Heterojunction solar cell and manufacturing method

Abstract

The present application provides a heterojunction solar cell and a manufacturing method thereof, which comprises an n-type or p-type silicon sheet that is n-type or p-type doped and has a front and a back surface facing each other, a first passivation layer and a second passivation layer that are sequentially provided on the front surface of the n-type or p-type silicon sheet, a third passivation layer and a fourth passivation layer that are sequentially provided on the back surface of the n-type or p-type silicon sheet, and a microcrystalline or nanocrystalline silicon carbide layer that is provided on one side of the fourth passivation layer away from the n-type or p-type silicon sheet, the microcrystalline or nanocrystalline silicon carbide layer forms a pn junction with the n-type or p-type silicon sheet through n-type or p-type doping, and the atomic percentage of carbon element in the silicon carbide layer is greater than the atomic percentage of oxygen element. The heterojunction solar cell of the present application enhances the performance of the solar cell, and the carbon element and the oxygen element have a fixing effect on the hydrogen element in the silicon carbide layer, which is advantageous in reducing the loss of hydrogen element.

Description

[Technical field]

[0001] This application relates generally to the field of photovoltaics, and more particularly to heterojunction solar cells and methods of manufacture. [Background technology]

[0002] Silicon-based heterojunction cells are one of the currently mainstream high-efficiency solar cell technologies, with the advantages of simple structure, high conversion efficiency, and low temperature coefficient, and are one of the important directions for the development of solar cells. The structure and process of silicon-based heterojunction cells are relatively simple, which is based on an n-type or p-type doped silicon substrate, and an intrinsic amorphous silicon layer, a p- or n-type amorphous silicon layer are formed on one side of the silicon substrate, and an intrinsic amorphous silicon layer, an n-type amorphous silicon layer are formed on the other side of the silicon substrate. Here, the p- or n-type amorphous silicon layer forms a pn junction with the n- or p-type doped silicon substrate.

[0003] In the silicon-based heterojunction cell in the prior art, the p-type doping layer was amorphous silicon doped with boron element, but the doping amount was limited to an upper limit, leading to low doping efficiency of the p-type doping layer, weakening the electric field of the pn junction on the back of the cell, increasing the recombination of photocarriers, and ultimately reducing the cell efficiency.

[0004] Therefore, how to increase the upper limit of doping of dopants and improve the cell efficiency is an issue that needs to be solved urgently. Summary of the Invention [Problem to be solved by the invention]

[0005] The technical problem to be solved by the present application is to provide a heterojunction solar cell and a manufacturing method thereof, which have the advantages of a high doping upper limit and high cell efficiency. [Means for solving the problem]

[0006] In order to solve the above technical problems, the present application adopts a technology for a heterojunction solar cell comprising: a silicon substrate doped with n-type or p-type and having a front and a back surface facing each other; a first passivation layer and a second passivation layer sequentially provided on the front surface of the silicon substrate; a third passivation layer and a fourth passivation layer sequentially provided on the back surface of the silicon substrate; and a silicon carbide layer provided on one surface of the fourth passivation layer away from the silicon substrate, the silicon carbide layer being doped with n-type or p-type to form a pn junction with the silicon substrate, and an atomic percentage of carbon elements in the silicon carbide layer being greater than the atomic percentage of oxygen elements.

[0007] In one embodiment of the present application, the first passivation layer is hydrogenated amorphous silicon oxide and the second passivation layer is hydrogenated nanocrystalline silicon.

[0008] In one embodiment of the present application, the third passivation layer is hydrogenated amorphous silicon and the fourth passivation layer is hydrogenated nanocrystalline silicon.

[0009] In one embodiment of the present application, the silicon substrate is n-type doped and the silicon carbide layer is p-type doped.

[0010] In one embodiment of the present application, the semiconductor device further includes a fifth passivation layer provided on a surface of the second passivation layer away from the silicon substrate, and the material of the fifth passivation layer is hydrogenated n-type microcrystalline or nanocrystalline silicon carbide.

[0011] In one embodiment of the present application, the semiconductor device further includes a first transparent conductive oxide thin film provided on a surface of the fifth passivation layer away from the silicon substrate, and a second transparent conductive oxide thin film provided on a surface of the fourth passivation layer away from the silicon substrate.

[0012] In one embodiment of the present application, the semiconductor device further includes an anti-reflection thin film provided on a surface of the first transparent conductive oxide thin film that faces away from the silicon substrate.

[0013] In one embodiment of the present application, the device further includes a first electrode and a second electrode in contact with the first transparent conductive oxide thin film and the second transparent conductive oxide thin film, respectively, and the first electrode and / or the second electrode is manufactured by an electroplating or chemical plating method.

[0014] In one embodiment of the present application, the atomic percentage of the carbon element in the silicon carbide layer is 7 times or more than the atomic percentage of the oxygen element.

[0015] In order to solve the above technical problems, the present application further provides a method for manufacturing a heterojunction solar cell, comprising the steps of: providing an n-type or p-type silicon sheet having a front and a back surface opposite to each other; sequentially forming a first passivation layer and a second passivation layer on the front surface of the n-type or p-type silicon sheet; sequentially forming a third passivation layer and a fourth passivation layer on the back surface of the n-type or p-type silicon sheet; and forming a silicon carbide layer on a surface of the fourth passivation layer away from the n-type or p-type silicon sheet, wherein the silicon carbide layer is n-type or p-type doped to form a pn junction with the n-type or p-type silicon sheet, and the atomic percentage of carbon element in the silicon carbide layer is greater than the atomic percentage of oxygen element.

[0016] The heterojunction solar cell of the present invention employs a doped silicon carbide layer and an n-type or p-type silicon sheet to combine a pn junction, thereby increasing the upper doping limit of the dopant in the silicon sheet layer, thereby improving the performance of the solar cell; and the carbon and oxygen elements have a fixing effect on the hydrogen elements in the silicon carbide layer, which is advantageous in reducing the loss of hydrogen elements.

[0017] In order to make the above objects, features, and advantages of the present application more clearly understandable, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a cross-sectional schematic diagram of a heterojunction solar cell according to an embodiment of the present application. [Diagram 2] 1 is an exemplary flow chart of a method for manufacturing a heterojunction solar cell according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] In order to make the above objects, features, and advantages of the present application more clearly understandable, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0020] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application; however, the present application may also be practiced in other ways other than as described herein, and therefore the present application is not limited to the specific embodiments disclosed below.

[0021] As used herein and in the claims, unless the context clearly indicates otherwise, terms such as "a," "one," "a kind," and / or "the" do not specifically refer to the singular but may include the plural. In general, the terms "comprising" and "including" are used only to indicate the inclusion of specifically identified steps and elements, and do not constitute an exclusive list of steps and elements, and a method or apparatus may include other steps or elements.

[0022] It should also be explained that the use of terms such as "first" and "second" to limit the components is merely to facilitate distinction between corresponding components, and that unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limitations on the scope of protection of the present application. Furthermore, although the terms used in the present application are selected from known terms, some of the terms described in the specification of the present application are selected by the applicant at his / her own discretion, and their detailed meanings will be explained in the relevant parts of the description of this specification. It is also required to understand the present application not only based on the actual terms used but also on the meanings contained in each term.

[0023] In the present application, flowcharts are used to describe the operations performed by the system according to the embodiment of the present application. It will be understood that it is intended that the above or following operations are not necessarily performed in exact order. In contrast, various steps may be processed in reverse order or simultaneously. Concurrently, other operations may be added to these processes, or operations of one or more steps may be deleted from these processes.

[0024] The pn junction in a heterojunction solar cell consists of a doped silicon substrate and a material layer on one side of the silicon substrate, doped with a dopant of opposite polarity to that of the dopant in the silicon substrate. In the prior art, the upper doping limit in this material layer is low. The heterojunction solar cell of the present application has the advantage of a high upper doping limit.

[0025] Next, the heterojunction solar cell of the present application will be described with reference to specific embodiments.

[0026] 1 is a cross-sectional schematic diagram of a heterojunction solar cell according to an embodiment of the present application. As shown in FIG. 1, the heterojunction solar cell 100 includes a silicon substrate 110, a first passivation layer 120, a second passivation layer 130, a third passivation layer 140, a fourth passivation layer 150, and a silicon carbide layer 160.

[0027] Specifically, as shown in Fig. 1, the silicon substrate 110 is subjected to n-type or p-type doping treatment. The material of the silicon substrate 110 includes one or more of monocrystalline silicon and polycrystalline silicon. Through the doping process, the monocrystalline silicon may be doped with phosphorus element (P) to form an n-type silicon substrate 110, or may be doped with boron element (B) to form a p-type silicon substrate 110. It is understood that the doping element in the silicon substrate 110 is not limited to the above-mentioned phosphorus element and boron element, but may be other elements capable of forming n-type and p-type silicon substrates.

[0028] Furthermore, the silicon substrate 110 is not limited to a particular size and shape. The silicon substrate 110 may be a circular substrate having a 200 mm diameter, a 300 mm diameter, or other diameters such as 450 mm. If desired, the silicon substrate 110 may be a polygonal, square, rectangular, curved, or other non-circular workpiece, such as a polygonal workpiece.

[0029] As shown in FIG. 1, the silicon substrate 110 has a front surface 110a and a back surface 110b that face each other along a thickness direction D1, and the front surface 110a refers to the surface of the silicon substrate 110 facing upward in FIG.

[0030] In one embodiment, the silicon substrate 110 is an n-type doped silicon substrate. For convenience of explanation, unless otherwise specified, all silicon substrates 110 described below are n-type doped silicon substrates.

[0031] 1, the first passivation layer 120 is provided on the front surface 111a of the silicon substrate 110, and the second passivation layer 130 is provided on one surface away from the silicon substrate 110 along the thickness direction D1 of the first passivation layer 120, that is, the first passivation layer 120 and the second passivation layer 130 are sequentially provided on the front surface 110a of the silicon substrate 110. The method of sequentially forming the first passivation layer 120 and the second passivation layer 130 on the front surface 110a of the silicon substrate 110 is to use VHF plasma enhanced chemical vapor deposition (VHF-PECVD) to sequentially form the first passivation layer 120 and the second passivation layer 130 on the front surface 110a of the silicon substrate 110, where the thickness of the first passivation layer 120 is 0.8-1.5 nm, and the thickness of the second passivation layer 130 is 3-4 nm. In some embodiments, the method further includes performing a damage removal cleaning and flocking process on the silicon substrate 110 before forming the first passivation layer 120, where the damage removal cleaning can remove damage on the front surface 110a and back surface 110b of the silicon substrate 110, and the flocking process can form pyramid piles to reduce the reflectivity of the silicon substrate 110 to light.

[0032] In one embodiment, the first passivation layer is hydrogenated amorphous silicon oxide, and the second passivation layer is hydrogenated nanocrystalline silicon. Compared with monocrystalline silicon oxide and amorphous silicon oxide, adopting hydrogenated amorphous silicon oxide for the first passivation layer is advantageous to increase the content of hydrogen element in the first passivation layer, thus improving the passivation performance of the first passivation layer and reducing the growth probability of interface epitaxial crystals, thereby increasing the photogenerated current density of the battery. In addition, the oxygen element in the first passivation layer can form hydrogen bonds with the hydrogen element, thereby preventing the hydrogen element from diffusing from the first passivation layer. The electrical conductivity of the second passivation layer using nanocrystalline silicon is better than that of the second passivation layer using amorphous silicon, which can reduce the resistivity of the second passivation layer and increase the fill factor (FF) of the battery. The combination of the first passivation layer and the second passivation layer can ensure that the conductivity of the passivation layer meets the requirements while obtaining an excellent passivation effect. In some embodiments, the size of the nanocrystalline silicon in the second passivation layer is 2-5 nm, and the crystallization rate of the second passivation layer is 10%-70%. Here, "hydrogenation" refers to the introduction of hydrogen atoms (H) into a material layer (e.g., the first passivation layer, the second passivation layer), and these hydrogen atoms can neutralize dangling bonds and defects in the material layer, thereby reducing carrier complexation and thus improving the efficiency of the battery. Except as otherwise described, the above description of "hydrogenation" also applies to the following description, and will not be repeated.

[0033] In another embodiment, as shown in FIG. 1, the solar cell 100 further comprises a fifth passivation layer 170 provided on one side of the second passivation layer 130 away from the silicon substrate 110, the material of the fifth passivation layer 170 is hydrogenated n-type microcrystalline or nanocrystalline silicon carbide, and when the silicon carbide in the fifth passivation layer 170 is microcrystalline silicon carbide, its crystal grain size is 10-100 nm. The atomic percentage of oxygen element in the fifth passivation layer can be greater than, equal to, or smaller than the atomic percentage of carbon element. The fifth passivation layer 170 has the role of transporting electrons and electric field passivation, and is therefore favorable to improving the performance of the cell.

[0034] In some embodiments, the method for manufacturing the fifth passivation layer 170 comprises depositing the fifth passivation layer 170 on the side of the second passivation layer 130 away from the silicon substrate 110 by using VHF plasma enhanced chemical vapor deposition (VHF-PECVD), and the thickness of the fifth passivation layer 170 is 10-20 nm. In the previous embodiment, the second passivation layer 130 uses hydrogenated nanocrystalline silicon, and the hydrogenated nanocrystalline silicon at the interface between the second passivation layer 130 and the fifth passivation layer 170 can be a seed layer of n-type microcrystalline or nanocrystalline silicon carbide in the fifth passivation layer, which is advantageous for increasing the crystallization rate of the fifth passivation layer.

[0035] 1, the third passivation layer 140 is located on the back surface 110b of the silicon substrate 110, and the fourth passivation layer 150 is formed on one side of the third passivation layer 140 away from the silicon substrate 110, i.e., the third passivation layer 140 and the fourth passivation layer 150 are sequentially formed on the back surface 110b of the silicon substrate 110. In some embodiments, the manufacturing methods of the third passivation layer 140 having a thickness of 5-10 nm and the fourth passivation layer 150 having a thickness of 3-4 nm may be the same as those of the first passivation layer 120 and the second passivation layer 130.

[0036] In one embodiment, the third passivation layer is hydrogenated amorphous silicon, and the fourth passivation layer is hydrogenated nanocrystalline silicon. Using amorphous silicon helps to increase the content of hydrogen element in the third passivation layer, and can enhance the passivation effect, compared with using hydrogenated nanocrystalline silicon as the material of the third passivation layer. Since the high-concentration hydrogen plasma in the process has an etching effect on the amorphous silicon, the thickness of the third passivation layer may be smaller than the designed thickness, so nanocrystalline silicon is adopted as the material of the fourth passivation layer, thus playing the role of auxiliary passivation, thereby ensuring the passivation effect. In some embodiments, the size of the nanocrystalline silicon of the fourth passivation layer is 2-5 nm, and the crystallization rate of the fourth passivation layer is 10%-70%.

[0037] As still shown in FIG. 1, the silicon carbide layer 160 is provided on one side of the fourth passivation layer 150 away from the silicon substrate 110. Here, the silicon carbide layer is n-type or p-type doped to form a pn junction with the silicon substrate 110, and the atomic percentage of carbon elements in the silicon carbide layer is greater than the atomic percentage of oxygen elements. As described above, the silicon substrate 110 may be an n-type silicon substrate or a p-type silicon substrate. When the silicon substrate 110 is an n-type silicon substrate, the silicon carbide layer 160 is a p-type doped silicon carbide layer that forms a pn junction with the silicon substrate 110, and in the opposite case, the silicon carbide layer 160 is an n-type doped silicon carbide layer. The silicon carbide layer 160 described below is p-type doped for convenience of explanation. In some embodiments, the method of forming the silicon carbide layer 160 is the same as that of the fourth passivation layer, the thickness of the silicon carbide layer 160 is 5-10 nm, and the silicon carbide may be microcrystalline silicon carbide or nanocrystalline silicon carbide. If the silicon carbide is microcrystalline silicon carbide, its particle size is 10-100 nm, and if the silicon carbide is nanocrystalline silicon carbide, its particle size is 2-5 nm.

[0038] In the prior art, it was common to obtain a p-type doped layer by doping amorphous silicon with boron element, but the doping activation rate was low, so the doping amount had to be increased to increase the doping activation rate, which could result in overdoping and the generation of a dead layer. In addition, when a p-type doped layer is obtained by doping microcrystalline silicon with boron element, the upper limit of doping of boron element in microcrystalline silicon is low. The present application can effectively solve the above problem by doping silicon carbide. Since carbon is a chemical element of the same group as silicon, it can be efficiently incorporated into the silicon thin film structure during the manufacturing process, and a stable carbon-silicon compound can be formed, thereby improving the optical band gap of the solar cell. In addition, the optical band gap can be further improved by adding oxygen element, and since both oxygen element and carbon element have the effect of fixing hydrogen, the increase in the internal defect density of the silicon carbide layer 160 due to the loss of hydrogen element can be reduced. At the same time, the doping upper limit of silicon carbide is high, the dead layer is not easily formed, and the doping activation concentration can be increased by microcrystallization, so that the performance of silicon-based heterojunction batteries can be improved by using p-type hydrogenated microcrystalline silicon carbide. After adopting silicon carbide as the p-type layer, the present application further restricts that the content of carbon element in the silicon carbide layer is higher than the content of oxygen element, thus allowing more carbon and silicon bonds to be formed in the silicon carbide layer; on the one hand, compared with silicon oxide, silicon carbide has a wider band gap and a higher doping upper limit, which can improve the doping amount and the performance of the solar cell; on the other hand, when the doping element in the silicon carbide layer is boron element, the oxygen element in the silicon carbide layer can combine with boron element to generate a boron-oxygen pair, which can cause attenuation in the solar cell, so reducing the content of oxygen element is favorable to reducing the bond between boron element and oxygen element.In some other embodiments, the atomic percentage of carbon element in the silicon carbide layer is 7 times or more than the atomic percentage of oxygen element, which ensures that the doping amount in the silicon carbide layer meets the requirements.

[0039] In one embodiment, the solar cell further comprises a first transparent conductive oxide thin film and a second transparent conductive oxide thin film. As shown in FIG. 1, the first transparent conductive oxide thin film 180 is provided on one side of the fifth passivation layer 170 away from the silicon substrate 110, and the second transparent conductive oxide thin film 190 is provided on one side of the silicon carbide layer 160 away from the silicon substrate 110. In some embodiments, the method for manufacturing the transparent conductive oxide thin film comprises using physical vapor deposition (PVD) and reactive plasma deposition (RPD), where the thickness of the first transparent conductive oxide thin film 180 and the second transparent conductive oxide thin film 190 is 60-80 nm, and it should be noted that the thickness of the first transparent conductive oxide thin film 180 and the second transparent conductive oxide thin film 190 may be equal or unequal.

[0040] As shown with reference to FIG. 1, in another embodiment, the solar cell 100 further includes a first electrode 211 and a second electrode 212. Here, the first electrode 211 and the second electrode 212 are in contact with a first transparent conductive oxide thin film 180 and a second transparent conductive oxide thin film 190, respectively. The first transparent conductive oxide thin film 180 can prevent the first electrode 211 from directly contacting the fifth passivation layer 170, and the second transparent conductive oxide thin film 190 can prevent the second electrode 212 from directly contacting the silicon carbide layer 160, thereby avoiding a significant increase in resistance.

[0041] In some embodiments, the method of manufacturing the first and second electrodes comprises an electroplating or chemical plating method, and the material of the first and second electrodes comprises one or more of metallic copper, metallic aluminum, metallic nickel, and metallic tin. Compared to using screen-printed silver electrodes, the manufacturing of non-silver electrodes by electroplating or chemical plating has the advantage of lower cost.

[0042] As shown in FIG. 1, in one embodiment, the solar cell 100 further includes an anti-reflection thin film 220 provided on one side of the first transparent conductive oxide thin film 180 away from the silicon substrate 110. In some embodiments, the number of anti-reflection thin films is not limited to one layer as shown in FIG. 1, and may be any number, such as two layers or three layers. Materials for the anti-reflection thin film include, but are not limited to, one or more of silicon nitride, silicon oxide, magnesium fluoride, and titanium oxide. The anti-reflection thin film 220 can reduce the reflection of the solar cell against incident light and improve the utilization rate of the cell against the incident light.

[0043] The solar cell in the above embodiment adopts a doped silicon carbide layer and a silicon substrate to combine a pn junction, and specifies that the atomic percentage of carbon element in the silicon carbide layer is greater than that of oxygen element, thereby increasing the upper doping limit of the dopant in the silicon carbide layer, thereby improving the performance of the solar cell; and the carbon and oxygen elements have a fixing effect on the hydrogen element in the silicon carbide layer, which is advantageous in reducing the loss of hydrogen element.

[0044] Another aspect of the present application also proposes a method for manufacturing a heterojunction solar cell. Referring to an exemplary flow chart of a method for manufacturing a heterojunction solar cell in an embodiment of the present application shown in Fig. 2, as shown in Fig. 1, the method includes the following steps:

[0045] Step S110: Provide an n-type or p-type silicon sheet 110 having opposing front and back surfaces 110a and 110b.

[0046] Step S120: A first passivation layer 120 and a second passivation layer 130 are sequentially formed on the front surface 110a of the n-type or p-type silicon sheet 110.

[0047] Step S130: A third passivation layer 140 and a fourth passivation layer 150 are sequentially formed on the rear surface 110b of the n-type or p-type silicon sheet 110.

[0048] Step S140: On one side of the fourth passivation layer 150 away from the n-type or p-type silicon sheet 110, a silicon carbide layer 160 is formed which is n-type or p-type doped to form a pn junction with the n-type or p-type silicon sheet 110, and in which the atomic percentage of carbon elements in the silicon carbide layer 160 is greater than the atomic percentage of oxygen elements.

[0049] For other details of the manufacturing method of the heterojunction solar cell of the present application, reference can be made to the above related descriptions, and a detailed description will not be given here.

[0050] The manufacturing method in the above embodiment adopts a doped carbon oxide layer and an n-type or p-type silicon sheet to combine a pn junction, and specifies that the atomic percentage of carbon atoms in the silicon carbide layer is greater than that of oxygen atoms, thereby increasing the upper doping limit of the dopant in the silicon carbide layer and thereby improving the performance of the solar cell; and the carbon and oxygen elements have a fixing effect on the hydrogen elements in the silicon carbide layer, which is advantageous in reducing the loss of hydrogen elements.

[0051] Although the basic concepts have been described above, it is obvious to those skilled in the art that the above disclosure is merely an example and is not intended to limit the present application. Although not expressly stated herein, those skilled in the art may make various modifications, improvements, and amendments to the present application. Such modifications, improvements, and amendments are proposed in this application and therefore fall within the spirit and scope of the exemplary embodiments of the present application.

[0052] At the same time, the present application uses certain terms to describe the embodiments of the present application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to features, configurations, or characteristics associated with at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "one embodiment" or "one alternative embodiment" mentioned more than once in different places in this specification do not necessarily refer to the same embodiment. Furthermore, some features, configurations, or characteristics in one or more embodiments of the present application may be combined as appropriate.

[0053] In some embodiments, numbers are used to describe the number of components, attributes, but it should be understood that the numbers to describe such embodiments are modified in some instances using the modifiers "about", "approximately", or "approximately". Unless otherwise specified, "about", "approximately", or "approximately" means that the numerical value is allowed to vary by ±20%. Thus, in some embodiments, the numerical parameters used in the specification and claims are approximations, and these approximations may be modified depending on the characteristics required for each embodiment. In some embodiments, the numerical parameters should be calculated with a given number of significant digits and adopt a common method of conserving digits. In some embodiments of the present application, the numerical fields and parameters used to determine the breadth of their ranges are approximations, but in certain embodiments, such numerical values ​​are set as precisely as possible within the ranges possible.

Claims

1. a silicon substrate which is n-type or p-type doped and has opposing front and back surfaces; a first passivation layer and a second passivation layer sequentially provided on a front surface of the silicon substrate; a third passivation layer and a fourth passivation layer sequentially provided on a back surface of the silicon substrate; a silicon carbide layer provided on a surface of the fourth passivation layer away from the silicon substrate; The silicon carbide layer is doped with n-type or p-type doping to form a pn junction with the silicon substrate, and the atomic percentage of carbon elements in the silicon carbide layer is greater than the atomic percentage of oxygen elements.

2. 2. The solar cell of claim 1, wherein the first passivation layer is hydrogenated amorphous silicon oxide and the second passivation layer is hydrogenated nanocrystalline silicon.

3. 2. The solar cell of claim 1, wherein the third passivation layer is hydrogenated amorphous silicon and the fourth passivation layer is hydrogenated nanocrystalline silicon.

4. 2. The solar cell of claim 1, wherein the silicon substrate is n-type doped and the silicon carbide layer is p-type doped.

5. 5. The solar cell of claim 4, further comprising a fifth passivation layer provided on a surface of the second passivation layer away from the silicon substrate, the material of the fifth passivation layer being hydrogenated n-type microcrystalline or nanocrystalline silicon carbide.

6. 6. The solar cell according to claim 5, further comprising a first transparent conductive oxide thin film provided on a surface of the fifth passivation layer away from the silicon substrate, and a second transparent conductive oxide thin film provided on a surface of the fourth passivation layer away from the silicon substrate.

7. The solar cell according to claim 6 , further comprising an anti-reflection thin film provided on a surface of the first transparent conductive oxide thin film that faces away from the silicon substrate.

8. 7. The solar cell of claim 6, further comprising a first electrode and a second electrode in contact with the first transparent conductive oxide thin film and the second transparent conductive oxide thin film, respectively, wherein the first electrode and / or the second electrode is manufactured by an electroplating or chemical plating method.

9. 2. The solar cell according to claim 1, wherein the atomic percentage of the carbon element in the silicon carbide layer is 7 times or more the atomic percentage of the oxygen element.

10. providing an n-type or p-type silicon sheet having opposing front and back surfaces; sequentially forming a first passivation layer and a second passivation layer on a front surface of the n-type or p-type silicon sheet; Sequentially forming a third passivation layer and a fourth passivation layer on a rear surface of the n-type or p-type silicon sheet; forming a silicon carbide layer on a surface of the fourth passivation layer facing away from the n-type or p-type silicon sheet; The silicon carbide layer is doped with n-type or p-type doping to form a pn junction with an n-type or p-type silicon sheet, and the atomic percentage of carbon elements in the silicon carbide layer is greater than the atomic percentage of oxygen elements.

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