Solar cell and photovoltaic module

Abstract

The utility model relates to the technical field of solar cells, in particular to a solar cell and a photovoltaic module. The solar cell comprises a silicon substrate, a first dielectric layer, a doped silicon carbide layer, a patterned first doped polycrystalline silicon layer and a first electrode. The first dielectric layer covers the light receiving surface of the silicon substrate. And the doped silicon carbide layer covers one surface, deviating from the silicon substrate, of the first dielectric layer. And the first doped polycrystalline silicon layer is arranged on one surface, deviating from the silicon substrate, of the doped silicon carbide layer. The first electrode is arranged on one surface, deviating from the silicon substrate, of the first doped polycrystalline silicon layer, the first electrode is in ohmic contact with the first doped polycrystalline silicon layer, and a graphical region of the first doped polycrystalline silicon layer corresponds to a setting region of the first electrode. The light-receiving surface of the solar cell has lower recombination degree and less optical parasitic absorption, and also has better passivation effect and lower transverse resistance, so that the performance of the solar cell is improved.

Description

Technical Field

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

[0002] The current passivated contact cell includes a silicon substrate, and a doped polysilicon layer is provided on the light-receiving surface of the silicon substrate. The doped polysilicon layer is in ohmic contact with the metal electrode to avoid direct contact between the metal electrode and the silicon substrate and reduce metal contact recombination. However, the optical parasitic absorption of the doped polysilicon layer is serious. Although the optical parasitic absorption can be reduced by reducing the coverage area of ​​the doped polysilicon layer, the reduction in the coverage area of ​​the doped polysilicon layer on the light-receiving surface causes poor passivation effect on the light-receiving surface and increased lateral resistance, making it difficult to improve the performance of the solar cell. Utility Model Content

[0003] The embodiment of the present application discloses a solar cell, the light-receiving surface of which has less metal contact recombination and less optical parasitic absorption, and also has better passivation effect and lower lateral resistance, so that the performance of the solar cell is improved.

[0004] In order to achieve the above objectives, in a first aspect, the present application discloses a solar cell, comprising:

[0005] Silicon substrate;

[0006] A first dielectric layer, wherein the first dielectric layer covers the light-receiving surface of the silicon substrate;

[0007] a doped silicon carbide layer, wherein the doped silicon carbide layer covers a side of the first dielectric layer facing away from the silicon substrate;

[0008] a patterned first doped polysilicon layer, wherein the first doped polysilicon layer is disposed on a side of the doped silicon carbide layer away from the silicon substrate, and the first doped polysilicon layer and the doped silicon carbide layer have the same conductivity type; and

[0009] A first electrode is disposed on a surface of the first doped polysilicon layer facing away from the silicon substrate, the first electrode is in ohmic contact with the first doped polysilicon layer, and a patterned area of ​​the first doped polysilicon layer corresponds to an area where the first electrode is disposed.

[0010] In a possible implementation of the first aspect, the first doped polysilicon layer includes a first doped polysilicon sublayer and a second doped polysilicon sublayer stacked in sequence away from the silicon substrate, the surface concentration of the second doped polysilicon sublayer is greater than the surface concentration of the first doped polysilicon sublayer, and the first electrode is in ohmic contact with the second doped polysilicon sublayer.

[0011] In a possible implementation of the first aspect, the first doped polysilicon layer is a first P-type doped polysilicon layer, and the surface concentration of the first doped polysilicon sublayer is 5×10 19 atoms / cm 3 ~1×10 20 atoms / cm 3 The thickness of the first doped polysilicon sublayer is 20 nm to 100 nm, and the surface concentration of the second doped polysilicon sublayer is 2×10 20 atoms / cm 3 ~5×10 20 atoms / cm 3 , the thickness of the second doped polysilicon sublayer is 20nm to 100nm;

[0012] Or, the first doped polysilicon layer is a first N-type doped polysilicon layer, and the surface concentration of the first doped polysilicon sublayer is 3×10 20 atoms / cm 3 ~8×10 20 atoms / cm 3 The thickness of the first doped polysilicon sublayer is 20 nm to 50 nm, and the surface concentration of the second doped polysilicon sublayer is 9×10 20 atoms / cm 3 ~5×10 21 atoms / cm 3 , the thickness of the second doped polysilicon sublayer is 40nm to 70nm.

[0013] In a possible implementation of the first aspect, the solar cell further includes:

[0014] a second dielectric layer, wherein the second dielectric layer covers the backlight surface of the silicon substrate;

[0015] a second doped polysilicon layer, the second doped polysilicon layer covering a side of the second dielectric layer away from the silicon substrate; the conductivity type of the second doped polysilicon layer is opposite to the conductivity type of the first doped polysilicon layer; and

[0016] A second electrode is disposed on a surface of the second doped polysilicon layer facing away from the silicon substrate, and the second electrode is in ohmic contact with the second doped polysilicon layer.

[0017] In a possible implementation of the first aspect, the second doped polysilicon layer includes a third doped polysilicon sublayer and a patterned fourth doped polysilicon sublayer, the third doped polysilicon sublayer covers a side of the second dielectric layer away from the silicon substrate, the fourth doped polysilicon sublayer is arranged on a side of the third doped polysilicon sublayer away from the silicon substrate, the surface concentration of the fourth doped polysilicon sublayer is greater than the surface concentration of the third doped polysilicon sublayer, the patterned area of ​​the fourth doped polysilicon sublayer corresponds to the setting area of ​​the second electrode, and the second electrode is in ohmic contact with the fourth doped polysilicon sublayer.

[0018] In a possible implementation of the first aspect, the second doped polysilicon layer is a second N-type doped polysilicon layer, and the surface concentration of the third doped polysilicon sublayer is 2×10 20 atoms / cm 3 ~8×10 20 atoms / cm 3 The thinnest thickness of the third doped polysilicon sublayer is 50nm to 150nm, and the surface concentration of the fourth doped polysilicon sublayer is 8×10 20 atoms / cm 3 ~5×10 21 atoms / cm 3 , the thickness of the fourth doped polysilicon sublayer is 50nm to 100nm;

[0019] Or, the second doped polysilicon layer is a second P-type doped polysilicon layer, and the surface concentration of the third doped polysilicon sublayer is 5×10 18 atoms / cm 3 ~1×10 20 atoms / cm 3 The thinnest thickness of the third doped polysilicon sublayer is 60nm to 250nm, and the surface concentration of the fourth doped polysilicon sublayer is 1×10 20 atoms / cm 3 ~6×10 20 atoms / cm 3 , the thickness of the fourth doped polysilicon sublayer is 30nm to 150nm.

[0020] In a possible implementation of the first aspect, the solar cell further includes:

[0021] a first anti-reflection layer, a portion of the first anti-reflection layer is disposed on a surface of the first doped polysilicon layer facing away from the silicon substrate, the first electrode penetrates the first anti-reflection layer and is in ohmic contact with the first doped polysilicon layer, and a portion of the first anti-reflection layer is disposed on a surface of the doped silicon carbide layer facing away from the silicon substrate; and

[0022] A second anti-reflection layer is provided on a surface of the second doped polysilicon layer facing away from the silicon substrate, and the second electrode penetrates through the second anti-reflection layer and is in ohmic contact with the second doped polysilicon layer.

[0023] In a possible implementation manner of the first aspect, the silicon substrate is an N-type silicon substrate, and the resistivity of the silicon substrate is 0.3Ω·cm to 7Ω·cm;

[0024] And / or, the first dielectric layer is a silicon oxide layer;

[0025] And / or, the thickness of the first dielectric layer is 0.1 nm to 5 nm;

[0026] And / or, the second dielectric layer is a silicon oxide layer;

[0027] And / or, the thickness of the second dielectric layer is 0.1 nm to 5 nm;

[0028] And / or, the first electrode is a silver electrode, an aluminum electrode or a nickel-copper electrode;

[0029] And / or, the second electrode is a silver electrode, an aluminum electrode or a nickel-copper electrode;

[0030] and / or, the first anti-reflection layer comprises at least one of a silicon nitride layer, a silicon oxynitride layer or a silicon oxide layer;

[0031] And / or, the thickness of the first anti-reflection layer is 60nm to 130nm;

[0032] and / or, the second anti-reflection layer comprises at least one of a silicon nitride layer, a silicon oxynitride layer or a silicon oxide layer;

[0033] And / or, the second anti-reflection layer has a thickness of 60 nm to 130 nm.

[0034] In a possible implementation of the first aspect, the portion of the doped silicon carbide layer corresponding to the patterned area of ​​the first doped polysilicon layer is a first doped silicon carbide sublayer and the rest of the doped silicon carbide layer is a second doped silicon carbide sublayer, and the doping concentration of the first doped silicon carbide sublayer is greater than the doping concentration of the second doped silicon carbide sublayer.

[0035] In a possible implementation of the first aspect, the doped silicon carbide layer is a P-type doped silicon carbide layer, and the doping concentration of the first doped silicon carbide sublayer is 5×10 19 atoms / cm 3 ~1×10 20 atoms / cm 3 , the doping concentration of the second doped silicon carbide sublayer is 1×10 18atoms / cm 3 ~5×10 19 atoms / cm 3 , the thickness of the doped silicon carbide layer is 5nm to 50nm;

[0036] Or, the doped silicon carbide layer is an N-type doped silicon carbide layer, and the doping concentration of the first doped silicon carbide sublayer is 3×10 20 atoms / cm 3 ~1×10 21 atoms / cm 3 , the doping concentration of the second doped silicon carbide sublayer is 1×10 20 atoms / cm 3 ~7×10 20 atoms / cm 3 The thickness of the doped silicon carbide layer is 5 nm to 50 nm, wherein the doping type of the doped silicon carbide layer is the same as the doping type of the silicon substrate.

[0037] In a second aspect, an embodiment of the present application discloses a photovoltaic module, comprising the solar cell as described in the first aspect.

[0038] Compared with the prior art, the beneficial effect of the present application is that the solar cell avoids direct contact between the first electrode and the silicon substrate by making an ohmic contact with the first doped polysilicon layer through the first electrode, thereby reducing metal contact recombination. Since the first doped polysilicon layer is located on the light-receiving surface, in order to avoid severe optical parasitic absorption, the first doped polysilicon layer is patterned, and the patterned area of ​​the first doped polysilicon layer corresponds to the setting area of ​​the first electrode, and by reducing the light-shielding area of ​​the first doped polysilicon layer on the light-receiving surface, the first doped polysilicon layer can be used to form a good contact with the first electrode without causing severe optical parasitic absorption.

[0039] However, the light-receiving surface outside the patterned area will lack the field passivation effect and carrier transport effect of the first doped polysilicon layer. In order to passivate the light-receiving surface outside the above-mentioned patterned area, the first dielectric layer of the solar cell covers the light-receiving surface, and the doped silicon carbide layer covers the side of the first dielectric layer away from the silicon substrate, which is equivalent to the doped silicon carbide layer also covering the light-receiving surface. The first dielectric layer and the doped silicon carbide layer are combined to passivate the light-receiving surface outside the above-mentioned patterned area, which has a good passivation effect. Furthermore, carrier transport on the light-receiving surface can be transmitted to the first electrode through the doped silicon carbide layer to reduce the lateral resistance.

[0040] Compared with the first doped polysilicon layer, the optical bandgap of the doped silicon carbide layer is wider. Covering the light-receiving surface with the doped silicon carbide layer can provide a field passivation effect on the entire light-receiving surface while avoiding serious optical parasitic absorption. Compared with the doped silicon carbide layer, the first doped polysilicon layer can more easily achieve high-concentration doping, and the high-concentration doped first doped polysilicon layer has a better contact effect with the first electrode.

[0041] The light-receiving surface of the solar cell has good contact effect, less metal contact recombination and less optical parasitic absorption, and also has good passivation effect and lower lateral resistance, so that the performance of the solar cell is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 A schematic diagram of the structure of a solar cell provided in an embodiment of the present application.

[0044] Description of reference numerals:

[0045] 100, solar cell; 110, silicon substrate; 111, light-receiving surface; 112, backlight surface; 120, first dielectric layer; 130, doped silicon carbide layer; 131, first doped silicon carbide sublayer; 132, second doped silicon carbide sublayer; 140, first doped polysilicon layer; 141, first doped polysilicon sublayer; 142, second doped polysilicon sublayer; 150a, first electrode; 150b, second electrode; 160, second dielectric layer; 170, second doped polysilicon layer; 171, third doped polysilicon sublayer; 172, fourth doped polysilicon sublayer; 180, first anti-reflection layer; 190, second anti-reflection layer. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0047] In this application, the terms "upper", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0048] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0049] In addition, the term "disposed" should be understood in a broad sense. For example, it can be directly connected, or indirectly connected through an intermediate medium, or it can be internally connected between two devices, elements or components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0050] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0051] In the related art, the passivated contact solar cell is provided with a passivated contact structure on the backlight side of the silicon substrate, and the light-receiving side of the silicon substrate forms an emitter through a diffusion process. Taking the N-type solar cell as an example, the light-receiving side of the silicon substrate is formed into an emitter through a boron diffusion process. In order to ensure good contact between the metal electrode and the light-receiving side, the overall doping concentration of the light-receiving side is relatively high, but this also leads to serious Auger recombination problems.

[0052] Solar cells in related technologies can alleviate the serious problem of Auger recombination on the light-receiving surface through selective emitter technology, forming a high-doping concentration deep junction in the metal electrode setting area of ​​the light-receiving surface to improve contact performance. The light-receiving surface area outside the metal electrode setting area is set as a low-doping concentration shallow junction, but the metal electrode is still in direct contact with the silicon substrate, and the metal contact recombination is still relatively serious, which has become the main factor limiting the efficiency improvement of selective emitter solar cells.

[0053] Furthermore, the solar cell in the related art contacts the metal electrode through the doped polysilicon layer to avoid direct contact between the metal electrode and the silicon substrate, and reduces the coverage area of ​​the doped polysilicon layer by setting the doped polysilicon layer as a patterned film layer, thereby reducing the optical parasitic absorption caused by the doped polysilicon layer. Since the doped polysilicon layer plays both a field passivation role and a carrier transmission role, the area of ​​the light-receiving surface of the silicon substrate where the doped polysilicon layer is not set lacks a field passivation effect and cannot transmit carriers. In other words, the reduced coverage area of ​​the doped polysilicon layer on the light-receiving surface leads to poor passivation effect on the light-receiving surface and increased lateral resistance, which makes it difficult to improve the performance of the solar cell.

[0054] Based on the above analysis, the present application provides a solar cell, which avoids direct contact between the first electrode and the silicon substrate by making ohmic contact between the first electrode and the patterned first doped polysilicon layer, and the patterned area of ​​the first doped polysilicon layer corresponds to the setting area of ​​the first electrode, and the light-receiving surface has lower metal contact recombination and less optical parasitic absorption. Furthermore, a first dielectric layer and a doped silicon carbide layer are used in combination to passivate the light-receiving surface in the area outside the above-mentioned patterned area. Carrier transmission on the light-receiving surface can be transmitted to the first electrode through the doped silicon carbide layer to reduce the lateral resistance. The light-receiving surface of the solar cell has lower metal contact recombination and less optical parasitic absorption, and can also have a good passivation effect and a lower lateral resistance, so that the performance of the solar cell is improved.

[0055] See also Figure 1 The embodiment of the present application discloses a solar cell 100, including a silicon substrate 110, a first dielectric layer 120, a doped silicon carbide layer 130, a patterned first doped polysilicon layer 140 and a first electrode 150a.

[0056] The first dielectric layer 120 covers the light receiving surface 111 of the silicon substrate 110 . The term “covering” means that the first dielectric layer 120 covers or hides the entire light receiving surface 111 .

[0057] The doped silicon carbide layer 130 covers the side of the first dielectric layer 120 facing away from the silicon substrate 110 . The term “covering” means that the doped silicon carbide layer 130 covers and hides the entire surface of the first dielectric layer 120 facing away from the silicon substrate 110 .

[0058] The first doped polysilicon layer 140 is disposed on the side of the doped silicon carbide layer 130 away from the silicon substrate 110. Since the first doped polysilicon layer 140 is a patterned film layer, the first doped polysilicon layer 140 only covers and hides a local area on the side of the first doped polysilicon layer 140 away from the silicon substrate 110. And the first doped polysilicon layer 140 and the doped silicon carbide layer 130 have the same conductivity type, and it can be understood that the first doped polysilicon layer 140 and the doped silicon carbide layer 130 are both N-type doped or both P-type doped.

[0059] The first electrode 150a is disposed on a surface of the first doped polysilicon layer 140 facing away from the silicon substrate 110. Optionally, the first electrode 150a is a silver electrode, an aluminum electrode or a nickel-copper electrode. The first electrode 150a is in ohmic contact with the first doped polysilicon layer 140, and the patterned area of ​​the first doped polysilicon layer 140 corresponds to the area where the first electrode 150a is disposed. The term "corresponding" may mean that the first doped polysilicon layer 140 and the first electrode 150a just correspond, for example, the line widths of the first doped polysilicon layer 140 and the first electrode 150a are the same, or the line width of the first doped polysilicon layer 140 is slightly wider than that of the first electrode 150a, so as to reduce the stringent requirements for alignment accuracy when printing the first electrode 150a, and ensure that the process window is wide while meeting the ohmic contact requirements of the two.

[0060] The solar cell 100 makes ohmic contact with the first doped polysilicon layer 140 through the first electrode 150a to avoid direct contact between the first electrode 150a and the silicon substrate 110, thereby reducing metal contact recombination. Since the first doped polysilicon layer 140 is located on the light-receiving surface 111, in order to avoid severe optical parasitic absorption, the first doped polysilicon layer 140 is patterned, and the patterned area of ​​the first doped polysilicon layer 140 corresponds to the area where the first electrode 150a is set. By reducing the light-shielding area of ​​the first doped polysilicon layer 140 on the light-receiving surface 111, the first doped polysilicon layer 140 can be used to form a good contact with the first electrode 150a without causing severe optical parasitic absorption.

[0061] However, the light-receiving surface 111 outside the patterned area will lack the field passivation effect and carrier transport effect of the first doped polysilicon layer 140. In order to passivate the light-receiving surface 111 outside the above-mentioned patterned area, the first dielectric layer 120 of the solar cell 100 covers the light-receiving surface 111, and the doped silicon carbide layer 130 covers the side of the first dielectric layer 120 away from the silicon substrate 110, which is equivalent to the doped silicon carbide layer 130 also covering the light-receiving surface 111. The first dielectric layer 120 and the doped silicon carbide layer 130 are combined to passivate the light-receiving surface 111 outside the above-mentioned patterned area, which has a good passivation effect. Further, the carrier transport on the light-receiving surface 111 can be transmitted to the first electrode through the doped silicon carbide layer 130 to reduce the lateral resistance.

[0062] Compared with the first doped polysilicon layer 140, the optical bandgap of the doped silicon carbide layer 130 is wider, and the use of the doped silicon carbide layer 130 to cover the light-receiving surface 111 can provide a field passivation effect on the entire light-receiving surface 111, while avoiding severe optical parasitic absorption. Compared with the doped silicon carbide layer 130, the first doped polysilicon layer 140 can more easily achieve high-concentration doping, and the high-concentration doped first doped polysilicon layer 140 has a better contact effect with the first electrode 150a.

[0063] In summary, the light-receiving surface 111 of the solar cell 100 has good contact effect, less metal contact recombination and less optical parasitic absorption, and also has good passivation effect and lower lateral resistance, so that the performance of the solar cell 100 is improved.

[0064] In a possible implementation of the first aspect, the silicon substrate 110 is an N-type silicon substrate, and the resistivity of the silicon substrate 110 is 0.3Ω·cm to 7Ω·cm, including any point value within the resistivity range, for example, 0.3Ω·cm, 3.5Ω·cm or 7Ω·cm.

[0065] The material of the first dielectric layer 120 may be a dielectric material, such as any one of silicon oxide, magnesium fluoride, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide or titanium oxide. Preferably, the first dielectric layer 120 is a silicon oxide layer. This is because the silicon oxide layer has excellent passivation properties, can minimize the recombination loss of photogenerated carriers on the surface of the silicon substrate 110, and is a film with excellent durability to subsequent high-temperature processes.

[0066] The first dielectric layer 120 acts as a barrier for electrons and holes, and can be combined with the first doped polysilicon layer 140 to allow carriers to selectively pass through. The first dielectric layer 120 can also have a pinhole channel effect, allowing carriers in the solar cell 100 to move freely, and selectively passing through the first doped polysilicon layer 140 is generated, which is conducive to reducing carrier recombination losses. In addition, the first dielectric layer 120 can be used as a diffusion barrier to prevent the dopant of the first doped polysilicon layer 140 from diffusing into the silicon substrate 110.

[0067] In order to better provide interface passivation for the silicon substrate 110 , the thickness of the first dielectric layer 120 is 0.1 nm to 5 nm, including any value within the thickness range, such as 1.4 nm or 2.5 nm.

[0068] In a possible implementation of the first aspect, the first doped polysilicon layer 140 includes a first doped polysilicon sublayer 141 and a second doped polysilicon sublayer 142 stacked in sequence away from the silicon substrate 110, the surface concentration of the second doped polysilicon sublayer 142 is greater than the surface concentration of the first doped polysilicon sublayer 141, and the first electrode 150a is in ohmic contact with the second doped polysilicon sublayer 142.

[0069] In the related art, the doped polysilicon layer is a film layer with a consistent doping concentration everywhere. This is because the doped polysilicon layer is formed by annealing the doped amorphous silicon layer, and the annealing process makes the doping concentration of the doped polysilicon layer consistent everywhere. During the annealing process, the doping elements in the doped amorphous silicon layer will diffuse into the silicon substrate 110. The higher the doping concentration of the doped amorphous silicon layer, the more doping elements diffuse into the silicon substrate 110, the higher the surface concentration of the light-receiving surface 111 of the silicon substrate 110, and the more serious the Auger recombination. Therefore, in order to alleviate the Auger recombination, the doping concentration of the doped amorphous silicon layer is preferably a lower doping concentration, thereby reducing the doping elements diffused into the silicon substrate 110 during annealing. However, the lower the doping concentration of the doped amorphous silicon layer, the lower the surface concentration of the doped polysilicon layer obtained after annealing, and the higher the contact resistivity between the doped polysilicon layer and the metal electrode. In other words, although the method of using a doped amorphous silicon layer with a low doping concentration to make a doped polysilicon layer reduces Auger recombination, the contact resistivity between the doped polysilicon layer and the metal electrode increases.

[0070] The first doped polysilicon layer 140 of the present application is a surface concentration gradient structure. Among them, the first doped polysilicon sublayer 141 closer to the silicon substrate 110 has a lower surface concentration. The lower surface concentration means that when the first doped polysilicon sublayer 141 is made, less doping elements diffuse into the silicon substrate 110 through the first dielectric layer 120, thereby avoiding the first dielectric layer 120 from being damaged and reducing the Auger recombination of the light-receiving surface 111. The second doped polysilicon sublayer 142 that is in ohmic contact with the first electrode 150a has a higher surface concentration, and the contact resistivity between the first electrode 150a and the second doped polysilicon sublayer 142 is low, so that the solar cell 100 takes into account both low contact resistivity and less Auger recombination.

[0071] In a possible implementation of the first aspect, the first doped polysilicon layer 140 is a first P-type doped polysilicon layer. In order to ensure that the first doped polysilicon sublayer 141 has a low resistivity and a good field passivation effect, the surface concentration of the first doped polysilicon sublayer 141 should not be less than 5×10 19 atoms / cm 3 In order to reduce the doping elements diffused into the silicon substrate 110 and reduce the Auger recombination of the light receiving surface 111, the surface concentration of the first doped polysilicon sublayer 141 should not be higher than 1×10 20 atoms / cm3 Preferably, the surface concentration of the first doped polysilicon sublayer 141 is 5×10 19 atoms / cm 3 ~1×10 20 atoms / cm 3 Including any point value within the surface concentration range, for example, 5×10 19 atoms / cm 3 , 8×10 19 atoms / cm 3 or 1×10 20 atoms.

[0072] In order to avoid the first doped polysilicon sublayer 141 being too thin, which results in the total thickness of the first doped polysilicon layer 140 being too low and being easily burned through when the first electrode 150a is made, the thickness of the first doped polysilicon sublayer 141 should not be less than 20nm. In order to avoid serious optical parasitic absorption due to the thickness of the first doped polysilicon sublayer 141 being too high, the thickness of the first doped polysilicon sublayer 141 should not be greater than 100nm. Preferably, the thickness of the first doped polysilicon sublayer 141 is 20nm to 100nm, including any point value within the thickness range, for example, 20nm, 60nm or 100nm.

[0073] In order to make the second doped polysilicon sublayer 142 and the first electrode 150a have a lower contact resistivity, the surface concentration of the second doped polysilicon sublayer 142 should not be less than 2×10 20 atoms / cm 3 Since it is difficult to achieve high doping concentration with P-type doping, in order to reduce the difficulty of manufacturing, the second doped polysilicon sublayer 142 should not be higher than 5×10 20 atoms / cm 3 Preferably, the surface concentration of the second doped polysilicon sublayer 142 is 2×10 20 atoms / cm 3 ~5×10 20 atoms / cm 3 Including any point value within the surface concentration range, for example, 2×10 20 atoms / cm 3 , 3×10 20 atoms / cm 3 or 5×10 20 atoms / cm 3 .

[0074] In order to avoid the second doped polysilicon sublayer 142 being too thin, which results in the total thickness of the first doped polysilicon layer 140 being too low and being easily burned through when the second electrode 150b is made, the thickness of the second doped polysilicon sublayer 142 should not be less than 20nm. In order to avoid serious optical parasitic absorption due to the thickness of the second doped polysilicon sublayer 142 being too high, the thickness of the second doped polysilicon sublayer 142 should not be greater than 100nm. Preferably, the thickness of the second doped polysilicon sublayer 142 is 20nm to 100nm, including any point value within the thickness range, for example, 20nm, 60nm or 100nm.

[0075] In a possible implementation of the first aspect, the first doped polysilicon layer 140 is a first N-type doped polysilicon layer. In order to ensure that the first doped polysilicon sublayer 141 itself has a low resistivity, the surface concentration of the first doped polysilicon sublayer 141 should not be less than 3×10 20 atoms / cm 3 In order to reduce the doping elements diffused into the silicon substrate 110 to reduce Auger recombination, the surface concentration of the first doped polysilicon sublayer 141 should not be higher than 8×10 20 atoms / cm 3 Preferably, the surface concentration of the first doped polysilicon sublayer 141 is 3×10 20 atoms / cm 3 ~8×10 20 atoms / cm 3 Including any point value within the surface concentration range, for example, 3×10 20 atoms / cm 3 , 5×10 20 atoms / cm 3 or 8×10 20 atoms / cm 3 .

[0076] In order to avoid the first doped polysilicon sublayer 141 being too thin, which results in the total thickness of the first doped polysilicon layer 140 being too low and being easily burned through when the first electrode 150a is made, the thickness of the first doped polysilicon sublayer 141 should not be less than 20nm. In order to avoid serious optical parasitic absorption due to the thickness of the first doped polysilicon sublayer 141 being too high, the thickness of the first doped polysilicon sublayer 141 should not be greater than 50nm. Preferably, the thickness of the first doped polysilicon sublayer 141 is 20nm to 50nm, including any point value within the thickness range, for example, 20nm, 35nm or 50nm.

[0077] In order to make the second doped polysilicon sublayer 142 and the first electrode 150a have a lower contact resistivity, the surface concentration of the second doped polysilicon sublayer 142 should not be less than 9×10 20 atoms / cm3 In order to reduce the difficulty of manufacturing, the surface concentration of the second doped polysilicon sublayer 142 should not be higher than 5×10 21 atoms / cm 3 Preferably, the surface concentration of the second doped polysilicon sublayer 142 is 9×10 20 atoms / cm 3 ~5×10 21 atoms / cm 3 Including any point value within the surface concentration range, for example, 9×10 20 atoms / cm 3 , 2×10 21 atoms / cm 3 or 5×10 21 atoms / cm 3 .

[0078] If the second doped polysilicon sublayer 142 is less than 40 nm, it is easy to burn through the second doped polysilicon sublayer 142 when making the first electrode 150a. In order to avoid serious optical parasitic absorption of incident light by the region between the first electrode 150a and the first doped polysilicon layer 140, the thickness of the second doped polysilicon sublayer 142 should not be greater than 70 nm. Preferably, the thickness of the second doped polysilicon sublayer 142 is 40 nm to 70 nm, including any value within the thickness range, such as 40 nm, 55 nm or 70 nm.

[0079] In a possible implementation of the first aspect, the solar cell 100 further includes a second dielectric layer 160 , a second doped polysilicon layer 170 , and a second electrode 150 b .

[0080] The second dielectric layer 160 covers the backlight surface 112 of the silicon substrate 110 .

[0081] The second doped polysilicon layer 170 covers the side of the second dielectric layer 160 away from the silicon substrate 110. The conductivity type of the second doped polysilicon layer 170 is opposite to the conductivity type of the first doped polysilicon layer 140. A PN junction is formed between the second doped polysilicon layer 170 and the silicon substrate 110 or between the first doped polysilicon layer 140 and the silicon substrate 110. In other words, the PN junction is located at the light-receiving surface 111 or the backlight surface 112.

[0082] The second electrode 150b is disposed on a surface of the second doped polysilicon layer 170 facing away from the silicon substrate 110, and the second electrode 150b is in ohmic contact with the second doped polysilicon layer 170. Optionally, the second electrode 150b is a silver electrode, an aluminum electrode or a nickel-copper electrode.

[0083] The solar cell 100 has a double-sided passivation contact structure, that is, the light-receiving surface 111 is formed of a passivation contact structure of the light-receiving surface 111 through the first dielectric layer 120, the doped silicon carbide layer 130 and the patterned first doped polysilicon layer 140, and the backlight surface 112 is formed of a passivation contact structure of the backlight surface 112 through the second dielectric layer 160 and the second doped polysilicon layer 170. Compared with the solar cell in the related art that only sets the passivation contact structure on the light-receiving surface or the backlight surface, the solar cell 100 of the present application has good passivation effect on both the light-receiving surface 111 and the backlight surface 112, and lower metal contact recombination.

[0084] In a possible implementation of the first aspect, the material of the second dielectric layer 160 may be a dielectric material, such as any one of silicon oxide, magnesium fluoride, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide, or titanium oxide. Preferably, the second dielectric layer 160 is a silicon oxide layer. This is because the silicon oxide layer has excellent passivation properties, can minimize the recombination loss of photogenerated carriers on the surface of the silicon substrate 110, and is a film with excellent durability to subsequent high-temperature processes.

[0085] The second dielectric layer 160, as a barrier for electrons and holes, can be combined with the second doped polysilicon layer 170 to allow carriers to selectively pass through. The second dielectric layer 160 can also have a pinhole channel effect, allowing carriers in the solar cell 100 to move freely, and selectively passing through the second doped polysilicon layer 170 to generate carriers is conducive to reducing carrier recombination losses. In addition, the second dielectric layer 160 can be used as a diffusion barrier to prevent the dopant of the second doped polysilicon layer 170 from diffusing into the silicon substrate 110.

[0086] In order to better provide interface passivation for the silicon substrate 110 , the thickness of the second dielectric layer 160 is 0.1 nm to 5 nm, including any value within the thickness range, such as 0.1 nm, 3 nm or 5 nm.

[0087] In a possible implementation of the first aspect, the second doped polysilicon layer 170 includes a third doped polysilicon sublayer 171 and a patterned fourth doped polysilicon sublayer 172, the third doped polysilicon sublayer 171 covers a side of the second dielectric layer 160 away from the silicon substrate 110, and the fourth doped polysilicon sublayer 172 is disposed on a side of the third doped polysilicon sublayer 171 away from the silicon substrate 110. The surface concentration of the fourth doped polysilicon sublayer 172 is greater than the surface concentration of the third doped polysilicon sublayer 171, the patterned region of the fourth doped polysilicon sublayer 172 corresponds to the region where the second electrode 150b is disposed, and the second electrode 150b is in ohmic contact with the fourth doped polysilicon sublayer 172. The term "corresponding" can mean that the setting areas of the fourth doped polysilicon sublayer 172 and the second electrode 150b just correspond, for example, the line widths of the fourth doped polysilicon sublayer 172 and the second electrode 150b are the same, or the line width of the fourth doped polysilicon sublayer 172 is slightly wider than the second electrode 150b, so as to reduce the stringent requirements for alignment accuracy when printing the second electrode 150b, ensuring a wider process window while meeting the ohmic contact requirements between the two.

[0088] As described above, the doped polysilicon layer in the related art is a film layer with a uniform doping concentration everywhere, and it is difficult to take into account both low contact resistivity and less Auger recombination. The second doped polysilicon layer 170 of the present application is a surface concentration gradient variation structure, wherein the third doped polysilicon sublayer 171 closer to the silicon substrate 110 has a lower surface concentration, and the lower surface concentration means that when the third doped polysilicon sublayer 171 is made, fewer doping elements diffuse into the silicon substrate 110 through the first dielectric layer 120, thereby avoiding the second dielectric layer 160 from being damaged and reducing the Auger recombination of the backlight surface 112. The fourth doped polysilicon sublayer 172 that makes ohmic contact with the second electrode 150b has a higher surface concentration, and the contact resistivity between the second electrode 150b and the fourth doped polysilicon sublayer 172 is low, so that the solar cell 100 takes into account both low contact resistivity and less Auger recombination.

[0089] In a possible implementation of the first aspect, the second doped polysilicon layer 170 is a second N-type doped polysilicon layer. In order to ensure that the third doped polysilicon sublayer 171 itself has a lower resistivity and a better field passivation effect, the surface concentration of the third doped polysilicon sublayer 171 should not be less than 2×10 20 atoms / cm 3 In order to reduce the doping elements diffused into the silicon substrate 110 to reduce Auger recombination, the surface concentration of the third doped polysilicon sublayer 171 should not be higher than 8×10 20 atoms / cm 3 Preferably, the surface concentration of the third doped polysilicon sublayer 171 is 2×10 20 atoms / cm3 ~8×10 20 atoms / cm 3 .

[0090] In order to avoid the third doped polysilicon sublayer 171 being too thin, which results in the second doped polysilicon layer 170 being too thin and easily burned through during the production of the second electrode 150b, the thickness of the third doped polysilicon sublayer 171 should not be less than 50nm. In order to avoid serious optical parasitic absorption due to the third doped polysilicon sublayer 171 being too thick, the thickness of the third doped polysilicon sublayer 171 should not be greater than 150nm. Preferably, the thickness of the third doped polysilicon sublayer 171 is 50nm to 150nm, including any point value within the thickness range, such as 50nm, 100nm or 150nm.

[0091] In order to make the fourth doped polysilicon sublayer 172 and the second electrode 150b have a lower contact resistivity, the surface concentration of the fourth doped polysilicon sublayer 172 should not be less than 8×10 20 atoms / cm 3 In order to reduce the difficulty of manufacturing, the surface concentration of the fourth doped polysilicon sublayer 172 should not be higher than 5×10 21 atoms / cm 3 Preferably, the surface concentration of the fourth doped polysilicon sublayer 172 is 8×10 20 atoms / cm 3 ~5×10 21 atoms / cm 3 .

[0092] If the fourth doped polysilicon sublayer 172 is less than 50 nm, it is easy to burn through the fourth doped polysilicon sublayer 172 when making the second electrode 150b. If the thickness of the fourth doped polysilicon sublayer 172 is greater than 100 nm, it will cause more serious optical parasitic absorption. Preferably, the thickness of the fourth doped polysilicon sublayer 172 is 50 nm to 100 nm, including any point value within the thickness range, for example, 50 nm, 70 nm or 100 nm.

[0093] In a possible implementation of the first aspect, the second doped polysilicon layer 170 is a second P-type doped polysilicon layer. In order to ensure that the third doped polysilicon sublayer 171 itself has a low resistivity, the surface concentration of the third doped polysilicon sublayer 171 should not be less than 5×10 18 atoms / cm 3 In order to reduce the doping elements diffused into the silicon substrate 110, the surface concentration of the third doped polysilicon sublayer 171 should not be higher than 1×10 20 atoms / cm 3 Preferably, the surface concentration of the third doped polysilicon sublayer 171 is 5×1018 atoms / cm 3 ~1×10 20 atoms / cm 3 .

[0094] In order to avoid the third doped polysilicon sublayer 171 being too thin, which results in the total thickness of the second doped polysilicon layer 170 being too low and being easily burned through during the production of the second electrode 150b, the thickness of the third doped polysilicon sublayer 171 should not be less than 60nm. In order to avoid the third doped polysilicon sublayer 171 being too thick and causing serious optical parasitic absorption, the thickness of the third doped polysilicon sublayer 171 should not be greater than 250nm. Preferably, the thickness of the third doped polysilicon sublayer 171 is 60nm to 250nm.

[0095] In order to make the fourth doped polysilicon sublayer 172 and the second electrode 150b have a lower contact resistivity, the surface concentration of the fourth doped polysilicon sublayer 172 should not be less than 1×10 20 atoms / cm 3 Due to the characteristics of P-type doping, if the surface concentration of the fourth doped polysilicon sublayer 172 is higher than 6×10 20 atoms / cm 3 Preferably, the surface concentration of the fourth doped polysilicon sublayer 172 is 1×10 20 atoms / cm 3 ~6×10 20 atoms / cm 3 .

[0096] If the fourth doped polysilicon sublayer 172 is less than 30 nm, it is easy to burn through the fourth doped polysilicon sublayer 172 when making the second electrode 150b. If the thickness of the fourth doped polysilicon sublayer 172 is greater than 150 nm, it will cause more serious optical parasitic absorption. Preferably, the thickness of the fourth doped polysilicon sublayer 172 is 30 nm to 150 nm, including any point value within the thickness range, for example, 30 nm, 80 nm or 150 nm.

[0097] In a possible implementation of the first aspect, the portion of the doped silicon carbide layer 130 corresponding to the patterned area of ​​the first doped polysilicon layer 140 is the first doped silicon carbide sublayer 131 and the rest of the doped silicon carbide layer 130 is the second doped silicon carbide sublayer 132, and the doping concentration of the first doped silicon carbide sublayer 131 is greater than the doping concentration of the second doped silicon carbide sublayer 132.

[0098] The doped silicon carbide layer 130 in the related art is a film layer with a uniform doping concentration at all locations, and it is also difficult to simultaneously take into account a low contact resistivity and less Auger recombination. The doped silicon carbide layer 130 of the present application is a surface concentration gradient variation structure, wherein the portion corresponding to the patterned area of ​​the first doped polysilicon layer 140 is a first doped silicon carbide sublayer 131 with a higher doping concentration. The first doped silicon carbide sublayer 131 with a higher doping concentration has a lower resistivity, which is beneficial for carrier transmission to the first electrode 150a. The second doped silicon carbide sublayer 132 has a lower doping concentration to reduce the diffusion of doping elements into the silicon substrate 110 and reduce Auger recombination.

[0099] In a possible implementation of the first aspect, the doped silicon carbide layer 130 is a P-type doped silicon carbide layer. In order to make the first doped silicon carbide sublayer 131 itself have a lower resistivity and a better field passivation effect, the doping concentration of the first doped silicon carbide sublayer 131 should not be less than 5×10 19 atoms / cm 3 Since it is difficult to achieve heavy doping with P-type doping, in order to reduce the difficulty of manufacturing and reduce Auger recombination, the doping concentration of the first doped silicon carbide sublayer 131 should not be higher than 1×10 20 atoms / cm 3 Preferably, the doping concentration of the first doped silicon carbide sublayer 131 is 5×10 19 atoms / cm 3 ~1×10 20 atoms / cm 3 .

[0100] In order to make the second doped silicon carbide sublayer 132 have a lower resistivity, the doping concentration of the second doped silicon carbide sublayer 132 should not be less than 1×10 18 atoms / cm 3 In order to avoid serious Auger recombination on the backlight surface 112, the doping concentration of the second doped silicon carbide sublayer 132 should not be higher than 5×10 19 atoms / cm 3 Preferably, the doping concentration of the second doped silicon carbide sublayer 132 is 1×10 18 atoms / cm 3 ~5×10 19 atoms / cm 3 .

[0101] In order to effectively reduce the lateral resistance, the thickness of the doped silicon carbide layer 130 should not be less than 5 nm. The thicker the doped silicon carbide layer 130 is, the more serious the optical parasitic absorption caused by it is and the longer the deposition time is. The thickness of the doped silicon carbide layer 130 should not be greater than 50 nm. Preferably, the thickness of the doped silicon carbide layer 130 is 5 nm to 50 nm, including any value within the thickness range, such as 5 nm, 30 nm or 50 nm.

[0102] In a possible implementation of the first aspect, the doped silicon carbide layer 130 is an N-type doped silicon carbide layer. In order to make the first doped silicon carbide sublayer 131 itself have a lower resistivity, the doping concentration of the first doped silicon carbide sublayer 131 should not be less than 3×10 20 atoms / cm 3 In order to reduce Auger recombination, the doping concentration of the first doped silicon carbide sublayer 131 should not be higher than 1×10 21 atoms / cm 3 Preferably, the doping concentration of the first doped silicon carbide sublayer 131 is 3×10 20 atoms / cm 3 ~1×10 21 atoms / cm 3 .

[0103] In order to make the second doped silicon carbide sublayer 132 have a lower resistivity and a good field passivation effect, the doping concentration of the second doped silicon carbide sublayer 132 should not be less than 1×10 20 atoms / cm 3 In order to avoid serious Auger recombination on the backlight surface 112, the doping concentration of the second doped silicon carbide sublayer 132 should not be higher than 7×10 20 atoms / cm 3 Preferably, the doping concentration of the second doped silicon carbide sublayer 132 is 1×10 20 atoms / cm 3 ~7×10 20 atoms / cm 3 .

[0104] In order to effectively reduce the lateral resistance, the thickness of the doped silicon carbide layer 130 should not be less than 5nm. The thicker the doped silicon carbide layer 130 is, the more serious the optical parasitic absorption caused by it is and the longer the deposition time is. The thickness of the doped silicon carbide layer 130 should not be greater than 50nm. Preferably, the thickness of the doped silicon carbide layer 130 is 5nm to 50nm, including any point value within the thickness range, for example, 5nm, 30nm or 50nm. The doping type of the doped silicon carbide layer 130 is the same as the doping type of the silicon substrate 110.

[0105] In a possible implementation manner of the first aspect, the solar cell 100 further includes a first anti-reflection layer 180 and a second anti-reflection layer 190 .

[0106] A portion of the first anti-reflection layer 180 is disposed on a surface of the first doped polysilicon layer 140 away from the silicon substrate 110, the first electrode 150a penetrates the first anti-reflection layer 180 and is in ohmic contact with the first doped polysilicon layer 140, and a portion of the first anti-reflection layer 180 is disposed on a surface of the doped silicon carbide layer 130 away from the silicon substrate 110. The function of the first anti-reflection layer 180 is to reduce the reflection of light by the light-receiving surface 111 and increase the absorption of light.

[0107] Optionally, the first anti-reflection layer 180 includes at least one of a silicon nitride layer, a silicon oxynitride layer, or a silicon oxide layer. In other words, the first anti-reflection layer 180 may be one of a silicon nitride layer, a silicon oxynitride layer, or a silicon oxide layer, or a stacked film formed by combining one or more of the three film layers of a silicon nitride layer, a silicon oxynitride layer, or a silicon oxide layer.

[0108] Optionally, if the thickness of the first anti-reflection layer 180 is too thin, the reflectivity cannot be effectively reduced, affecting the light absorption rate and battery efficiency. If the first anti-reflection layer 180 is too thick, the propagation path of the light will be increased, and the diffraction and interference effects of the light will be increased. Preferably, the thickness of the first anti-reflection layer 180 is 60nm to 130nm, including any point value within the thickness range, for example, 60nm, 80nm or 130nm.

[0109] The second anti-reflection layer 190 is disposed on the side of the second doped polysilicon layer 170 facing away from the silicon substrate 110, and the second electrode 150b penetrates the second anti-reflection layer 190 and is in ohmic contact with the second doped polysilicon layer 170. The function of the second anti-reflection layer 190 is to reduce the reflection of light by the backlight surface 112 and increase the absorption of light.

[0110] Optionally, the second anti-reflection layer 190 includes at least one of a silicon nitride layer, a silicon oxynitride layer, or a silicon oxide layer. In other words, the second anti-reflection layer 190 may be one of a silicon nitride layer, a silicon oxynitride layer, or a silicon oxide layer, or a stacked film formed by combining one or more of the three film layers of a silicon nitride layer, a silicon oxynitride layer, or a silicon oxide layer.

[0111] Optionally, if the second anti-reflection layer 190 is too thin, the reflectivity cannot be effectively reduced, affecting the light absorption rate and battery efficiency. If the second anti-reflection layer 190 is too thick, the propagation path of the light will be increased, and the diffraction and interference effects of the light will be increased. The thickness of the second anti-reflection layer 190 is 60nm to 130nm, including any point value within the thickness range, for example, 60nm, 80nm or 130nm.

[0112] The embodiment of the present application further discloses a method for preparing the solar cell 100 as described in the first aspect, comprising the following steps:

[0113] The light-receiving surface 111 and the backlight surface 112 of the silicon substrate 110 are polished.

[0114] On the backlight surface 112 of the silicon substrate 110 , a second dielectric layer 160 , a second doped amorphous silicon layer and a second mask layer are sequentially stacked away from the silicon substrate 110 .

[0115] The second mask layer, the second doped amorphous silicon layer and the coating layer of the second dielectric layer 160 on the light receiving surface 111 and the edge of the silicon substrate 110 are removed.

[0116] The light receiving surface 111 is subjected to a texturing treatment.

[0117] On the light receiving surface 111 of the silicon substrate 110 , a first dielectric layer 120 , an intrinsic silicon carbide layer, a doped amorphous silicon carbide layer and a first doped amorphous silicon layer are sequentially stacked away from the silicon substrate 110 .

[0118] Annealing is performed to crystallize the second doped amorphous silicon layer into a second doped polysilicon layer 170, the first doped amorphous silicon layer into a first doped polysilicon layer 140, and the intrinsic silicon carbide layer and the doped amorphous silicon carbide layer into a doped silicon carbide layer 130; during the annealing process, some doping elements in the first doped polysilicon layer 140, the second doped polysilicon layer 170 and the doped silicon carbide layer 130 are not activated.

[0119] The first doped polysilicon layer 140 and the doped silicon carbide layer 130 are subjected to a first patterning treatment by using an ultraviolet laser. Since the absorption depth of the first doped polysilicon layer 140 to the ultraviolet laser is relatively shallow, a longitudinal temperature gradient is formed by controlling the heating temperature and the pulsed laser energy, and a first doped polysilicon sublayer 141 and a second doped polysilicon sublayer 142 stacked in sequence away from the silicon substrate 110 are formed in the first patterning treatment area. The second doped polysilicon sublayer 142 on the first patterning treatment area is oxidized on a side away from the silicon substrate 110 to form a patterned first mask layer of silicon oxide material. The laser activates the doping elements of the first doped polysilicon layer 140 and the doped silicon carbide layer 130 on the first patterning treatment area to increase the surface concentration, thereby forming the second doped polysilicon sublayer 142 and the first doped silicon carbide sublayer 131 with higher surface concentration.

[0120] The second doped polysilicon layer 170 is subjected to a second patterning process by using an ultraviolet laser, and a fourth doped polysilicon sublayer 172 is formed in the second patterning process area, and the portion of the second doped polysilicon layer 170 outside the second patterning process area is a third doped polysilicon sublayer 171. The laser activates the doping elements of the second doped polysilicon layer 170 in the second patterning process area to increase the surface concentration, thereby forming a fourth doped polysilicon sublayer 172 with a higher surface concentration.

[0121] The silicon substrate 110 is alkali washed to remove the first doped polysilicon layer 140 outside the coverage area of ​​the patterned first mask layer to form a patterned first doped polysilicon layer 140. The alkali-resistant doped silicon carbide layer 130 protects the first dielectric layer 120 during alkali washing; the second mask layer protects the second dielectric layer 160 and the second doped amorphous silicon layer during alkali washing.

[0122] A first anti-reflection layer 180 is deposited on the light receiving surface 111 .

[0123] A second anti-reflection layer 190 is deposited on the backlight surface 112 .

[0124] The first electrode 150 a is formed on the light receiving surface 111 , and the setting area of ​​the first electrode 150 a corresponds to the patterned area of ​​the first doped polysilicon layer 140 .

[0125] The second electrode 150 b is manufactured on the backlight surface 112 , and the second electrode 150 b is disposed in an area corresponding to the patterned area of ​​the fourth doped polysilicon sub-layer 172 .

[0126] The embodiment of the present application further discloses a photovoltaic module, comprising the solar cell 100 as described in the first aspect.

[0127] The technical solution of the utility model will be described below in conjunction with embodiments.

[0128] Example 1

[0129] Combination Figure 1 The solar cell 100 provided in this embodiment includes a silicon substrate 110, a first dielectric layer 120, a doped silicon carbide layer 130, a patterned first doped polysilicon layer 140, a first electrode 150a, a second dielectric layer 160, a second doped polysilicon layer 170, a second electrode 150b, a first anti-reflection layer 180 and a second anti-reflection layer 190.

[0130] The silicon substrate 110 is an N-type silicon substrate. The first dielectric layer 120 is a silicon oxide layer. The thickness of the first dielectric layer 120 is 1.8 nm.

[0131] The first dielectric layer 120 covers the light-receiving surface 111 of the silicon substrate 110. The doped silicon carbide layer 130 covers the side of the first dielectric layer 120 facing away from the silicon substrate 110. The first doped polysilicon layer 140 is disposed on the side of the doped silicon carbide layer 130 facing away from the silicon substrate 110. The first electrode 150a is disposed on the side of the first doped polysilicon layer 140 facing away from the silicon substrate 110, the first electrode 150a is in ohmic contact with the first doped polysilicon layer 140, and the patterned area of ​​the first doped polysilicon layer 140 corresponds to the area where the first electrode 150a is disposed. A portion of the first anti-reflection layer 180 is disposed on the side of the first doped polysilicon layer 140 facing away from the silicon substrate 110, the first electrode 150a penetrates the first anti-reflection layer 180 and is in ohmic contact with the first doped polysilicon layer 140, and a portion of the first anti-reflection layer 180 is disposed on the side of the doped silicon carbide layer 130 facing away from the silicon substrate 110. The first anti-reflection layer 180 is composed of a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer stacked in sequence away from the silicon substrate 110 , and the thickness of the first anti-reflection layer 180 is 90 nm.

[0132] The first doped polysilicon layer 140 includes a first doped polysilicon sublayer 141 and a second doped polysilicon sublayer 142 stacked in sequence away from the silicon substrate 110. The surface concentration of the second doped polysilicon sublayer 142 is greater than the surface concentration of the first doped polysilicon sublayer 141. The first electrode 150a is in ohmic contact with the second doped polysilicon sublayer 142. The first doped polysilicon layer 140 is a first P-type doped polysilicon layer. The surface concentration of the first doped polysilicon sublayer 141 is 9×10 19 atoms / cm 3 The thickness of the first doped polysilicon sublayer 141 is 30 nm. The surface concentration of the second doped polysilicon sublayer 142 is 3×10 20 atoms / cm 3 , the thickness of the second doped polysilicon sublayer 142 is 50 nm.

[0133] The portion of the doped silicon carbide layer 130 corresponding to the patterned area of ​​the first doped polysilicon layer 140 is the first doped silicon carbide sublayer 131 and the rest of the doped silicon carbide layer 130 is the second doped silicon carbide sublayer 132. The doping concentration of the first doped silicon carbide sublayer 131 is greater than the doping concentration of the second doped silicon carbide sublayer 132. The doped silicon carbide layer 130 is a P-type doped silicon carbide layer 130. The doping concentration of the first doped silicon carbide sublayer 131 is 7×10 19 atoms / cm 3 The doping concentration of the second doped silicon carbide sublayer 132 is 2×10 19 atoms / cm 3 The thickness of the doped silicon carbide layer 130 is 25 nm.

[0134] The second dielectric layer 160 covers the backlight surface 112 of the silicon substrate 110. The second doped polysilicon layer 170 covers the side of the second dielectric layer 160 facing away from the silicon substrate 110. The conductivity type of the second doped polysilicon layer 170 is opposite to the conductivity type of the first doped polysilicon layer 140. The second electrode 150b is arranged on the side of the second doped polysilicon layer 170 facing away from the silicon substrate 110, and the second electrode 150b is in ohmic contact with the second doped polysilicon layer 170. The second anti-reflection layer 190 is arranged on the side of the second doped polysilicon layer 170 facing away from the silicon substrate 110, and the second anti-reflection layer 190 is a silicon nitride layer with a thickness of 75nm. The second electrode 150b penetrates the second anti-reflection layer 190 and is in ohmic contact with the second doped polysilicon layer 170.

[0135] The second doped polysilicon layer 170 includes a third doped polysilicon sublayer 171 and a patterned fourth doped polysilicon sublayer 172. The third doped polysilicon sublayer 171 covers the side of the second dielectric layer 160 away from the silicon substrate 110, and the fourth doped polysilicon sublayer 172 is disposed on the side of the third doped polysilicon sublayer 171 away from the silicon substrate 110. The surface concentration of the fourth doped polysilicon sublayer 172 is greater than the surface concentration of the third doped polysilicon sublayer 171, and the patterned region of the fourth doped polysilicon sublayer 172 corresponds to the region where the second electrode 150b is disposed, and the second electrode 150b is in ohmic contact with the fourth doped polysilicon sublayer 172.

[0136] The second doped polysilicon layer 170 is a second N-type doped polysilicon layer. The surface concentration of the third doped polysilicon sublayer 171 is 4×10 20 atoms / cm 3 The thickness of the thinnest part is 55 nm. The surface concentration of the fourth doped polysilicon sublayer 172 is 1×10 21 atoms / cm 3 , thickness is 65nm.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A solar cell, characterized in that: include: Silicon substrate; a first dielectric layer, wherein the first dielectric layer covers the light-receiving surface of the silicon substrate; a doped silicon carbide layer, wherein the doped silicon carbide layer covers a side of the first dielectric layer facing away from the silicon substrate; A patterned first doped polysilicon layer, wherein the first doped polysilicon layer is disposed on a side of the doped silicon carbide layer away from the silicon substrate, and the first doped polysilicon layer and the doped silicon carbide layer have the same conductivity type; as well as A first electrode is disposed on a surface of the first doped polysilicon layer facing away from the silicon substrate, the first electrode is in ohmic contact with the first doped polysilicon layer, and a patterned area of ​​the first doped polysilicon layer corresponds to an area where the first electrode is disposed.

2. The solar cell according to claim 1, characterized in that: The first doped polysilicon layer includes a first doped polysilicon sublayer and a second doped polysilicon sublayer stacked in sequence away from the silicon substrate, the surface concentration of the second doped polysilicon sublayer is greater than the surface concentration of the first doped polysilicon sublayer, and the first electrode is in ohmic contact with the second doped polysilicon sublayer.

3. The solar cell according to claim 2, characterized in that: The first doped polysilicon layer is a first P-type doped polysilicon layer, and the surface concentration of the first doped polysilicon sublayer is 5×10 19 atoms / cm 3 ~1×10 20 atoms / cm 3 The thickness of the first doped polysilicon sublayer is 20 nm to 100 nm, and the surface concentration of the second doped polysilicon sublayer is 2×10 20 atoms / cm 3 ~5×10 20 atoms / cm 3 , the thickness of the second doped polysilicon sublayer is 20nm to 100nm; Or, the first doped polysilicon layer is a first N-type doped polysilicon layer, and the surface concentration of the first doped polysilicon sublayer is 3×10 20 atoms / cm 3 ~8×10 20 atoms / cm 3 The thickness of the first doped polysilicon sublayer is 20 nm to 50 nm, and the surface concentration of the second doped polysilicon sublayer is 9×10 20 atoms / cm 3 ~5×10 21 atoms / cm 3 , the thickness of the second doped polysilicon sublayer is 40nm to 70nm.

4. The solar cell according to claim 1, characterized in that: The solar cell also includes: a second dielectric layer, wherein the second dielectric layer covers the backlight surface of the silicon substrate; a second doped polysilicon layer, the second doped polysilicon layer covering a side of the second dielectric layer away from the silicon substrate; the conductivity type of the second doped polysilicon layer is opposite to the conductivity type of the first doped polysilicon layer; and A second electrode is disposed on a surface of the second doped polysilicon layer facing away from the silicon substrate, and the second electrode is in ohmic contact with the second doped polysilicon layer.

5. The solar cell according to claim 4, characterized in that: The second doped polysilicon layer includes a third doped polysilicon sublayer and a patterned fourth doped polysilicon sublayer, the third doped polysilicon sublayer covers a side of the second dielectric layer away from the silicon substrate, the fourth doped polysilicon sublayer is arranged on a side of the third doped polysilicon sublayer away from the silicon substrate, the surface concentration of the fourth doped polysilicon sublayer is greater than the surface concentration of the third doped polysilicon sublayer, the patterned area of ​​the fourth doped polysilicon sublayer corresponds to the setting area of ​​the second electrode, and the second electrode is in ohmic contact with the fourth doped polysilicon sublayer.

6. The solar cell according to claim 5, characterized in that: The second doped polysilicon layer is a second N-type doped polysilicon layer, and the surface concentration of the third doped polysilicon sublayer is 2×10 20 atoms / cm 3 ~8×10 20 atoms / cm 3 The thinnest thickness of the third doped polysilicon sublayer is 50nm to 150nm, and the surface concentration of the fourth doped polysilicon sublayer is 8×10 20 atoms / cm 3 ~5×10 21 atoms / cm 3 , the thickness of the fourth doped polysilicon sublayer is 50nm to 100nm; Or, the second doped polysilicon layer is a second P-type doped polysilicon layer, and the surface concentration of the third doped polysilicon sublayer is 5×10 18 atoms / cm 3 ~1×10 20 atoms / cm 3 The thinnest thickness of the third doped polysilicon sublayer is 60nm to 250nm, and the surface concentration of the fourth doped polysilicon sublayer is 1×10 20 atoms / cm 3 ~6×10 20 atoms / cm 3 , the thickness of the fourth doped polysilicon sublayer is 30nm to 150nm.

7. The solar cell according to any one of claims 4 to 6, characterized in that The solar cell also includes: a first anti-reflection layer, a portion of the first anti-reflection layer is disposed on a surface of the first doped polysilicon layer facing away from the silicon substrate, the first electrode penetrates the first anti-reflection layer and is in ohmic contact with the first doped polysilicon layer, and a portion of the first anti-reflection layer is disposed on a surface of the doped silicon carbide layer facing away from the silicon substrate; and A second anti-reflection layer is provided on a surface of the second doped polysilicon layer facing away from the silicon substrate, and the second electrode penetrates through the second anti-reflection layer and is in ohmic contact with the second doped polysilicon layer.

8. The solar cell according to claim 7, characterized in that: The silicon substrate is an N-type silicon substrate, and the resistivity of the silicon substrate is 0.3Ω·cm to 7Ω·cm; And / or, the first dielectric layer is a silicon oxide layer; And / or, the thickness of the first dielectric layer is 0.1 nm to 5 nm; And / or, the second dielectric layer is a silicon oxide layer; And / or, the thickness of the second dielectric layer is 0.1 nm to 5 nm; And / or, the first electrode is a silver electrode, an aluminum electrode or a nickel-copper electrode; And / or, the second electrode is a silver electrode, an aluminum electrode or a nickel-copper electrode; and / or, the first anti-reflection layer comprises at least one of a silicon nitride layer, a silicon oxynitride layer or a silicon oxide layer; And / or, the thickness of the first anti-reflection layer is 60nm to 130nm; and / or, the second anti-reflection layer comprises at least one of a silicon nitride layer, a silicon oxynitride layer or a silicon oxide layer; And / or, the second anti-reflection layer has a thickness of 60 nm to 130 nm.

9. The solar cell according to any one of claims 1 to 6, characterized in that: The portion of the doped silicon carbide layer corresponding to the patterned area of ​​the first doped polysilicon layer is a first doped silicon carbide sublayer, and the remaining portion of the doped silicon carbide layer is a second doped silicon carbide sublayer, and the doping concentration of the first doped silicon carbide sublayer is greater than the doping concentration of the second doped silicon carbide sublayer.

10. The solar cell according to claim 9, characterized in that: The doped silicon carbide layer is a P-type doped silicon carbide layer, and the doping concentration of the first doped silicon carbide sublayer is 5×10 19 atoms / cm 3 ~1×10 20 atoms / cm 3 , the doping concentration of the second doped silicon carbide sublayer is 1×10 18 atoms / cm 3 ~5×10 19 atoms / cm 3 , the thickness of the doped silicon carbide layer is 5nm to 50nm; Or, the doped silicon carbide layer is an N-type doped silicon carbide layer, and the doping concentration of the first doped silicon carbide sublayer is 3×10 20 atoms / cm 3 ~1×10 21 atoms / cm 3 , the doping concentration of the second doped silicon carbide sublayer is 1×10 20 atoms / cm 3 ~7×10 20 atoms / cm 3 The thickness of the doped silicon carbide layer is 5 nm to 50 nm, wherein the doping type of the doped silicon carbide layer is the same as the doping type of the silicon substrate.

11. A photovoltaic module, characterized in that: Comprising the solar cell according to any one of claims 1 to 10.

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