WO2021068307A1 - Solar cell and manufacturing method therefor - Google Patents

Abstract

A solar cell and a manufacturing method therefor. When a second polysilicon layer provided with a polysilicon spacer region, and a first doped polysilicon region and a second doped polysilicon region, the polarities of which are the opposite of each other, is formed, the first doped polysilicon region and the second doped polysilicon region are both formed by means of laser heating. The whole manufacturing process does not require the step of patterning any layer and also does not require an additional high-temperature treatment process, such that the manufacturing process for solar cells is simplified, thereby improving the production efficiency of solar cells.

Description

Solar cell and manufacturing method thereof

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on October 10, 2019, the application number is 201910959310.9, and the invention title is "a solar cell and its manufacturing method", the entire content of which is incorporated into this application by reference in.

Technical field

This application relates to the technical field of solar cells, in particular to a solar cell and a manufacturing method thereof.

Background technique

The back-contact solar cell using passivation contact technology has no metal grid lines on the front side, which can not only avoid the current loss due to the shielding of the metal grid lines, but also prevent the metal grid lines from burning through the paste when the metal grid lines are sintered. The contact between the chemical layer and the silicon substrate produces surface recombination, which leads to a decrease in the opening voltage of the solar cell. Therefore, the back contact solar cell has become a research hotspot.

The back-contact solar cell containing the polysilicon layer combined with N-type polysilicon and P-type polysilicon minimizes the surface recombination of the contact area between the metal gate line and the silicon substrate, and increases the opening voltage. There needs to be an insulating region between the N-type polysilicon and the P-type polysilicon. The insulating region can be a channel or undoped polysilicon whose resistance is increased by oxygen ion implantation. When the insulating region is a channel, the process of patterning the doped layer when forming N-type polysilicon and P-type polysilicon is very complicated; when the insulating region is undoped polysilicon with increased resistance, it needs to be used In the ion implantation method, a mask material is required to form a resistive spacer in a specific pattern. It also introduces additional mask layers and patterning steps required by the mask layer. In addition, the ion implantation method requires a high-temperature treatment process. As a result, the preparation process of the existing back-contact solar cell is very complicated and cumbersome, and the production efficiency of the solar cell is low.

Therefore, how to simplify the manufacturing process of solar cells is an urgent technical problem to be solved by those skilled in the art.

Summary of the invention

The purpose of this application is to provide a solar cell and a manufacturing method thereof to simplify the manufacturing process of the solar cell.

In order to solve the above technical problems, this application provides a solar cell manufacturing method, including:

Form a diffusion layer on the front side of the silicon substrate;

Forming a dielectric layer on the back surface of the silicon substrate;

Forming a polysilicon layer on the lower surface of the dielectric layer;

Forming a first type doped layer on the lower surface of the polysilicon layer;

The first predetermined area of the first type doped layer is heated by laser heating, so that the area corresponding to the first predetermined area of the polysilicon layer forms a first doped polysilicon area, and a first polysilicon area is obtained. Crystalline silicon layer;

Removing the first type doped layer;

Forming a second-type doped layer on the lower surface of the first polysilicon layer, and the second-type doped layer and the first-type doped layer have opposite polarities;

Laser heating is used to heat the second predetermined area of the second type doped layer, so that the area corresponding to the first polysilicon layer and the second predetermined area forms a second doped polysilicon area, Obtaining a second polysilicon layer, and the second polysilicon layer has a polysilicon spacer between the first doped polysilicon region and the second doped polysilicon region;

Removing the second type doped layer;

Forming a first passivation layer on the lower surface of the second polysilicon layer;

Forming an anti-reflection layer on the upper surface of the diffusion layer;

A metal electrode is formed on the lower surface of the first passivation layer.

Optionally, forming a first type doped layer on the lower surface of the polysilicon layer includes:

The first-type doped layer is formed on the lower surface of the polysilicon layer by any one of atmospheric pressure chemical vapor deposition method, screen printing method, inkjet method, and spin coating method.

Optionally, forming a diffusion layer on the front surface of the silicon substrate includes:

Using thermal diffusion or ion implantation, the diffusion layer is formed on the front surface of the silicon substrate.

Optionally, the forming a dielectric layer on the back surface of the silicon substrate includes:

The dielectric layer is formed on the back surface of the silicon substrate by any one of a chemical vapor deposition method, a high temperature thermal oxygen oxidation method, and a nitric acid oxidation method.

Optionally, before forming the polysilicon layer on the back side of the silicon substrate, the method further includes:

Texturing the silicon substrate.

Optionally, before the anti-reflection layer is formed on the upper surface of the diffusion layer, the method further includes:

Forming a second passivation layer on the upper surface of the diffusion layer;

Correspondingly, forming an anti-reflection layer on the upper surface of the diffusion layer includes:

The anti-reflection layer is formed on the upper surface of the second passivation layer.

This application also provides a solar cell, including:

Silicon substrate

A dielectric layer on the back of the silicon substrate;

The second polysilicon layer is located on the lower surface of the dielectric layer, and the second polysilicon layer includes a first doped polysilicon region, a second doped polysilicon region, and is located on the first doped polysilicon region. The polysilicon spacers between the second doped polysilicon regions, wherein the first doped polysilicon regions and the second doped polysilicon regions have opposite polarities, and the first doped polysilicon regions and the The second doped polysilicon regions are all obtained by laser heating;

A first passivation layer located on the lower surface of the second polysilicon layer;

A metal electrode located on the lower surface of the first passivation layer;

A diffusion layer located on the front side of the silicon substrate;

An anti-reflection layer located on the upper surface of the diffusion layer.

Optionally, the dielectric layer is any one of the following:

Silicon dioxide dielectric layer, silicon nitride dielectric layer, aluminum oxide dielectric layer, hafnium oxide dielectric layer.

Optionally, the thickness of the dielectric layer ranges from 1 nanometer to 4 nanometers, inclusive.

Optionally, it also includes:

A second passivation layer located between the diffusion layer and the anti-reflection layer.

The solar cell and its manufacturing method provided by this application include forming a diffusion layer on the front surface of a silicon substrate; forming a dielectric layer on the back surface of the silicon substrate; forming a polysilicon layer on the lower surface of the dielectric layer; A first type doped layer is formed on the lower surface of the polysilicon layer; a laser heating method is used to heat the first preset area of the first type doped layer, so that the polysilicon layer corresponds to the first preset area A first doped polysilicon region is formed in the region to obtain a first polysilicon layer; the first type doped layer is removed; a second type doped layer is formed on the lower surface of the first polysilicon layer, and the The second type doped layer has the opposite polarity to the first type doped layer; laser heating is used to heat the second predetermined area of the second type doped layer to make the first polysilicon The region corresponding to the second predetermined region forms a second doped polycrystalline silicon region to obtain a second polycrystalline silicon layer, and the second polycrystalline silicon layer has a shape located between the first doped polycrystalline silicon region and the Polysilicon spacers between the second doped polysilicon regions; removing the second type doped layer; forming a first passivation layer on the lower surface of the second polysilicon layer; on the upper surface of the diffusion layer Forming an anti-reflection layer; forming a metal electrode on the lower surface of the first passivation layer.

It can be seen that the solar cell and its manufacturing method in the present application adopt laser heating when forming a second polysilicon layer with polysilicon spacers, first doped polysilicon regions with opposite polarities, and second doped polysilicon regions. The first doped polycrystalline silicon region and the second doped polycrystalline silicon region are formed in this way. The whole manufacturing process does not require the step of patterning any layer, nor does it require additional high-temperature processing, which simplifies the solar cell manufacturing process, thereby improving the solar cell Production efficiency.

Description of the drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are merely For some of the embodiments of the present application, for those of ordinary skill in the art, other drawings may be obtained based on these drawings without creative work.

FIG. 1 is a flowchart of a method for manufacturing a solar cell provided by an embodiment of the application;

2 to 11 are process flow diagrams of a solar cell manufacturing method provided by embodiments of the application;

FIG. 12 is a flowchart of a method for manufacturing a solar cell according to an embodiment of the application;

FIG. 13 is a schematic structural diagram of a solar cell provided by an embodiment of the application;

FIG. 14 is a schematic structural diagram of another solar cell provided by an embodiment of the application.

Detailed ways

In order to enable those skilled in the art to better understand the solution of the application, the application will be further described in detail below with reference to the accompanying drawings and specific implementations. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of this application.

In the following description, many specific details are explained in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described here, and those skilled in the art can do so without departing from the connotation of the present invention. Similar promotion, therefore, the present invention is not limited by the specific embodiments disclosed below.

As mentioned in the background art section, when preparing a back-contact solar cell containing a polysilicon layer combined with N-type polycrystalline silicon and P-type polycrystalline silicon, an insulating region needs to be formed between the N-type polycrystalline silicon and the P-type polycrystalline silicon, regardless of whether the insulating region is a channel or The undoped polysilicon after increasing the resistance requires a patterning process, which is very complicated, and even requires a high-temperature process, which further increases the complexity and makes the production efficiency of the solar cell low.

In view of this, the present application provides a solar cell manufacturing method. Please refer to FIG. 1. FIG. 1 is a flowchart of a solar cell manufacturing method provided by an embodiment of the application. The method includes:

Step S101: forming a diffusion layer on the front surface of the silicon substrate.

Referring to FIG. 2, a diffusion layer 2 is formed on the front surface of the silicon substrate 1.

It should be noted that the front side of the silicon substrate is the surface facing the sun, and the back side is the surface facing away from the sun.

It should also be noted that the method for forming the diffusion layer is not specifically limited in this embodiment, and it depends on the situation. For example, a thermal diffusion method, or ion implantation method, or laser doping method, etc. can be used.

Specifically, when the thermal diffusion method is used, a diffusion layer is formed on both the front and back of the silicon substrate, and then an etching process is performed to etch away the diffusion layer on the back and the phosphorous silica glass or borosilicate glass on the front; When ion implantation or laser doping is used, a diffusion layer is formed only on the front surface of the silicon substrate, and then an etching process is performed to etch away the phosphosilicate glass or borosilicate glass on the front surface.

Optionally, wet etching can be used to perform the etching process, using a mixed acid solution of nitric acid and hydrofluoric acid, or a potassium hydroxide solution, or a sodium hydroxide solution.

Step S102: forming a dielectric layer on the back surface of the silicon substrate.

Referring to FIG. 3, a dielectric layer 3 is formed on the back surface of the silicon substrate 1.

Step S103: forming a polysilicon layer on the lower surface of the dielectric layer.

Referring to FIG. 4, a polysilicon layer 4 is formed on the lower surface of the dielectric layer 3.

Specifically, a plasma enhanced chemical vapor deposition method or a physical vapor deposition method is used to prepare the polysilicon layer, and high temperature annealing is performed in the range of 700°C to 1000°C.

It can be understood that the polysilicon layer is an undoped polysilicon layer.

Step S104: forming a first type doped layer on the lower surface of the polysilicon layer.

Referring to FIG. 5, a first type doped layer 5 is formed on the lower surface of the polysilicon layer 5.

It should be noted that the polarity of the first-type doped layer is not specifically limited in this embodiment, and it can be an N-type doped layer or a P-type doped layer. For example, the first type doping layer may be silicon dioxide doped with dopants, or borosilicate glass, or phosphorous silicate glass, or a liquid dopant source containing dopants, where the dopants may be phosphorous. Or boron.

Step S105: Use a laser heating method to heat the first predetermined region of the first type doped layer, so that the region corresponding to the polysilicon layer and the first predetermined region forms a first doped polysilicon region, to obtain The first polysilicon layer.

It can be understood that the first predetermined area is a partial area of the first type doped layer, not the entire area of the first type doped layer. In the same way, the polarity of the first doped polysilicon region is the same as the polarity of the first type doped layer. Wherein, the first polysilicon layer is composed of a first doped polysilicon region and a polysilicon region.

Referring to FIG. 6, the first predetermined area of the first type doped layer 5 is heated by laser heating, so that the phosphorus or boron dopant in the first type doped layer 5 enters the polysilicon layer 4, so that the polysilicon layer In the region corresponding to the first predetermined region, a first doped polysilicon region is formed, and the first polysilicon layer 6 is obtained.

Step S106: Remove the first type doped layer.

Specifically, when the first type doped layer is silicon dioxide doped with dopants, or borosilicate glass, or phosphosilicate glass, it can be removed with a hydrofluoric acid solution.

Step S107: forming a second-type doped layer on the lower surface of the first polysilicon layer, and the second-type doped layer and the first-type doped layer have opposite polarities.

Referring to FIG. 7, a second type doped layer 7 is formed on the lower surface of the first polysilicon layer 6.

It should be pointed out that the polarity of the second type doped layer is not specifically limited in this embodiment, as long as the polarity of the first type doped layer is opposite to that of the first type doped layer. For example, the first type doping layer may be silicon dioxide doped with dopants, or borosilicate glass, or phosphorous silicate glass, or a liquid dopant source containing dopants, where the dopants may be phosphorous. Or boron.

Step S108: Use a laser heating method to heat the second predetermined area of the second type doped layer, so that the area corresponding to the first polysilicon layer and the second predetermined area forms a second doping The polysilicon region obtains a second polysilicon layer, and the second polysilicon layer has a polysilicon spacer region between the first doped polysilicon region and the second doped polysilicon region.

Referring to FIG. 8, the second predetermined area of the second type doped layer 7 is heated by laser heating, so that the phosphorus or boron dopant in the second type doped layer 7 enters the first polysilicon layer 6 , Forming a second doped polysilicon region in the region corresponding to the second predetermined region in the first polysilicon layer 6 to obtain the second polysilicon layer 8.

It can be understood that the second predetermined area is a partial area of the second type doped layer, and there is a gap between the formed second doped polysilicon area and the first doped polysilicon area, and the gap is the polysilicon spacer. , The polysilicon spacer is undoped polysilicon. Wherein, the second polysilicon layer is composed of a first doped polysilicon region, a second doped polysilicon region, and a polysilicon region.

It can also be understood that, since the polarity of the second type doped layer and the first type doped layer are opposite, the polarity of the second doped polysilicon region and the first doped polysilicon region are also opposite.

Step S109: Remove the second type doped layer.

Specifically, when the second-type doped layer is silicon dioxide doped with dopants, or borosilicate glass, or phosphosilicate glass, it can be removed with a hydrofluoric acid solution.

Step S110: forming a first passivation layer on the lower surface of the second polysilicon layer.

Referring to FIG. 9, a first passivation layer 9 is formed on the lower surface of the second polysilicon layer 8.

Specifically, a plasma chemical vapor deposition method may be used to deposit the first passivation layer.

Step S111: forming an anti-reflection layer on the upper surface of the diffusion layer.

Referring to FIG. 10, an anti-reflection layer 10 is formed on the upper surface of the diffusion layer 2.

Specifically, the anti-reflective layer can be deposited by plasma chemical vapor deposition. Of course, other methods, such as organic chemical vapor deposition, can also be used. The anti-reflective layer has the dual effects of anti-reflective reduction, antireflection, and passivation.

Step S112: forming a metal electrode on the lower surface of the first passivation layer.

Referring to FIG. 11, a metal electrode 11 is formed on the lower surface of the first passivation layer 9.

Specifically, the metal electrode is prepared by a screen printing method, and sintered, so that the metal electrode burns through the first passivation layer and contacts the second polysilicon layer.

On the basis of any of the foregoing embodiments, in an embodiment of the present application, forming a first-type doped layer on the lower surface of the polysilicon layer includes:

The first-type doped layer is formed on the lower surface of the polysilicon layer by any one of atmospheric pressure chemical vapor deposition method, screen printing method, inkjet method, and spin coating method.

On the basis of any of the foregoing embodiments, in an embodiment of the present application, the forming a dielectric layer on the back surface of the silicon substrate includes:

The dielectric layer is formed on the back surface of the silicon substrate by any one of a chemical vapor deposition method, a high temperature thermal oxygen oxidation method, and a nitric acid oxidation method.

In the solar cell manufacturing method of this embodiment, when forming the second polysilicon layer with the polysilicon spacers, the first doped polysilicon region and the second doped polysilicon region with opposite polarities, the second polysilicon layer is formed by laser heating. For the first doped polysilicon region and the second doped polysilicon region, the entire manufacturing process does not require any step of patterning any layer, nor does it require additional high-temperature processing, which simplifies the solar cell manufacturing process, thereby improving the production efficiency of solar cells .

Please refer to FIG. 12, which is a flowchart of another solar cell manufacturing method provided by an embodiment of the application, and the method includes:

Step S201: texturing the silicon substrate.

It should be pointed out that a wet texturing process can be used for texturing the silicon substrate. When the silicon substrate is single crystal silicon, an alkaline solution is used for texturing, such as potassium hydroxide solution. When it is polysilicon, use acidic solution for texturing, such as hydrofluoric acid solution.

In this embodiment, when texturing is used, the surface of the silicon substrate has a textural structure, which produces a light trapping effect and increases the amount of light absorbed by the solar cell, thereby improving the efficiency of the solar cell.

Preferably, the silicon substrate is cleaned before texturing to remove metal and organic contaminants on the surface.

Step S202: forming a diffusion layer on the front surface of the silicon substrate.

Preferably, when an ion implantation method or a laser doping method is used to form a diffusion layer on the front surface of the silicon substrate, during the etching process, the back surface of the silicon substrate is etched flat to increase the current of the solar cell.

Step S203: forming a dielectric layer on the back surface of the silicon substrate.

Step S204: forming a polysilicon layer on the lower surface of the dielectric layer.

Step S205: forming a first type doped layer on the lower surface of the polysilicon layer.

Step S206: Remove the first type doped layer.

Step S207: Use a laser heating method to heat the first predetermined area of the first type doped layer, so that the polysilicon layer and the area corresponding to the first predetermined area form a first doped polysilicon area, and obtain The first polysilicon layer.

Step S208: forming a second-type doped layer on the lower surface of the first polysilicon layer, and the second-type doped layer and the first-type doped layer have opposite polarities.

Step S209: Use laser heating to heat the second predetermined area of the second type doped layer, so that the area corresponding to the first polysilicon layer and the second predetermined area forms a second doping The polysilicon region obtains a second polysilicon layer, and the second polysilicon layer has a polysilicon spacer region between the first doped polysilicon region and the second doped polysilicon region.

Step S210: removing the second type doped layer.

Step S211: forming a first passivation layer on the lower surface of the second polysilicon layer.

Step S212: forming a second passivation layer on the upper surface of the diffusion layer.

Step S213: forming an anti-reflection layer on the upper surface of the second passivation layer.

It should be noted that the method for forming the second passivation layer is not specifically limited in this embodiment, and it depends on the situation. For example, a plasma chemical vapor deposition method or an organic chemical vapor deposition method can be used.

In this embodiment, the purpose of forming the second passivation layer is to form a laminated film with a passivation effect with the anti-reflection layer to improve the photoelectric conversion efficiency of the solar cell.

Step S214: forming a metal electrode on the lower surface of the first passivation layer.

It should be pointed out that this application does not specifically limit the sequence of steps for preparing solar cells, and can be adjusted according to the actual production process.

The present application also provides a solar cell. Please refer to FIG. 13. FIG. 13 is a schematic structural diagram of a solar cell provided by an embodiment of the application. The solar cell includes:

Silicon substrate 1;

The dielectric layer 3 on the back of the silicon substrate 1;

The second polysilicon layer 8 is located on the lower surface of the dielectric layer 3, and the second polysilicon layer 8 includes a first doped polysilicon region, a second doped polysilicon region, and is located on the first doped polysilicon region. A polysilicon spacer between a region and the second doped polysilicon region, wherein the first doped polysilicon region and the second doped polysilicon region have opposite polarities, and the first doped polysilicon region And the second doped polysilicon region are both obtained by laser heating;

The first passivation layer 9 located on the lower surface of the second polysilicon layer 8;

The metal electrode 11 located on the lower surface of the first passivation layer 9;

The diffusion layer 2 located on the front side of the silicon substrate 1;

The anti-reflection layer 10 located on the upper surface of the diffusion layer 2.

Optionally, in an embodiment of the present application, the silicon substrate 1 is an N-type silicon substrate, but the present application does not specifically limit this. In other embodiments of the present application, the silicon substrate 1 is P Type silicon substrate. The thickness of the silicon substrate 1 is between 100 μm and 250 μm. When the silicon substrate 1 is a textured substrate, the etching thickness of the front and back sides of the silicon substrate 1 is between 5 μm and 20 μm.

In an embodiment of the present application, the diffusion layer 2 is an N-type diffusion layer 2, but this application does not specifically limit this. In other embodiments of the present application, the diffusion layer 2 may also be a P-type diffusion layer 2.

It should be pointed out that in this embodiment, the type of the dielectric layer 3 is not specifically limited, and it depends on the situation. For example, the dielectric layer 3 is any one of the following: a silicon dioxide dielectric layer 3, a silicon nitride dielectric layer 3, an aluminum oxide dielectric layer 3, and a hafnium oxide dielectric layer 3.

It should be noted that in this embodiment, the polarities of the first doped polysilicon region and the second doped polysilicon region are not specifically limited, as long as the polarities of the two are opposite. For example, when the first doped polysilicon area is an N-type doped area, the second doped polysilicon area is a P-type doped area; when the first doped polysilicon area is a P-type doped area, the second doped polysilicon area is a P-type doped area. The region is an N-type doped region.

In an embodiment of the present application, the first passivation layer 9 is a silicon nitride layer, but this application does not specifically limit this. In other embodiments of the present application, the first passivation layer 9 may also be a silicon nitride layer. A stack of silicon dioxide and silicon nitride layers. Among them, the thickness of the silicon nitride layer ranges from 40 nanometers to 150 nanometers, including the endpoint values, to produce a good passivation effect on the silicon substrate 1; the thickness of the silicon dioxide layer ranges from 1 nanometers to 25 nanometers, including The endpoint value is used to produce a good passivation effect on the silicon substrate 1.

The purpose of the anti-reflection layer 10 is to reduce the reflection of light and increase the amount of light absorbed by the solar cell. On the other hand, it can also have a passivation effect, thereby improving the efficiency of the solar cell. Specifically, the anti-reflection layer 10 is a silicon nitride layer.

Optionally, the thickness of the anti-reflective layer 10 ranges from 40 nanometers to 150 nanometers, including the endpoint value, so as to produce a good passivation effect and anti-reflective effect.

The first doped polycrystalline silicon region and the second doped polycrystalline silicon region with opposite polarities in the second polycrystalline silicon layer 8 in the solar cell in this embodiment are both obtained by laser heating, and no patterning step is required. There is also no need for an additional high-temperature treatment process, which makes the manufacturing process of the solar cell easier, thereby improving the production efficiency of the solar cell.

Preferably, in an embodiment of the present application, the thickness of the dielectric layer 3 ranges from 1 nanometer to 4 nanometers, inclusive. The dielectric layer 3 not only has a passivation effect on the surface of the silicon substrate 1, but also needs to allow carriers to tunnel through. When the thickness of the dielectric layer 3 is less than 1 nanometer, it cannot play a passivation effect; and when the thickness of the dielectric layer 3 When the thickness is greater than 4 nanometers, carriers cannot tunnel effectively.

Preferably, in an embodiment of the present application, the thickness of the second polysilicon layer 8 ranges from 50 nanometers to 300 nanometers, inclusive. If the thickness of the second polysilicon layer 8 is too small, the The stack composed of the second polysilicon layer 8 and the dielectric layer 3 has a poor passivation effect on the surface of the silicon substrate 1, and the metal electrode 11 paste easily burns through the second polysilicon layer 8 to contact the silicon substrate 1; If the thickness of the second polysilicon layer 8 is too large, a relatively large recombination loss will occur when the carriers are transported in the second polysilicon layer 8, resulting in a decrease in the performance of the solar cell.

On the basis of any of the foregoing embodiments, in an embodiment of the present application, please refer to FIG. 14. The solar cell further includes:

The second passivation layer 12 is located between the diffusion layer 2 and the anti-reflection layer 10.

The purpose of the second passivation layer 12 is to form a stack with the anti-reflection layer 10 to have a passivation effect, so as to improve the efficiency of the solar cell. Specifically, the second passivation layer 12 may be a silicon dioxide layer.

Optionally, the thickness of the second passivation layer 12 ranges from 1 nanometer to 25 nanometers, including the endpoint value, so as to produce a good passivation effect on the silicon substrate 1.

The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

The solar cell and its manufacturing method provided by this application are described in detail above. Specific examples are used in this article to illustrate the principles and implementation of the application, and the description of the above examples is only used to help understand the method and core ideas of the application. It should be pointed out that for those of ordinary skill in the art, without departing from the principles of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims (10)

A method for manufacturing solar cells, which is characterized in that it comprises: Form a diffusion layer on the front side of the silicon substrate; Forming a dielectric layer on the back surface of the silicon substrate; Forming a polysilicon layer on the lower surface of the dielectric layer; Forming a first type doped layer on the lower surface of the polysilicon layer; The first predetermined area of the first type doped layer is heated by laser heating, so that the area corresponding to the first predetermined area of the polysilicon layer forms a first doped polysilicon area, and a first polysilicon area is obtained. Crystalline silicon layer; Removing the first type doped layer; Forming a second-type doped layer on the lower surface of the first polysilicon layer, and the second-type doped layer and the first-type doped layer have opposite polarities; Laser heating is used to heat the second predetermined area of the second type doped layer, so that the area corresponding to the first polysilicon layer and the second predetermined area forms a second doped polysilicon area, Obtaining a second polysilicon layer, and the second polysilicon layer has a polysilicon spacer between the first doped polysilicon region and the second doped polysilicon region; Removing the second type doped layer; Forming a first passivation layer on the lower surface of the second polysilicon layer; Forming an anti-reflection layer on the upper surface of the diffusion layer; A metal electrode is formed on the lower surface of the first passivation layer. The method for manufacturing a solar cell according to claim 1, wherein forming a first type doped layer on the lower surface of the polysilicon layer comprises: The first-type doped layer is formed on the lower surface of the polysilicon layer by any one of atmospheric pressure chemical vapor deposition method, screen printing method, inkjet method, and spin coating method. The method for manufacturing a solar cell according to claim 1, wherein forming a diffusion layer on the front surface of the silicon substrate comprises: Using thermal diffusion or ion implantation, the diffusion layer is formed on the front surface of the silicon substrate. The method of manufacturing a solar cell according to claim 1, wherein said forming a dielectric layer on the back of said silicon substrate comprises: The dielectric layer is formed on the back surface of the silicon substrate by any one of a chemical vapor deposition method, a high temperature thermal oxygen oxidation method, and a nitric acid oxidation method. The method for manufacturing a solar cell according to claim 1, wherein before the polysilicon layer is formed on the back surface of the silicon substrate, the method further comprises: Texturing the silicon substrate. The method for manufacturing a solar cell according to any one of claims 1 to 5, characterized in that, before the anti-reflection layer is formed on the upper surface of the diffusion layer, the method further comprises: Forming a second passivation layer on the upper surface of the diffusion layer; Correspondingly, forming an anti-reflective layer on the upper surface of the diffusion layer includes: forming the anti-reflective layer on the upper surface of the second passivation layer. A solar cell, characterized in that it comprises: Silicon substrate A dielectric layer on the back of the silicon substrate; The second polysilicon layer is located on the lower surface of the dielectric layer, and the second polysilicon layer includes a first doped polysilicon region, a second doped polysilicon region, and is located on the first doped polysilicon region. The polysilicon spacers between the second doped polysilicon regions, wherein the first doped polysilicon regions and the second doped polysilicon regions have opposite polarities, and the first doped polysilicon regions and the The second doped polysilicon regions are all obtained by laser heating; A first passivation layer located on the lower surface of the second polysilicon layer; A metal electrode located on the lower surface of the first passivation layer; A diffusion layer located on the front side of the silicon substrate; An anti-reflection layer located on the upper surface of the diffusion layer. 8. The solar cell of claim 7, wherein the dielectric layer is any one of the following: Silicon dioxide dielectric layer, silicon nitride dielectric layer, aluminum oxide dielectric layer, hafnium oxide dielectric layer. 8. The solar cell of claim 8, wherein the thickness of the dielectric layer ranges from 1 nanometer to 4 nanometers, inclusive. The solar cell according to any one of claims 7 to 9, characterized in that it further comprises: A second passivation layer located between the diffusion layer and the anti-reflection layer.

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