that: The target unit includes at least two of the gallium-doped mixed material targets and at least two of the boron-doped mixed material targets; Among them, the gallium-doped mixed material targets are arranged adjacent to each other, and the boron-doped mixed material targets are arranged adjacent to each other.

10. The method according to claim 1, characterized in that The number of the first doping layer and the number of the second doping layer are at least two respectively; The first doping layers and the second doping layers are alternately formed on a side of the tunnel passivation layer away from the substrate.

11. The method according to claim 10, characterized in that The first doped layers and the second doped layers are alternately formed on a side of the tunnel passivation layer away from the substrate, comprising: Providing at least two target material units; the target material units include a gallium-doped mixed material target and a boron-doped mixed material target, and the gallium-doped mixed material target and the boron-doped mixed material target are arranged in a deposition order; For each of the target material units, in the thickness direction, a first doped amorphous silicon layer and a second doped amorphous silicon layer are formed on the target structure based on physical vapor deposition; wherein the target structure includes a tunnel passivation layer or each of the second doped amorphous silicon layers; Annealing is performed to form the first doped layers and the second doped layers that are alternately arranged on the side of the tunnel passivation layer away from the substrate.

12. The method according to claim 2 or 11, characterized in that: Before forming the first doped amorphous silicon layer, the method further includes: Providing an initial target material, wherein the initial target material is disposed adjacent to the gallium-doped mixed material target material; An interfacial amorphous silicon layer is formed on a side of the tunneling passivation layer away from the substrate based on the initial target; wherein the first doped amorphous silicon layer is located on a side of the interfacial amorphous silicon layer away from the tunneling passivation layer.

13. The method according to claim 12, characterized in that The initial target material includes an intrinsic target material not doped with a P-type element or a mixed target material lightly doped with a P-type element.

14. The method according to claim 2 or 11, characterized in that: Before forming the second doped amorphous silicon layer, the method further includes: A first interface oxide layer is formed on a side of the first doped amorphous silicon layer away from the tunnel passivation layer; wherein the second doped amorphous silicon layer is formed on a side of the first interface oxide layer away from the first doped amorphous silicon layer.

15. The method according to claim 11, characterized in that After forming the first doped amorphous silicon layer and the second doped amorphous silicon layer on the target structure based on physical vapor deposition in the thickness direction for each of the target material units, the method further comprises: A second interface oxide layer is formed on a side of the second gallium-doped amorphous silicon layer away from the first gallium-doped amorphous silicon layer.

16. The method according to claim 1, characterized in that The physical vapor deposition also includes one of vacuum evaporation and arc plasma plating.

17. A solar cell, characterized in that: include: A substrate, comprising a first surface and a second surface arranged opposite to each other along a thickness direction of the substrate; A tunnel passivation layer, located on the first surface of the substrate; A first doped layer, located on a side of the tunnel passivation layer away from the substrate; a second doped layer, located on a side of the first doped layer away from the tunnel passivation layer; The doping types of the first doping layer and the second doping layer are both P-type, and the doping elements of the first doping layer and the second doping layer are not completely the same, the first doping layer at least includes gallium, and the second doping layer at least includes boron; An electrode is in contact with the second doping layer.

18. The solar cell according to claim 17, characterized in that: The doping element of the first doping layer includes gallium; The doping element of the second doping layer includes boron, or the doping element of the second doping layer includes boron and gallium.

19. The solar cell according to claim 17, characterized in that: The solar cell includes at least two first doping layers and at least two second doping layers, wherein in the thickness direction, each of the first doping layers and each of the second doping layers are alternately located on a side of the tunneling passivation layer away from the substrate.

20. The solar cell according to claim 19, characterized in that In a direction from the substrate to the tunnel passivation layer, the concentration of the gallium element in each of the first doping layers gradually decreases.

21. The solar cell according to claim 20, characterized in that The maximum concentration range of gallium in each of the first doping layers is 8E19cm -3 -12E19 / cm -3 .

22. The solar cell according to claim 19, characterized in that In a direction from the substrate to the tunnel passivation layer, the concentration of the boron element in each of the second doping layers gradually decreases.

23. The solar cell according to claim 22, characterized in that The maximum concentration range of the boron element in each of the second doping layers is 5E19cm -3 -11E19 / cm -3 .

24. The solar cell according to claim 17, characterized in that: The thickness of the first doping layer is in the range of 10 nm to 150 nm, and the thickness of the second doping layer is in the range of 5 nm to 150 nm.

25. The solar cell according to claim 17, characterized in that The solar cell further comprises: A first interface oxide layer, in the thickness direction, the first interface oxide layer is located between the first doping layer and the second doping layer.

26. The solar cell according to claim 19, characterized in that The solar cell further comprises: A second interface oxide layer, in the thickness direction, the second interface oxide layer is located on a side of the second doping layer away from the first doping layer.

27. The solar cell according to claim 17, characterized in that The solar cell further comprises: The interface polysilicon layer is located on a side of the tunnel passivation layer away from the substrate in the thickness direction; wherein the first doped layer is located on a side of the interface polysilicon layer away from the tunnel passivation layer.

28. The solar cell according to claim 17, characterized in that The first doping layer and the second doping layer are both prepared by physical vapor deposition.

29. The solar cell according to claim 28, characterized in that The physical vapor deposition includes one of vacuum evaporation, magnetron sputtering, reactive plasma plating and arc plasma plating.

30. The solar cell according to any one of claims 17 to 29, characterized in that: The first surface is a backlight surface; wherein the solar cell further comprises: A first passivation anti-reflection layer is located on a side of the second doped layer away from the first doped layer; A first polysilicon conductive layer, a second passivation anti-reflection layer, a second polysilicon conductive layer and a conductive passivation layer are stacked on the second surface of the substrate; wherein the doping types of the first polysilicon conductive layer and the second polysilicon conductive layer are both N-type; A first electrode and a second electrode; wherein the first electrode is disposed on one side of the second surface of the substrate and contacts the conductive passivation layer, and the second electrode is disposed on one side of the first surface of the substrate and contacts the second doping layer.

31. The solar cell according to any one of claims 17 to 29, characterized in that: The first surface is a backlight surface, and the second surface includes a first area and a second area; wherein the solar cell further includes: At least one third polysilicon conductive layer, stacked in the first region; the doping type of the third polysilicon conductive layer is N-type; At least one third passivation anti-reflection layer, stacked in the second region; At least one fourth passivation anti-reflection layer, stacked on a side of the second doped layer away from the first doped layer; A first electrode and a second electrode; wherein the first electrode is disposed on one side of the second surface of the substrate and contacts the third polysilicon conductive layer, and the second electrode is disposed on one side of the first surface of the substrate and contacts the second doped layer.

32. The solar cell according to any one of claims 17 to 29, characterized in that: The first surface is a light-receiving surface, and the first surface includes a third region and a fourth region, wherein the tunnel passivation layer is located in the third region of the first surface; wherein the solar cell further includes: A tunneling oxide layer, a third doping layer and a fifth passivation subtractive layer are stacked on the second surface of the substrate, wherein the doping type of the third doping layer is different from the doping type of the first doping layer; a sixth passivation anti-reflection layer, located on a side of the second doped layer away from the first doped layer and located in a fourth region of the first surface; A first electrode and a second electrode; wherein the first electrode is disposed on one side of the first surface of the substrate and contacts the second doped layer, and the second electrode is disposed on one side of the second surface of the substrate and contacts the third doped layer.

33. A photovoltaic module, characterized in that: The invention comprises at least one battery string, wherein the battery string comprises at least two solar cells manufactured by the method for manufacturing a solar cell according to any one of claims 1 to 16, or the solar cell according to any one of claims 17 to 32.

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