Solar cell and its manufacturing method

Abstract

An embodiment of the present disclosure relates to the field of photovoltaics, and provides a solar cell and a manufacturing method thereof. The manufacturing method includes the steps of: providing a substrate having a first surface and a second surface facing each other; performing a doping process on at least the first surface to form a doped layer having a first doping element; performing a first laser process on a portion of the doped layer to form an activated portion and leaving the remaining doped layer as a doped portion; performing a first etching process on the first surface, using the remaining doped layer as a dead layer, to remove the activated portion and form a first textured surface; forming a doped polysilicon layer and a silicate glass layer having a second doping element at least on a side of the substrate away from the doped portion; performing a second laser process on at least a portion of the silicate glass layer to form a sparse portion; and performing a second etching process on at least the second surface, using the remaining silicate glass layer as a protective layer, to remove the sparse portion and the doped polysilicon layer facing the sparse portion and form a second textured surface. The first laser process and the second laser process use different laser types, thereby simplifying at least the manufacturing process.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to the field of photovoltaics, and more particularly to solar cells and methods for their manufacture. [Background technology]

[0002] As fossil fuels are gradually being depleted, solar cells are becoming more and more widely used as a new alternative energy source. Solar cells are devices that convert solar light energy into electrical energy. Solar cells utilize the photovoltaic principle to generate carriers, which are then extracted using electrodes, making them advantageous for the effective use of electrical energy.

[0003] Current solar cells mainly include IBC cells (Interdigitated Back Contact), TOPCON (Tunnel Oxide Passivated Contact) cells, PERC cells (Passivated Emitter and Rear Cell) and heterojunction solar cells.

[0004] However, the photoelectric conversion efficiency of solar cells formed by different manufacturing methods differs, and there is a demand for the development of a more advantageous manufacturing method that improves the photoelectric conversion efficiency of solar cells or simplifies the manufacturing process. Summary of the Invention

[0005] The embodiments of the present disclosure provide a solar cell and a method for manufacturing the same that are advantageous in at least simplifying the manufacturing process of the solar cell and improving the photoelectric conversion efficiency of the solar cell.

[0006] According to some embodiments of the present disclosure, in one aspect of the embodiments of the present disclosure, a method for manufacturing a semiconductor device includes the steps of: providing a substrate having a first surface and a second surface facing each other; performing a doping process on at least the first surface to form a doped layer having a first doping element; performing a first laser process on a part of the doped layer to form an activated portion and forming the remaining doped layer as a doped portion, and making the doping concentration of the first doping element in the activated portion lower than the doping concentration of the first doping element in the doped portion; performing a first etching process on the first surface with the doped portion as a dead layer to remove the activated portion and form a first textured surface; The present invention provides a method for manufacturing a solar cell, the method including the steps of: sequentially forming a doped polysilicon layer having a second doping element and a silicate glass layer on a side of the substrate away from the doped portion; performing a second laser treatment on at least a portion of the silicate glass layer to form a sparse portion; and performing a second etching treatment on at least the second surface using the remaining silicate glass layer as a protective layer to remove the sparse portion and the doped polysilicon layer facing the sparse portion, thereby forming a second textured surface, wherein the first doping element and the second doping element are different types, and the first laser treatment and the second laser treatment use different types of lasers.

[0007] In another embodiment, the first surface and the second surface are both third textured surfaces, and the method further includes a step of performing a polishing process on the second surface to form a polished surface after forming the first textured surface and before forming the doped polysilicon layer, and the step of forming the doped polysilicon layer and the silicate glass layer includes a step of forming the doped polysilicon layer on the polished surface and a step of forming the silicate glass layer on a side of the doped polysilicon layer away from the polished surface.

[0008] In another embodiment, after forming the first textured surface and before forming the polished surface, the method further includes the steps of performing an oxidation treatment on at least the first surface to form a first diffusion barrier layer in the doped portion and a second diffusion barrier layer on the first textured surface, and the step of forming the doped polysilicon layer and the silicate glass layer further includes the steps of forming the doped polysilicon layer on both the first diffusion barrier layer and the second diffusion barrier layer, and forming the silicate glass layer on both sides of the doped polysilicon layer away from the first diffusion barrier layer and the second diffusion barrier layer.

[0009] In another embodiment, after forming the first textured surface and before forming the polished surface, the method further includes performing an oxidation treatment on at least the first surface to form a first diffusion barrier layer in the doped portion and a second diffusion barrier layer on the first textured surface, wherein a surface formed by both the first diffusion barrier layer and the second diffusion barrier layer includes an edge region and a central region surrounded by the edge region, and the step of forming the doped polysilicon layer and the silicate glass layer further includes forming the doped polysilicon layer in the edge region and forming the silicate glass layer on a side of the doped polysilicon layer away from the edge region.

[0010] In another embodiment, the first surface includes first laser regions and first non-laser regions arranged alternately along a first direction, the second surface includes second laser regions and second non-laser regions arranged alternately along the first direction, the step of performing the first laser treatment on a portion of the doped layer includes performing the first laser treatment on the doped layer located in the first laser region to form the activated portion located in the first laser region, and the step of performing the second laser treatment on at least a portion of the silicate glass layer includes performing the second laser treatment on the silicate glass layer located in the second laser region to form the sparse portion located in the second laser region.

[0011] In other embodiments, the orthogonal projection area of ​​the first laser region onto the substrate is different from the orthogonal projection area of ​​the second laser region onto the substrate, and / or the orthogonal projection of the first laser region onto the substrate at least partially overlaps or does not overlap with the orthogonal projection of the second laser region onto the substrate.

[0012] In another embodiment, the step of performing the second etching treatment on at least the second surface includes the steps of: etching the first surface using a second chain hydrofluoric acid process to remove the silicate glass layer located on the first surface; and etching the first surface and the second surface using a second texturing process to remove the doped polysilicon layer, the first diffusion barrier layer, and the second diffusion barrier layer located on the first surface to expose the first textured surface and the doped portion, and to remove the sparse portion and the doped polysilicon layer located in the second laser region to form the second textured surface.

[0013] In another embodiment, after performing the second texturing process, the method further includes cleaning the second surface using an acid cleaning process to remove the silicate glass layer located in the second non-laser areas and expose the doped polysilicon layer located in the second non-laser areas.

[0014] In another embodiment, performing the first etching process on the first surface includes etching the first surface using a first texturing process to remove the activated portion and form the first textured surface.

[0015] In another embodiment, the step of performing the first laser treatment includes forming an oxide layer on the doped layer, and the step of performing the first etching treatment on the first surface further includes etching the first surface using a first chain hydrofluoric acid process to remove the oxide layer before etching the first surface using the first texturing process.

[0016] In other embodiments, the first laser process uses a red nanosecond laser, a green nanosecond laser, or a violet nanosecond laser, and the second laser process uses a violet picosecond laser, a green picosecond laser, a green femtosecond laser, or a violet femtosecond laser.

[0017] According to another embodiment of the present disclosure, in another aspect of the embodiment of the present disclosure, there is provided a solar cell formed by the manufacturing method according to any one of the above aspects.

[0018] The technical solutions according to the embodiments of the present disclosure have at least the following advantages.

[0019] On the other hand, the first laser treatment activates a portion of the doped layer, reduces the doping concentration of the first doping element in the portion of the doped layer, and improves the regularity of the crystal lattice within the portion of the doped layer, thereby converting the portion of the doped layer into an activated portion and converting the remaining doped layer into a doped portion. In other words, compared to the doped portion, the doping concentration of the doping element in the activated portion is lower and the overall regularity of the crystal lattice within the activated portion is higher, so the doped portion is more easily etched under the same etching conditions. Based on this, when the first etching treatment is subsequently performed on the first surface, the etching rate of the activated portion, which has a lower doping concentration of the first doping element, is much higher than that of the doped portion. As a result, the doped portion can be treated as a dead layer and the activated portion can be removed to form a first textured surface without using a separate mask, which is advantageous for simplifying the solar cell manufacturing process. Furthermore, compared to removing a portion of the doped layer using a laser deposition process to form a selective emitter structure in which the doped layer remains only in a partial region of the first surface, the combined action of the first laser treatment and the first etching treatment is advantageous in reducing laser damage to the first surface, thereby reducing the surface defect state density of the first surface and improving the photoelectric conversion efficiency of the solar cell that is ultimately formed. Furthermore, forming a selective emitter structure in which the doped layer, i.e., the doped portion, remains only in a partial region of the first surface is advantageous in reducing the contact resistance between the subsequently formed electrode and the doped portion and reducing the probability of carrier recombination in other regions of the first surface.

[0020] On the other hand, the second laser treatment converts a portion of the silicate glass layer into a sparse portion, making the porosity of the sparse portion higher than that of the remaining silicate glass layer. Based on this, when a second etching treatment is subsequently performed on at least the second surface, the etching rate of the sparse portion with higher porosity by the second etching treatment is much higher than that of the remaining silicate glass layer. This allows the sparse portion and the doped polysilicon layer facing the sparse portion to be removed to form a second textured surface without providing a separate mask, using the remaining silicate glass layer as a protective layer, which is advantageous for simplifying the solar cell manufacturing process. Furthermore, removing the doped polysilicon layer facing the sparse portion is advantageous for avoiding parasitic absorption of light by the removed portion of the doped polysilicon layer. [Brief explanation of the drawings]

[0021] One or more embodiments are illustratively described by figures in the corresponding drawings, and these illustrative descriptions are not intended to limit the embodiments, and unless otherwise specified, the figures in the drawings are not intended to limit the scale. In order to more clearly describe the embodiments of the present disclosure or the technical means in the prior art, the drawings necessary for the embodiments are briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and those skilled in the art can also derive other drawings based on these drawings without any creative efforts.

[0022] [Figure 1] 1 is a partial cross-sectional structural schematic diagram of a substrate provided in a solar cell manufacturing method according to an embodiment of the present disclosure. [Figure 2] 1 is a partial cross-sectional structural schematic diagram formed after a doping treatment is performed on at least a first surface in a method for manufacturing a solar cell according to an embodiment of the present disclosure. [Figure 3] 1 is a schematic diagram of a partial cross-sectional structure formed after a first laser treatment is performed in a method for manufacturing a solar cell according to an embodiment of the present disclosure. [Figure 4] 3 is a schematic diagram of a partial cross-sectional structure formed after a first etching treatment is performed in a method for manufacturing a solar cell according to an embodiment of the present disclosure. FIG. [Figure 5] 2 is a partial cross-sectional structural schematic diagram formed after oxidation treatment is performed on at least the first surface in a method for manufacturing a solar cell according to an embodiment of the present disclosure. FIG. [Figure 6] 6 is a schematic partial cross-sectional view of the structure shown in FIG. 5 after polishing treatment is performed on the second surface. FIG. [Figure 7] FIG. 7 is a partial cross-sectional structural schematic diagram in which a doped polysilicon layer and a silicate glass layer are formed based on the structure shown in FIG. 6. [Figure 8] FIG. 10 is a schematic diagram of a partial cross-sectional structure formed after a second laser treatment is performed in a method for manufacturing a solar cell according to an embodiment of the present disclosure. [Figure 9] 9 is a schematic partial cross-sectional view of a structure formed after etching is performed on the first surface based on the structure shown in FIG. 8. FIG. [Figure 10] 10 is a schematic diagram of a partial cross-sectional structure formed after texturing is performed on the first and second surfaces based on the structure shown in FIG. 9. FIG. [Figure 11] 11 is a schematic diagram of a partial cross-sectional structure formed after cleaning is performed on the second surface based on the structure shown in FIG. 10. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] As can be seen from the background art, there is a need to simplify the manufacturing process of solar cells and improve the photoelectric conversion efficiency of solar cells.

[0024] The present disclosure provides a solar cell and a method for manufacturing the same, including a first laser treatment that activates a portion of the doped layer and reduces the doping concentration of a first doping element in the portion of the doped layer, thereby improving the regularity of the crystal lattice within the portion of the doped layer. In other words, the doping concentration of the doping element in the activated portion is lower than that in the doped portion, and the overall regularity of the crystal lattice within the activated portion is higher. Therefore, when a first etching treatment is subsequently performed on the first surface, the etching rate of the activated portion, which has a lower doping concentration of the first doping element, is much higher than that of the doped portion. This allows the doped portion to be treated as a dead layer and the activated portion to be removed to form a first textured surface without using a separate mask, which is advantageous for simplifying the solar cell manufacturing process. Furthermore, compared to removing a portion of the doped layer using a laser deposition process, the combined effect of the first laser treatment and the first etching treatment is advantageous in reducing laser damage to the first surface, thereby reducing the surface defect state density of the first surface and improving the photoelectric conversion efficiency of the ultimately formed solar cell. Furthermore, forming a selective emitter structure in which the doped portion remains only in a portion of the first surface is advantageous in reducing the contact resistance between the doped portion and an electrode to be formed subsequently and reducing the probability of carrier recombination in other regions of the first surface. On the other hand, if the second laser treatment is used to modify a portion of the silicate glass layer into a sparse portion, and then a second etching treatment is performed on at least the second surface based on this, the etching rate of the sparse portion, which has higher porosity, in the second etching treatment is much higher than that of the remaining silicate glass layer. Therefore, without providing a separate mask, the sparse portion and the doped polysilicon layer facing the sparse portion can be removed using the remaining silicate glass layer as a protective layer to form a second textured surface, which is advantageous in simplifying the solar cell manufacturing process. Removing the doped polysilicon layer facing the sparse portion is advantageous in avoiding parasitic absorption of light by the removed portion of the doped polysilicon layer.

[0025] In describing the embodiments of the present disclosure, the technical terms "first," "second," etc. are merely used to distinguish between different objects and should not be understood as indicating or suggesting relative importance, or as implicitly indicating the number, specific order, or hierarchical relationship of the technical features shown. In describing the embodiments of the present disclosure, "plurality" means two or more, unless otherwise clearly and specifically limited.

[0026] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. The appearance of the phrase in various places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is exclusive, independent, or an alternative to other embodiments. Those skilled in the art can explicitly or implicitly understand that the embodiments described herein can be combined with other embodiments.

[0027] In the description of the embodiments of the present disclosure, the term "and / or" merely describes the relationship between related objects and indicates that three relationships may exist. For example, A and / or B can represent three cases: A exists, A and B simultaneously exist, and B exists. Note that the character " / " in this specification generally indicates that the related objects before and after it are in an "or" relationship.

[0028] In describing the embodiments of the present disclosure, the term "plurality" refers to two or more (including two); similarly, "multiple sets" refers to two or more (including two sets); and "multiple sheets" refers to two or more (including two).

[0029] In describing the embodiments of the present disclosure, orientations or positional relationships indicated by technical terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" are based on the orientations or positional relationships shown in the drawings and are intended merely to facilitate and simplify the description of the embodiments of the present disclosure, and do not indicate or suggest that the depicted devices or parts must have a particular orientation, be configured, and operate in a particular orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0030] In describing the embodiments of the present disclosure, unless otherwise clearly specified or limited, the technical terms "attached," "coupled," "connected," "fixed," etc. should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, an internal communication between two parts, or an interactive relationship between two parts. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present disclosure according to the specific circumstances.

[0031] In the drawings corresponding to the embodiments of the present disclosure, the thicknesses and areas of layers are exaggerated for better understanding and ease of explanation. When a component (e.g., a layer, thin film, region, or substrate) is described as being on or on the surface of another component, the component may be located "directly" on the surface of the other component, or a third component may exist between the two components. Conversely, when a component is described as being on the surface of another component, or as being formed or provided on the surface of another component, it means that no third component exists between the two components. Furthermore, when a component is described as being "substantially" formed on the surface of another component, it means that the component is not formed on the entire surface (or front surface) of the other component, but is not formed on only a portion of the edge of the entire surface.

[0032] In describing the embodiments of the present disclosure, when a component "includes" another component, it does not exclude other components and may further include other components unless otherwise specified. Furthermore, when a component such as a layer, film, region, or plate is described as being "present / located on" another component, the component may be "directly" located on the other component (i.e., located on the surface of the other component, with no other components present between them), or there may be other components present between them. Furthermore, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it means that there is no other component present between them.

[0033] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments described and in the appended claims, "the member" is intended to include the plural unless the context clearly dictates otherwise. Members include elements such as layers, films, regions, or plates.

[0034] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. However, as can be understood by those skilled in the art, each embodiment of the present disclosure provides many technical details to help readers better understand the embodiments of the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical means that the embodiments of the present disclosure seek to protect can be realized.

[0035] An embodiment of the present disclosure provides a method for manufacturing a solar cell, and the method for manufacturing a solar cell according to the embodiment of the present disclosure will be described in detail below with reference to the drawings. Figures 1 to 11 are partial cross-sectional structural schematic diagrams corresponding to each step in the method for manufacturing a solar cell according to the embodiment of the present disclosure.

[0036] As shown in FIGS. 1 to 11, the method for manufacturing a solar cell includes at least the following steps S1 to S7.

[0037] In step S1, FIG. 1 is a partial cross-sectional structural schematic diagram of a substrate provided in a solar cell manufacturing method according to one embodiment of the present disclosure. As shown in FIG. 1, a substrate 100 having a first surface 110 and a second surface 120 facing each other is provided.

[0038] In another embodiment, in step S1, the material of the substrate 100 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material may be in a single crystalline state, a polycrystalline state, an amorphous state, or a microcrystalline state (a state having both single crystalline and amorphous states is called a microcrystalline state). For example, silicon may be at least one of single crystalline silicon, polysilicon, amorphous silicon, and microcrystalline silicon. In another embodiment, the material of the substrate 100 may be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanium, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride, copper indium selenium, and the like. In the following, the material of the substrate 100 will be described as silicon.

[0039] In step S2, FIG. 2 is a partial cross-sectional structural schematic diagram formed after performing a doping process on at least the first surface in a solar cell manufacturing method according to one embodiment of the present disclosure, and as shown in FIG. 2, a doping process is performed on at least the first surface 110 to form a doped layer 101 having a first doping element.

[0040] In step S3, Figure 3 is a schematic diagram of a partial cross-sectional structure formed after performing a first laser treatment in a solar cell manufacturing method according to one embodiment of the present disclosure, and as shown in Figures 2 and 3, a first laser treatment is performed on a portion of the doped layer 101 to form an activated portion 111, and the remaining doped layer 101 becomes a doped portion 121, and the doping concentration of the first doped element in the activated portion 111 is made lower than the doping concentration of the first doped element in the doped portion 121.

[0041] In step S4, FIG. 4 is a schematic diagram of a partial cross-sectional structure formed after a first etching process is performed in a solar cell manufacturing method according to one embodiment of the present disclosure, and as shown in FIGS. 3 and 4, a first etching process is performed on the first surface 110 using the doped portion 121 as a dead layer to remove the activated portion 111 and form a first textured surface 114.

[0042] In step S5, as shown in FIGS. 4 to 7, a doped polysilicon layer 102 containing a second doping element and a silicate glass layer 103 are sequentially formed at least on the side of the substrate 100 away from the doped portion 121.

[0043] 5 is a partial cross-sectional structural schematic diagram formed after an oxidation treatment is performed on at least the first surface in a solar cell manufacturing method according to one embodiment of the present disclosure, FIG. 6 is a partial cross-sectional structural schematic diagram formed after a polishing treatment is performed on the second surface based on the structure shown in FIG. 5, and FIG. 7 is a partial cross-sectional structural schematic diagram in which a doped polysilicon layer and a silicate glass layer are formed based on the structure shown in FIG. 6.

[0044] In step S6, FIG. 8 is a schematic diagram of a partial cross-sectional structure formed after performing a second laser treatment in a solar cell manufacturing method according to one embodiment of the present disclosure. As shown in FIG. 8, the second laser treatment is performed on at least a portion of the silicate glass layer 103 to form a sparse portion 113.

[0045] In step S7, as shown in Figures 8 to 11, a second etching process is performed on at least the second surface 120 using the remaining silicate glass layer 103 as a protective layer to remove the sparse portion 113 and the doped polysilicon layer 102 facing the sparse portion 113, thereby forming a second textured surface 115.

[0046] The first and second doping elements are of different types, and the first and second laser processes use different types of lasers.

[0047] 9 is a schematic diagram of a partial cross-sectional structure formed after etching is performed on the first surface based on the structure shown in FIG. 8, FIG. 10 is a schematic diagram of a partial cross-sectional structure formed after texturing is performed on the first and second surfaces based on the structure shown in FIG. 9, and FIG. 11 is a schematic diagram of a partial cross-sectional structure formed after cleaning is performed on the second surface based on the structure shown in FIG. 10.

[0048] The first laser treatment and the second laser treatment not only differ in the type of laser used, but also in the target.

[0049] Specifically, in step S3, the first laser treatment is performed on a portion of the doped layer 101, activating the portion of the doped layer 101, reducing the doping concentration of the first doping element in the portion of the doped layer 101, and improving the regularity of the crystal lattice in the portion of the doped layer 101, thereby converting the portion of the doped layer 101 into an activated portion 111, and the remaining portion of the doped layer 101 that has not been subjected to the first laser treatment becomes a doped portion 121. In other words, compared to the doped portion 121, the doping concentration of the doping element in the activated portion 111 is lower and the overall regularity of the crystal lattice in the activated portion 111 is higher, so the doped portion 121 is more likely to be etched under the same etching conditions.

[0050] Based on this, when the first etching process is then performed on the first surface 110 in step S4, the etching rate of the activated portion 111, which has a lower doping concentration of the first doping element, is much higher than that of the doped portion 121.As a result, the activated portion 111 can be removed to form the first textured surface 114, using the doped portion 121 as a dead layer, without providing a separate mask, which is advantageous for simplifying the manufacturing process of the solar cell. Furthermore, in a manufacturing method according to an embodiment of the present disclosure, a portion of the doped layer 101 is removed using a laser deposition process to form a selective emitter structure in which the doped layer 101 remains only in a portion of the first surface 110, i.e., compared to directly using a laser to ablate a portion of the doped layer 101, the combined action of the first laser treatment and the first etching treatment is advantageous in reducing damage to the first surface 110 caused by the laser. In other words, the laser used in the first laser treatment causes less damage to the first surface 110 than the laser used in the laser deposition process, thereby reducing the surface defect state density of the first surface 110 and advantageous in improving the photoelectric conversion efficiency of the solar cell that is finally formed.

[0051] After step S3, forming a selective emitter structure in which the doped layer 101, i.e., the doped portion 121, remains only in a portion of the first surface 110 is advantageous in reducing the contact resistance between the subsequently formed electrode and the doped portion 121, as well as reducing the probability of carrier recombination in other regions of the first surface 110, and ultimately improving the photoelectric conversion efficiency of the solar cell that is formed.

[0052] In step S6, the second laser treatment is performed on at least a portion of the silicate glass layer 103, modifying the portion of the silicate glass layer 103 into a sparse portion 113, for example, making the porosity of the sparse portion 113 higher than that of the remainder of the silicate glass layer 103. Based on this, when a second etching treatment is subsequently performed on at least the second surface 120 in step S7, the etching rate of the sparse portion 113, which has higher porosity, in the second etching treatment is much higher than that of the remainder of the silicate glass layer 103. As a result, the sparse portion 113 and the doped polysilicon layer 102 facing the sparse portion 113 can be removed to form the second textured surface 115 without providing a separate mask, using the remainder of the silicate glass layer 103 as a protective layer, which is advantageous for simplifying the manufacturing process of the solar cell.

[0053] Removing the doped polysilicon layer 102 facing the sparse portion 113 is advantageous in avoiding parasitic absorption of light by the removed portion of the doped polysilicon layer 102, and the exposed second textured surface 115 can improve the light absorption utilization rate and ensure low contact resistance between the subsequently formed electrode and the remaining doped polysilicon layer 102, which is also advantageous in improving the photoelectric conversion efficiency of the solar cell that is finally formed.

[0054] The purpose of the first laser treatment in step S3 is to activate a portion of the doped layer 101 and change the doping concentration of the first doping element in the portion of the doped layer 101 and the regularity of the crystal lattice in the portion of the doped layer 101, thereby converting the doped layer 101 with a reduced doping concentration of the first doping element into the activated portion 111. In contrast to this, the purpose of the second laser treatment in step S6 is to modify at least a portion of the silicate glass layer 103 and change the porosity of the portion of the silicate glass layer 103, thereby converting the portion of the silicate glass layer 103 with an increased porosity into the sparse portion 113.

[0055] In some cases, the doping concentration of the doping element in the activated portion 111 being lower than the doping concentration of the doping element in the doped portion 121 means that, when the surface of the activated portion 111 facing away from the substrate 100 is taken as a first reference plane and the surface of the doped portion 121 facing away from the substrate 100 is taken as a second reference plane, the effective doping concentration of the doping element in the activated portion 111 within a depth of 100 nm from the first reference plane toward the substrate 100 is lower than the effective doping concentration of the doping element in the doped portion 121 within a depth of 100 nm from the second reference plane toward the substrate 100, and the overall crystal lattice within the activated portion 111 is more regular.

[0056] In some examples, the doping concentration of the doping element in the active portion 111 is a first doping concentration, the doping concentration of the doping element in the doped portion 121 is a second doping concentration, and the ratio of the second doping concentration to the first doping concentration may be between 2 and 100, such as 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, or 195.

[0057] In some examples, the effective doping concentration of the activated portion 111 and the doped portion 121 was measured using an ECV (Electrochemical Capacitance-Voltage Profiler) measurement method, and the effective doping concentration of the doping element within the activated portion 111 at a depth of 100 nm from the first reference plane toward the substrate 100 was found to be 5×10 19 atom / cm 3 The effective doping concentration of the doping element within the doped portion 121 at a depth of 100 nm from the second reference plane toward the substrate 100 is less than 5×10 18 atom / cm 3 is greater than.

[0058] In addition, in the first etching process, treating the doped portion 121 and the activated portion 111 under the same etching conditions means that the doped portion 121 and the activated portion 111 are treated using the same etching solution and the treatment time for the doped portion 121 and the activated portion 111 is the same.

[0059] In other cases, when the same etching solution is used, the etching depth of the activated portion 111 by the etching solution per unit time is much greater than the etching depth of the doped portion 121, so the etching rate of the activated portion 111, which has a lower doping concentration of the first doping element, by the first etching process is much higher than that of the doped portion.

[0060] In another example, when the same etching solution is used, the ratio of the etching depth of the activated portion 111 to the etching depth of the doped portion 121 by the etching solution per unit time is 10 or more. In one example, when the activated portion 111 and the doped portion 121 are simultaneously etched using the same etching solution for about 600 seconds, the etching depth of the activated portion 111 is about 2 μm and the etching depth of the doped portion 121 is about 100 nm. In other words, it is considered that the doped portion 121 is hardly etched compared to the activated portion 111, and when the activated portion 111 is completely removed to form the first textured surface in the first etching process, at least most of the thickness of the doped portion 121 is not etched.

[0061] In other cases, a higher porosity in the loosened portion 113 compared to the remaining silicate glass layer 103 means that, from a microscopic perspective, a ruptured membrane is visible in the loosened portion 113, for example, cracks or fragments are visible in the loosened portion 113, with the maximum size of the fragments not exceeding 100 μm. The porosity of the loosened portion 113 from a microscopic perspective can be determined using a scanning electron microscope (SEM).

[0062] Each step in the method for manufacturing a solar cell according to an embodiment of the present disclosure will be described in detail below.

[0063] In another embodiment, the substrate 100 may be an N-type semiconductor substrate doped with an N-type doping element, where the first doping element is a P-type doping element and the second doping element is an N-type doping element. In another example, the N-type doping element may be at least one of a group V element, such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As), or the P-type semiconductor substrate is doped with a P-type doping element, where the P-type doping element may be at least one of a group III element, such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0064] In one example, in step S2, the doping process performed on at least the first surface 110 is a boron diffusion process, whereby at least a portion of the substrate 100 doped with boron (B) element can be regarded as a doped layer 101, and the doped layer 101 can be regarded as a boron diffusion layer; in step S4, the material of the doped polysilicon layer 102 can be N-type polysilicon, and the material of the silicate glass layer 103 can be phosphosilicate glass.

[0065] In another embodiment, the substrate may be a P-type semiconductor substrate doped with a P-type doping element, wherein the first doping element of the doped layer is an N-type doping element and the second doping element of the doped polysilicon layer is a P-type doping element.

[0066] In another embodiment, the solar cell is a single-sided cell, and in step S1, the first surface 110 can be considered as the front surface of the solar cell, i.e., the first surface 110 can function as a light-receiving surface for receiving incident light, and the second surface 120 can function as a backlight surface. In another embodiment, the solar cell is a double-sided cell, and both the first surface 110 and the second surface 120 can function as light-receiving surfaces for receiving incident light. As can be understood, the backlight surface described in one embodiment of the present disclosure can also receive incident light, but its light-receiving level is weaker than that of the light-receiving surface, and therefore it is defined as a backlight surface. Hereinafter, the first surface 110 will be described as the light-receiving surface and the second surface 120 as the backlight surface, as an example.

[0067] In another embodiment, as shown in Fig. 3, a red nanosecond laser, a green nanosecond laser, or a violet nanosecond laser may be used in the first laser treatment in step S3, and a violet picosecond laser, a green picosecond laser, a green femtosecond laser, or a violet femtosecond laser may be used in the second laser treatment in step S6, as shown in Fig. 8. In this manner, the doping concentration of the first doping element in a portion of the doped layer 101 is reduced by the red nanosecond laser, the green nanosecond laser, or the violet nanosecond laser, thereby forming the doped layer 101 with the reduced doping concentration of the first doping element as the activated portion 111, and improving the overall regularity of the crystal lattice in the activated portion 111. The porosity of a portion of the silicate glass layer 103 is changed by the violet picosecond laser, the green picosecond laser, the green femtosecond laser, or the violet femtosecond laser, thereby forming the silicate glass layer 103 with the increased porosity as the sparse portion 113.

[0068] It should be noted that the red nanosecond laser, green nanosecond laser, and violet nanosecond laser all belong to the nanosecond laser category, i.e., the laser used in the first laser process may be a short-pulse laser, the violet picosecond laser and green picosecond laser all belong to the picosecond laser category, the green femtosecond laser and violet femtosecond laser all belong to the femtosecond laser category, and the picosecond laser and femtosecond laser all belong to the ultrashort-pulse laser category, i.e., the laser used in the second laser process may be an ultrashort-pulse laser. In other words, the pulse width of the laser used in the first laser process is greater than the pulse width of the laser used in the second laser process.

[0069] In other examples, the wavelength range of the red nanosecond laser used in the first laser treatment may be 700 nm to 1500 nm, such as 730 nm, 750 nm, 780 nm, 800 nm, 820 nm, 850 nm, 880 nm, 900 nm, 930 nm, 950 nm, 960 nm, 1000 nm, 1020 nm, 1050 nm, 1060 nm, 1200 nm, 1230 nm, 1250 nm, 1270 nm, 1300 nm, 1320 nm, 1350 nm, 1370 nm, 1420 nm, 1450 nm, or 1480 nm.

[0070] In other examples, the wavelength range of the green nanosecond laser used in the first laser treatment and the green picosecond laser and green femtosecond laser used in the second laser treatment may all be 492 nm to 577 nm, for example, 493 nm, 495 nm, 496 nm, 500 nm, 502 nm, 505 nm, 508 nm, 510 nm, 513 nm, 515 nm, 516 nm, 520 nm, 522 nm, 525 nm, 528 nm, 530 nm, 532 nm, 535 nm, 538 nm, 540 nm, 542 nm, 545 nm, 548 nm, 550 nm, 552 nm, 555 nm, 558 nm, 560 nm, 562 nm, 565 nm, 568 nm, 570 nm, 572 nm, 575 nm, or 578 nm.

[0071] In another example, the wavelength range of the violet nanosecond laser used in the first laser treatment and the violet picosecond laser and violet femtosecond laser used in the second laser treatment may all be 200 nm to 400 nm, for example, 205 nm, 210 nm, 215 nm, 220 nm, 225 nm, 230 nm, 235 nm, 240 nm, 245 nm, 250 nm, 255 nm, 260 nm, 26 ... m, 265 nm, 270 nm, 275 nm, 280 nm, 285 nm, 290 nm, 295 nm, 300 nm, 305 nm, 310 nm, 315 nm, 320 nm, 325 nm, 330 nm, 335 nm, 340 nm, 345 nm, 350 nm, 355 nm, 360 nm, 365 nm, 370 nm, 375 nm, 380 nm, 385 nm, 390 nm, or 395 nm, etc.

[0072] In another embodiment, as shown in FIGS. 3 and 4, in step S4, forming the first textured surface 114 may include forming the first groove 104 whose bottom surface is the first textured surface 114.

[0073] It should be noted that the etching rate for the activated portion 111 in the first etching process is much higher than the etching rate for the doped portion 121. Based on this, if the doped portion 121 is treated as a dead layer in step S4, not only can the activated portion 111 be removed, but the first surface 110 exposed after the activated portion 111 is removed can also be further etched to form the first groove 104, which is recessed further into the substrate 100 relative to the portion of the substrate 100 facing the doped portion 121, i.e., recessed in the direction from the first surface 110 toward the second surface 120. In other words, the first surface 110 includes first laser regions 140 and first non-laser regions 150 alternately arranged along the first direction X, the doped portions 121 not etched by the first etching process are located in the first non-laser regions 150, and the first grooves 104 are located in the first laser regions 140. After performing step S4, the surface of the substrate 100 located in the first non-laser regions 150 is higher than the surface of the substrate 100 located in the first laser regions 140, thereby forming the first grooves 104 in the first laser regions 140. In addition, by further etching the substrate 100 facing the activated portions 111 based on the first etching process, a first textured surface 114 can be formed on at least the bottom surfaces of the first grooves 104.

[0074] Thus, on the one hand, the first textured surface 114 not only reduces the reflectance of the bottom surface of the first grooves 104 but also forms light traps and improves the absorption effect of the first textured surface 114 of incident light, and on the other hand, since the first grooves 104 are recessed into the substrate 100, light incident into the first grooves 104 is less likely to be reflected out of the solar cell, further improving the absorption and utilization rate of the incident light by the first grooves 104. Therefore, the cooperation between the first grooves 104 and the first textured surface 114 is advantageous for improving the photoelectric conversion efficiency of the solar cell.

[0075] Furthermore, by controlling the concentration of the etching solution used in the first etching process and / or the processing time of the first etching process, it is possible to control whether the first etching process further etches the first surface 110 exposed after the activation portion 111 is removed, i.e., it is possible to control whether the first groove 104 is further formed in the first laser region 140 of the substrate 100, and further, it is possible to control the degree of etching of the substrate 100 opposite the activation portion 111 by the first etching process, i.e., it is possible to control the depth of the first groove 104 formed.

[0076] In other examples, the processing time of the first etching process may be 600 s to 750 s, such as 610 s, 620 s, 630 s, 640 s, 650 s, 660 s, 670 s, 680 s, 690 s, 700 s, 710 s, 720 s, 730 s, or 740 s.

[0077] In other examples, the depth of the first groove 104 may be between 2.5 μm and 4 μm, such as 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 3.6 μm, 3.7 μm, 3.8 μm, or 3.9 μm.

[0078] Although FIG. 4 illustrates an example in which the doped portion 121 is left in the first non-laser region 150 of the substrate 100 and the first groove 104 is formed in the first laser region 140 of the substrate 100, in actual applications, the surfaces of the first non-laser region and the first laser region of the substrate may be maintained flat.

[0079] In another embodiment, as shown in FIGS. 8 to 11, in step S7, the step of forming the second textured surface 115 may include the step of forming the second groove 105 whose bottom surface is the second textured surface 115.

[0080] It should be noted that the etching rate of the sparse portions 113 in the second etching process is much higher than the etching rate of the remaining silicate glass layer 103. Based on this, if the remaining silicate glass layer 103 is used as a protective layer in step S7, not only can the sparse portions 113 be removed, but the second surface 120 exposed after the sparse portions 113 are removed can also be further etched to form second grooves 105, which are recessed further into the substrate 100 relative to the portion of the substrate 100 facing the sparse portions 113, i.e., recessed in the direction from the second surface 120 toward the first surface 110. In other words, the second surface 120 includes second laser regions 160 and second non-laser regions 170 alternately arranged along the first direction X, the silicate glass layer 103 not etched by the second etching process is located in the second non-laser regions 170, and the second grooves 105 are located in the second laser regions 160. After performing step S7, the surface of the substrate 100 located in the second non-laser regions 170 is higher than the surface of the substrate 100 located in the second laser regions 160, thereby forming the second grooves 105 in the second laser regions 160. In addition, by further etching the substrate 100 opposite the sparse portions 113 based on the second etching process, a second textured surface 115 can be formed on at least the bottom surfaces of the second grooves 105.

[0081] Thus, on the one hand, the second textured surface 115 not only reduces the reflectance of the bottom surface of the second grooves 105 but also forms light traps, improving the effect of the second textured surface 115 in absorbing incident light, and on the other hand, since the second grooves 105 are recessed into the substrate 100, light incident into the second grooves 105 is less likely to be reflected out of the solar cell, further improving the absorption and utilization rate of the incident light by the second grooves 105. Therefore, the cooperation between the second grooves 105 and the second textured surface 115 is advantageous in improving the photoelectric conversion efficiency of the solar cell.

[0082] Furthermore, by controlling the concentration of the etching solution used in the second etching process and / or the processing time of the second etching process, it is possible to control whether the second etching process further etches the second surface 120 exposed after removing the sparse portion 113, i.e., it is possible to control whether a second groove 105 is further formed in the second laser region 160 of the substrate 100, and further to control the degree of etching of the substrate 100 opposite the sparse portion 113 by the second etching process, i.e., it is possible to control the depth of the second groove 105 formed.

[0083] In other examples, the processing time of the second etching process may be 600 s to 750 s, such as 610 s, 620 s, 630 s, 640 s, 650 s, 660 s, 670 s, 680 s, 690 s, 700 s, 710 s, 720 s, 730 s, or 740 s.

[0084] In other examples, the depth of the second groove 105 may be between 2 μm and 3 μm, such as 2.1 μm, 2.2 μm, 2.3 μm, 2.4 μm, 2.5 μm, 2.6 μm, 2.7 μm, 2.8 μm, or 2.9 μm.

[0085] Although FIG. 10 illustrates an example in which the silicate glass layer 103 is left in the second non-laser region 170 of the substrate 100 and the second groove 105 is formed in the second laser region 160 of the substrate 100, in actual applications, the surfaces of the second non-laser region and the second laser region of the substrate may be kept flat.

[0086] Furthermore, after forming the first groove 104 having the first textured surface 114 at the bottom in step S4, the second groove 105 having the second textured surface 115 at the bottom can be formed in step S7. In other words, the first surface 110 may have the first groove 104 and the second surface 120 may have the second groove 105 at the same time in the solar cell that is finally formed. In this way, it is advantageous to improve both the absorption and utilization rate of incident light by the first surface 110 and the absorption and utilization rate of incident light by the second surface 120, thereby improving the double-sidedness of the solar cell.

[0087] In practical applications, when a first groove having a first textured bottom surface is formed in step S4, a second textured bottom surface can be formed in step S7 that is flush with the surface of the substrate facing the remaining silicate glass layer; when a first textured bottom surface is formed in step S4 that is flush with the surface of the substrate facing the doped portion, a second groove having a second textured bottom surface can be formed in step S7; or when a first textured bottom surface is formed in step S4 that is flush with the surface of the substrate facing the doped portion, a second textured bottom surface can be formed in step S7. Note that "flush" above means that the difference in height between the two surfaces is very small, even zero.

[0088] In another embodiment, as shown in FIGS. 2 and 3, in the step S3 of performing the first laser treatment, an oxide layer (not shown) may be formed on the doped layer 101, and as shown in FIGS. 3 and 4, in the step S4 of performing the first etching treatment on the first surface 110, the step of etching the first surface 110 using a first chain hydrofluoric acid process to remove the oxide layer, and the step of etching the first surface 110 using a first texturing process to remove the activated portion 111 and form a first textured surface 114.

[0089] It should be noted that, based on the action of the laser used in the first laser treatment on the doped layer 101, the surface of the doped layer 101 that faces away from the substrate 100 is easily oxidized by heat, thereby forming an oxide layer on the doped layer 101. In another example, the material of the oxide layer may be silicon oxide.

[0090] Based on this, the first etching process includes two etching steps, first etching the first surface 110 using a first sequence hydrofluoric acid process and then etching the first surface 110 using a first texturing process, thereby targeting and removing the oxide layer and the activated portion 111, respectively, which is advantageous for improving the etching accuracy of the first etching process. In another example, in step S4, it is necessary to finally form the first groove 104 whose bottom surface is the first textured surface 114. Designing the first etching process to include two etching steps is advantageous for forming a good step shape on the first surface 110, i.e., for forming the first groove 104 with a controllable surface shape, for example, for forming the first groove 104 with approximately the same depth in each region.

[0091] In another embodiment, performing a first etching process on the first surface includes etching the first surface using a first texturing process to remove the activated portions and form the first textured surface. In other words, the first etching process may be a first texturing process, i.e., directly using the first texturing process to remove the oxide layer and the activated portions and form the first textured surface.

[0092] In another embodiment, the first surface 110 includes first laser regions 140 and first non-laser regions 150 alternately arranged along the first direction X, and the second surface 120 includes second laser regions 160 and second non-laser regions 170 alternately arranged along the first direction X. After performing step S4 to form the first textured surface 114, the first surface 110 located at the first non-laser regions 150 is still the third textured surface 130 (see FIG. 1 ), where the third textured surface 130 has a third pyramid structure and the first textured surface 114 has a first pyramid structure, and the size of the third pyramid structure is larger than the size of the first pyramid structure.

[0093] Note that the entire surface of the first surface 110 of the substrate 100 provided in step S1 may be the third texture surface 130, and after steps S2 to S4 are performed, the substrate 100 is etched by the first etching process, i.e., the third texture surface 130 located in the first laser region 140 is further etched, thereby converting the third texture surface 130 located in the first laser region 140 into the first texture surface 114. In this way, the smaller first pyramid structure is advantageous for improving the light trapping effect of the first texture surface 114.

[0094] In another embodiment, as shown in FIGS. 1 and 2, the first surface 110 and the second surface 120 provided in step S1 may both be the third textured surface 130. As shown in FIGS. 4 to 6, after forming the first textured surface 114 in step S4 and before forming the doped polysilicon layer 102 in step S5, the manufacturing method may further include a step of performing a polishing process on the second surface 120 to form a polished surface. As shown in FIGS. 6 and 7, the step of forming the doped polysilicon layer 102 and the silicate glass layer 103 includes a step of forming the doped polysilicon layer 102 on the polished surface and forming the silicate glass layer 103 on the side of the doped polysilicon layer 102 away from the polished surface.

[0095] Furthermore, since the polished surface has a high flatness, forming the doped polysilicon layer 102 on the polished surface is advantageous for improving the uniformity of the doped polysilicon layer 102. In other words, forming the doped polysilicon layer 102 with approximately the same thickness in each region is advantageous for improving the passivation effect of the doped polysilicon layer 102 on the surface of the substrate 100, and for improving the photoelectric conversion efficiency of the solar cell that is ultimately formed.

[0096] In other cases, as shown in FIG. 2, in the step of performing a doping treatment on at least the first surface 110 in step S2, a doping treatment is further performed on the second surface 120 to form a second doped layer 108 having a first doping element on the second surface 120, and the doped layer 101 formed on the first surface 110 can be considered as the first doped layer, and as shown in FIGS. 4 to 6, in the step of performing a polishing treatment on the second surface 120, the second doped layer 108 is removed.

[0097] In other cases, as shown in FIG. 5, after forming the first textured surface 114 in step S4 and before forming the polished surface, the manufacturing method may further include the step of performing an oxidation treatment on at least the first surface 110 to form a first diffusion barrier layer 116 on the doped portion 121 and a second diffusion barrier layer 126 on the first textured surface 114.

[0098] It should be noted that the first diffusion barrier layer 116 is formed after a portion of the thickness of the doped portion 121 has been oxidized, and in other examples, the material of the first diffusion barrier layer 116 may be borosilicate glass, and the second diffusion barrier layer 126 is formed after a portion of the thickness of the substrate 100 has been oxidized, and in other examples, the material of the second diffusion barrier layer 126 may be silicon oxide.

[0099] Furthermore, in the step of performing an oxidation treatment on at least the first surface 110, further diffusion of the doped element in the doped portion 121 into the substrate 100 is promoted, which is advantageous for deepening the junction depth of the doped portion 121 and deepening the junction depth of the PN junction formed by both the doped portion 121 and the substrate 100, and for slightly reducing the doping concentration of the doped element in the doped portion 121, which reduces the defect level density at the contact point between the electrode to be formed subsequently and the doped portion 121, and improves the contact performance between the electrode and the doped portion 121. Based on this, as shown in FIG. 7 , the step of forming the doped polysilicon layer 102 and the silicate glass layer 103 in step S5 may further include forming the doped polysilicon layer 102 on both the first diffusion barrier layer 116 and the second diffusion barrier layer 126, and forming the silicate glass layer 103 on both sides of the doped polysilicon layer 102 away from the first diffusion barrier layer 116 and the second diffusion barrier layer 126. It should be noted that, during the step of forming the doped polysilicon layer 102 and the silicate glass layer 103, the second doping element gradually diffuses into the doped polysilicon layer 102 due to the effect of high temperature. Thus, on the one hand, the first diffusion barrier layer 116 located in the doped portion 121 is advantageous in preventing further diffusion of the second doping element into the doped portion 121, avoiding loss of the second doping element and preventing the doped portion 121 from being modified due to the effect of the diffusion of the second doping element, for example, preventing the doped portion 121 from being converted from P-type to N-type; on the other hand, the second diffusion barrier layer 126 located on the first textured surface 114 is advantageous in preventing further diffusion of the second doping element into the substrate 100, for example, into the first laser region 140, avoiding loss of the second doping element.

[0100] In another case, after forming the first textured surface in step S4 and before forming the polished surface, the manufacturing method may further include performing an oxidation treatment on at least the first surface to form a first diffusion barrier layer in the doped portion and a second diffusion barrier layer on the first textured surface, the surface formed by both the first diffusion barrier layer and the second diffusion barrier layer includes an edge region and a central region surrounded by the edge region, and the step of forming the doped polysilicon layer and the silicate glass layer may further include forming the doped polysilicon layer in the edge region and forming the silicate glass layer on a side of the doped polysilicon layer away from the edge region. In other words, in the step of forming the doped polysilicon layer and the silicate glass layer on the second surface in step S5, the doped polysilicon layer and the silicate glass layer are sequentially formed also in the edge region of the surface formed by both the first diffusion barrier layer and the second diffusion barrier layer by wraparound plating. In this way, the first diffusion barrier layer located in the doped portion is also advantageous in preventing further diffusion of the second doping element into the doped portion, and the second diffusion barrier layer located on the first textured surface is also advantageous in preventing further diffusion of the second doping element into the substrate.

[0101] In another example, as shown in FIG. 2 , in step S2, a second doped layer 108 having the first doping element is further formed on the second surface 120. Based on this, as shown in FIG. 5 , in the step of performing an oxidation treatment on at least the first surface 110, the second doped layer 108 is further oxidized to form a third diffusion barrier layer 136 on the side of the second doped layer 108 away from the second surface 120. Note that the second diffusion barrier layer 126 and the third diffusion barrier layer 136 may be formed simultaneously by the same oxidation treatment step. In another example, the material of the third diffusion barrier layer 136 and the material of the second diffusion barrier layer 126 may both be silicon oxide. Furthermore, in the step of performing a polishing treatment on the second surface 120, not only the second doped layer 108 but also the third diffusion barrier layer 136 are removed.

[0102] In other cases, in the oxidation treatment step, the temperature may be controlled to 1000°C to 1100°C, for example, 1010°C, 1020°C, 1030°C, 1040°C, 1050°C, 1060°C, 1070°C, 1080°C, or 1090°C.

[0103] In other cases, as shown in FIG. 7, the step of forming the doped polysilicon layer 102 and the silicate glass layer 103 may include, after performing step S4, forming a semiconductor layer (not shown) on the first surface 110 and the second surface 120, forming a doped source layer (not shown) having a second doping element on the side of the semiconductor layer away from the substrate 100, and performing a high-temperature treatment on the semiconductor layer and the doped source layer to promote diffusion of the second doping element into the semiconductor layer, thereby converting the semiconductor layer into the doped polysilicon layer 102 and converting the doped source layer into the silicate glass layer 103. In other cases, the step of forming the doped polysilicon layer and the silicate glass layer may include the steps of forming a semiconductor layer (not shown) on the second surface 120 after performing step S4, forming a semiconductor layer also in the edge region of the surface formed by both the first diffusion barrier layer and the second diffusion barrier layer by wraparound plating, forming a doped source layer (not shown) having a second doping element on the side of the semiconductor layer away from the substrate, and performing a high-temperature treatment on the semiconductor layer and the doped source layer to promote diffusion of the second doping element into the semiconductor layer, thereby converting the semiconductor layer into a doped polysilicon layer and converting the doped source layer into a silicate glass layer.

[0104] In other instances, the material of the semiconductor layer may be amorphous silicon, and a high temperature processing step may facilitate crystallizing and converting the amorphous silicon to polysilicon, and in other instances, the material of the semiconductor layer may be polysilicon.

[0105] 1 , the first surface 110 includes first laser regions 140 and first non-laser regions 150 alternately arranged along the first direction X, and the second surface 120 includes second laser regions 160 and second non-laser regions 170 alternately arranged along the first direction X. As shown in FIG. 3 , performing a first laser treatment on a portion of the doped layer 101 in step S3 may include performing a first laser treatment on the doped layer 101 located in the first laser region 140 to form an activated portion 111 located in the first laser region 140. As shown in FIG. 8 , performing a second laser treatment on at least a portion of the silicate glass layer 103 may include performing a second laser treatment on the silicate glass layer 103 located in the second laser region 160 to form a sparse portion 113 located in the second laser region 160.

[0106] In this way, in the finally formed solar cell, the doped portion 121 is located only in the first non-laser region 150, and the doped portion 121 can be regarded as a selective emitter located on the first surface 110, which ensures that subsequent electrodes have good current collection efficiency based on the doped portion 121, and also prevents the first laser region 140 from being covered by the doped layer 101, thereby avoiding parasitic absorption of light incident on the first laser region 140 by the doped layer 101, improving the utilization rate of the incident light by the first surface 110, and advantageously improving the photoelectric conversion efficiency of the solar cell.

[0107] 7, in the step of forming the doped polysilicon layer 102 having the second doping element in step S5, a tunnel layer (not shown) is further formed between the second surface 120 and the doped polysilicon layer 102. In another example, the material of the tunnel layer is silicon oxide. Based on this, in step S7, a second etching process further removes the tunnel layer facing the sparse portion 113.

[0108] In this way, in the finally formed solar cell, the tunnel layer and the doped polysilicon layer 102 are located only in the second non-laser region 170, and the tunnel layer and the doped polysilicon layer 102 form a selective passivation contact structure on the second surface 120, ensuring that the tunnel layer and the doped polysilicon layer 102 have a good passivation effect on the second surface 120 and preventing the second laser region 160 from being covered by the doped polysilicon layer 102. This prevents the doped polysilicon layer 102 from parasitic absorption of light incident on the second laser region 160, and is advantageous to improving the utilization rate of, for example, incident light by the second surface 120 and improving the photoelectric conversion efficiency of the solar cell.

[0109] In another embodiment, as shown in FIG. 10 or 11 , the first non-laser region 150 and the second non-laser region 170 both include at least the area where the orthogonal projection of an electrode (not shown) onto the substrate 100 is located. The area on the first surface 110 other than the first non-laser region 150 is the first laser region 140, and the area on the second surface 120 other than the second non-laser region 170 is the second laser region 160. To ensure that the film layer in contact with the electrode has a high doping concentration or that the areas in contact with the electrode are both high-concentration regions and to reduce contact resistance, the orthogonal projection areas of the first non-laser region 150 and the second non-laser region 170 are generally set to be equal to or larger than the orthogonal projection area of ​​the electrode. In other words, the orthogonal projection area of ​​the electrode onto the substrate 100 is smaller than the area of ​​the first non-laser region or the second non-laser region, and the orthogonal projection position is necessarily within the first non-laser region or the second non-laser region.

[0110] The number of laser regions and the number of non-laser regions may both be plural, and the laser regions and non-laser regions may be alternately arranged along the fixed direction. In other words, the laser regions may be located between adjacent non-laser regions, and the non-laser regions may be located between adjacent laser regions. The laser regions include a first laser region 140 and a second laser region 160, and the non-laser regions include a first non-laser region 150 and a second non-laser region 170.

[0111] In other embodiments, as shown in FIG. 10 or FIG. 11 , the orthogonal projection area of ​​the first laser region 140 onto the substrate 100 and the orthogonal projection area of ​​the second laser region 160 onto the substrate 100 may be different. Furthermore, depending on the type of solar cell, the difference in the light absorption rate of the first surface 110 and the second surface 120, and the design of the size of the subsequently formed doped portion 121 and doped polysilicon layer 102, the orthogonal projection area of ​​the first laser region 140 onto the first surface 110 and the orthogonal projection area of ​​the second laser region 160 onto the first surface 110 may be different, i.e., the size of the first laser region 140 and the size of the second laser region 160 may be different. Thus, the manufacturing method according to one embodiment of the present disclosure is applicable to multiple solar cells.

[0112] In one example, the orthogonal projection area of ​​the first laser region on the first surface may be equal to or smaller than the orthogonal projection area of ​​the second laser region on the first surface, and in another example, the orthogonal projection area of ​​the first laser region on the first surface may be greater than the orthogonal projection area of ​​the second laser region on the first surface. Note that the orthogonal projection areas of the multiple first laser regions on the first surface may be the same or different and can be designed according to actual needs, and the orthogonal projection areas of the multiple second laser regions on the first surface may be the same or different and can be designed according to actual needs.

[0113] In another embodiment, the orthogonal projection of the first laser region onto the first surface does not overlap with the orthogonal projection of the second laser region onto the first surface, in other words, the first laser region and the second laser region are prevented from facing each other along the second direction, which is the thickness direction of the solar cell, and thus the laser acting on the first surface in the first laser treatment in step S3 and the laser acting on the second surface in the second laser treatment in step S6 are prevented from repeatedly treating the same portion of the substrate, which is advantageous in avoiding damage caused by repeated local overheating of the substrate and thereby improving the electrical performance of the finally formed solar cell.

[0114] In one example, the first laser region and the second non-laser region may be opposed along the second direction, i.e., the orthogonal projection of the first laser region onto the first surface may overlap with the orthogonal projection of the second non-laser region onto the first surface, and the first non-laser region and the second laser region may be opposed along the second direction, i.e., the orthogonal projection of the first non-laser region onto the first surface may overlap with the orthogonal projection of the second laser region onto the first surface.

[0115] In other embodiments, the orthogonal projection of the first laser region onto the first surface may at least partially overlap with the orthogonal projection of the second laser region onto the first surface.

[0116] In actual applications, it is possible that the orthogonal projection area of ​​the first laser region on the first surface is different from the orthogonal projection area of ​​the second laser region on the first surface, and that the orthogonal projection area of ​​the first laser region on the first surface does not overlap with the orthogonal projection area of ​​the second laser region on the first surface, may occur simultaneously on the same solar cell; alternatively, it is possible that the orthogonal projection area of ​​the first laser region on the first surface is different from the orthogonal projection area of ​​the second laser region on the first surface, and that the orthogonal projection area of ​​the first laser region on the first surface at least partially overlap with the orthogonal projection area of ​​the second laser region on the first surface.

[0117] In another embodiment, as shown in Figures 9 and 10, the step of performing a second etching process on at least the second surface 120 includes the steps of: etching the first surface 110 using a second chain hydrofluoric acid process to remove the silicate glass layer 103 located on the first surface 110; and etching the first surface 110 and the second surface 120 using a second texturing process to remove the doped polysilicon layer 102, the first diffusion barrier layer 116, and the second diffusion barrier layer 126 located on the first surface 110 to expose the first textured surface 114 and the doped portion 121, and removing the sparse portion 113 and the doped polysilicon layer 102 located in the second laser region 160 to form the second textured surface 115.

[0118] In step S6, the second laser treatment is performed only on a portion of the silicate glass layer 103 formed on the second surface 120 to form the sparse portion 113, and the laser treatment is not performed on the silicate glass layer 103 formed on the first surface 110.In other words, the porosity of the remaining silicate glass layer 103 located on the second surface 120 and the porosity of the silicate glass layer 103 located on the first surface 110 are not modified by the second laser treatment, and both are lower than the porosity of the sparse portion 113.

[0119] Based on this, the second etching process includes two etching steps, first etching the first surface 110 using a second chain hydrofluoric acid process to remove the silicate glass layer 103 located on the first surface 110, which is advantageous in avoiding the phenomenon that the subsequent second texturing process is blocked by the silicate glass layer 103 located on the first surface 110 and therefore cannot remove the doped polysilicon layer 102 located on the first surface 110. Next, using the remaining silicate glass layer 103 located on the second surface 120 as a protective layer, the first surface 110 and the second surface 120 are etched using a second texturing process to remove the doped polysilicon layer 102, the first diffusion barrier layer 116, and the second diffusion barrier layer 126 located on the first surface 110, and also remove the sparse portion 113 and the doped polysilicon layer 102 located in the second laser region 160. This reduces the number of film layers to be removed on the first surface 110 and the second surface 120 by the second texturing process to two, which is advantageous for improving the etching accuracy of the second etching process. In another example, in step S7, a second groove 105 having a second textured surface 115 at its bottom surface needs to be finally formed. Designing the second etching process to include two etching steps is advantageous for forming a good step shape on the second surface 120, i.e., for forming a second groove 105 with a controllable surface shape, for example, for forming a second groove 105 with approximately the same depth in each region.

[0120] In another embodiment, as shown in FIGS. 10 and 11 , after performing the second texturing process, the manufacturing method may further include cleaning the second surface 120 using an acid cleaning process to remove the silicate glass layer 103 located in the second non-laser region 170 and expose the doped polysilicon layer 102 located in the second non-laser region 170.

[0121] In summary, the first laser treatment is used to increase the doping concentration of the first doping element in the portion of the doped layer 101. When the first etching treatment is then performed on the first surface 110 based on this, the etching rate of the activated portion 111, which has a lower doping concentration of the first doping element, is much higher than that of the doped portion 121. This allows the activated portion 111 to be removed without providing a separate mask, using the doped portion 121 as a dead layer, to form the first textured surface 114, which is advantageous for simplifying the solar cell manufacturing process. Furthermore, compared to removing the portion of the doped layer 101 using a laser deposition process, the combined effect of the first laser treatment and the first etching treatment is advantageous for reducing damage to the first surface 110 caused by the laser. Furthermore, forming a selective emitter structure in which the doped portion 121 remains only in a portion of the first surface 110 is advantageous in reducing the contact resistance between the subsequently formed electrode and the doped portion 121, as well as reducing the probability of carrier recombination in other regions of the first surface 110.

[0122] The second laser treatment is used to modify the portion of the silicate glass layer 103 into the sparse portion 113. When a second etching process is subsequently performed on at least the second surface 120 based on this, the etching rate of the sparse portion 113, which has higher porosity, is much higher than that of the remaining silicate glass layer 103. This allows the sparse portion 113 and the doped polysilicon layer 102 facing the sparse portion 113 to be removed to form the second textured surface 115 without providing a separate mask, using the remaining silicate glass layer 103 as a protective layer, which is advantageous for simplifying the solar cell manufacturing process. Removing the doped polysilicon layer 102 facing the sparse portion 113 is advantageous for avoiding parasitic light absorption by the removed portion of the doped polysilicon layer 102. The exposed second textured surface 115 improves light absorption and utilization, and is also advantageous for ensuring low contact resistance between a subsequently formed electrode and the remaining doped polysilicon layer 102.

[0123] In another embodiment of the present disclosure, a solar cell is provided that is manufactured by the manufacturing method according to the aforementioned embodiment. Hereinafter, the solar cell according to the another embodiment of the present disclosure will be described in detail with reference to the drawings. Note that a description of the same or corresponding parts as those in the aforementioned embodiment will be omitted.

[0124] The solar cell includes a solar cell formed by the manufacturing method according to the above-described embodiment.

[0125] The solar cell may be a cell having a passivation structure, such as a TOPCON cell, a PERC cell, or a heterojunction cell. A solar cell is formed by the manufacturing method according to the above-described embodiment, and then, by performing two different laser processes, a first laser process and a second laser process, without providing a separate mask, to form a doped portion 121 located only in a partial region of the first surface 110 and a doped polysilicon layer 102 located only in a partial region of the second surface 120. This exposes the first textured surface 114 on the first surface 110 and the second textured surface 115 on the second surface 120, thereby improving the utilization rate of incident light through the first surface 110 and the second surface 120, and advantageously improving the photoelectric conversion efficiency of the solar cell thus formed.

[0126] In another embodiment, as shown in FIG. 11 , a solar cell includes a substrate 100 having a first surface 110 and a second surface 120 facing each other, where the first surface 110 includes first laser regions 140 and first non-laser regions 150 alternately arranged along a first direction X, and the second surface 120 includes second laser regions 160 and second non-laser regions 170 alternately arranged along the first direction X, a doped portion 121 located in the first non-laser region 150, a doped polysilicon layer 102 located in the second non-laser region 170, a first groove 104 in the first laser region 140, the bottom surface of which is a first textured surface 114, and a second groove 105 in the second laser region 160, the bottom surface of which is a second textured surface 115.

[0127] As described above, on the one hand, the first textured surface 114 can enhance the absorption effect of incident light. Since the first grooves 104 are recessed into the substrate 100, light incident into the first grooves 104 is less likely to be reflected out of the solar cell, further improving the absorption and utilization rate of the incident light by the first grooves 104. Therefore, the cooperation of the first grooves 104 and the first textured surface 114 is advantageous for improving the absorption and utilization rate of the incident light by the first surface 110. On the other hand, the second textured surface 115 can enhance the absorption effect of incident light. Since the second grooves 105 are recessed into the substrate 100, light incident into the second grooves 105 is less likely to be reflected out of the solar cell, further improving the absorption and utilization rate of the incident light by the second grooves 105. Therefore, the cooperation of the second grooves 105 and the second textured surface 115 is advantageous for improving the absorption and utilization rate of the incident light by the second surface 120. This multifaceted cooperation is advantageous for improving the photoelectric conversion efficiency of the solar cell.

[0128] In other cases, the depth of the first grooves 104 is greater than the depth of the second grooves 105 along the second direction Y. In other examples, the depth of the first grooves 104 may be 2.5 μm to 4 μm, and the depth of the second grooves 105 may be 2 μm to 3 μm.

[0129] In other embodiments, the solar cell may further include a tunnel layer located between the second surface 120 and the doped polysilicon layer 102 and forming a selective passivation contact structure with the doped polysilicon layer 102 to the second surface 120.

[0130] Those skilled in the art will understand that the above embodiments are specific examples for realizing the present disclosure, and that various changes in form and details can be made in actual applications without departing from the spirit and scope of the embodiments of the present disclosure. Since those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure, the scope of protection of the embodiments of the present disclosure should be based on the content limited by the claims. [Explanation of symbols]

[0131] 100 boards 110 Page 1 120 Side 2 130 Third Texture Plane 140 First Laser Region 150 First Non-Laser Region 160 Second Laser Region 170 Second Non-Laser Region 101 doped layer 111 Activation part 121 Dope Section 102 doped polysilicon layer 103 Silicate Glass Layer 113 Sparse area 104 First groove 114 First Texture Surface 105 Second groove 115 Second Texture Surface 116 First diffusion barrier layer 126 Second diffusion barrier layer 136 Third diffusion barrier layer 108 Second doped layer

Claims

1. providing a substrate having opposing first and second surfaces; doping at least the first surface to form a doped layer having a first doping element; performing a first laser treatment on a part of the doped layer to form an activated portion, and forming the remaining doped layer as a doped portion, and making the doping concentration of the first doping element in the activated portion lower than the doping concentration of the first doping element in the doped portion; performing a first etching process on the first surface using the doped portion as a dead layer to remove the activated portion and form a first textured surface; forming, sequentially, at least on a side of the substrate away from the doped portion, a doped polysilicon layer having a second doping element and a silicate glass layer; performing a second laser treatment on at least a portion of the silicate glass layer to form a loose portion; performing a second etching process on at least the second surface using the remaining silicate glass layer as a protection layer to remove the rough portion and the doped polysilicon layer facing the rough portion, thereby forming a second textured surface; the first doping element and the second doping element are of different types; The first laser treatment and the second laser treatment use different laser types. A method for manufacturing a solar cell comprising the steps of:

2. the first surface and the second surface are both third texture surfaces, After forming the first textured surface and before forming the doped polysilicon layer, further comprising a step of performing a polishing process on the second surface to form a polished surface; forming the doped polysilicon layer and the silicate glass layer; forming the doped polysilicon layer on the polishing surface and forming the silicate glass layer on a side of the doped polysilicon layer away from the polishing surface; The method for manufacturing a solar cell according to claim 1 .

3. After forming the first textured surface and before forming the polished surface, performing an oxidation treatment on at least the first surface to form a first diffusion barrier layer on the doped portion and a second diffusion barrier layer on the first textured surface; forming the doped polysilicon layer and the silicate glass layer; forming the doped polysilicon layer on both the first diffusion barrier layer and the second diffusion barrier layer, and forming the silicate glass layer on both sides of the doped polysilicon layer away from the first diffusion barrier layer and the second diffusion barrier layer. The method for manufacturing a solar cell according to claim 2 .

4. After forming the first textured surface and before forming the polished surface, performing an oxidation treatment on at least the first surface to form a first diffusion barrier layer on the doped portion and a second diffusion barrier layer on the first textured surface; a surface formed by both the first diffusion barrier layer and the second diffusion barrier layer includes an edge region and a central region surrounded by the edge region; forming the doped polysilicon layer and the silicate glass layer; forming the doped polysilicon layer in the edge region and forming the silicate glass layer on a side of the doped polysilicon layer away from the edge region. The method for manufacturing a solar cell according to claim 2 .

5. the first surface includes first laser regions and first non-laser regions alternately arranged along a first direction; the second surface includes second laser regions and second non-laser regions alternately arranged along the first direction, The step of performing the first laser treatment on a portion of the doped layer includes: performing the first laser treatment on the doped layer located in the first laser region to form the active portion located in the first laser region; The step of performing the second laser treatment on at least a portion of the silicate glass layer includes: performing the second laser treatment on the silicate glass layer located in the second laser region to form the sparse portion located in the second laser region; 5. The method for manufacturing a solar cell according to claim 3 or 4.

6. an orthogonal projection area of ​​the first laser region onto the substrate is different from an orthogonal projection area of ​​the second laser region onto the substrate, and / or an orthogonal projection area of ​​the first laser region onto the substrate at least partially overlaps or does not overlap with an orthogonal projection area of ​​the second laser region onto the substrate; The method for manufacturing a solar cell according to claim 5 .

7. The step of performing the second etching process on at least the second surface includes: etching the first surface using a second sequence hydrofluoric acid process to remove the silicate glass layer located on the first surface; etching the first surface and the second surface using a second texturing process to remove the doped polysilicon layer, the first diffusion barrier layer, and the second diffusion barrier layer located on the first surface to expose the first textured surface and the doped portion, and removing the sparse portion and the doped polysilicon layer located in the second laser region to form the second textured surface; The method for manufacturing a solar cell according to claim 5 .

8. After the second texturing process, cleaning the second surface using an acid cleaning process to remove the silicate glass layer located in the second non-laser area and expose the doped polysilicon layer located in the second non-laser area; The method for manufacturing a solar cell according to claim 7 .

9. The step of performing the first etching process on the first surface includes: etching the first surface using a first texturing process to remove the activated portion and form the first textured surface; The method for manufacturing a solar cell according to claim 1 .

10. In the step of performing the first laser treatment, an oxide layer is formed on the doped layer; the step of performing the first etching process on the first surface further comprises etching the first surface using a first chain hydrofluoric acid process to remove the oxide layer before etching the first surface using the first texturing process. The method for manufacturing a solar cell according to claim 9 .

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