CN116137299A

CN116137299A - Solar cell and preparation method thereof

Info

Publication number: CN116137299A
Application number: CN202310092732.7A
Authority: CN
Inventors: 石鑫鑫; 黄智�
Original assignee: Tongwei Solar Meishan Co Ltd
Current assignee: Tongwei Solar Meishan Co Ltd
Priority date: 2023-01-31
Filing date: 2023-01-31
Publication date: 2023-05-19
Anticipated expiration: 2043-01-31
Also published as: CN116137299B; WO2024160191A1

Abstract

The invention discloses a solar cell and a preparation method thereof, which belong to the technical field of solar cells, wherein the solar cell comprises: a silicon substrate; the anti-reflection film is attached to the silicon substrate and comprises at least one layer of film body, wherein at least one layer of film body in the anti-reflection film is a phosphorus-doped anti-reflection film; an electrode penetrating the anti-reflection film and forming ohmic contact with the silicon substrate, wherein the contact part of the electrode and the silicon substrate forms a silver-silicon alloy containing phosphorus; by doping phosphorus into the anti-reflection film, the addition of the phosphorus does not affect the refractive index and the reflectivity of the anti-reflection film, after the electrode paste is printed on the grid line area, the electrode paste can puncture the anti-reflection film in the sintering process, and at the moment, the phosphorus in the anti-reflection film is sintered into the silver-silicon alloy, so that the phosphorus concentration in the silicon matrix is improved, the ohmic contact of the silver-silicon alloy is improved, and the contact resistance is reduced.

Description

Solar cell and preparation method thereof

Technical Field

The invention relates to the technical field of solar cells, in particular to a solar cell and a preparation method thereof.

Background

The production flow of the PERC battery in the current mainstream is as follows: texturing, diffusion, laser SE doping, alkali polishing, annealing, back film, positive film and screen printing, wherein phosphorus doping is carried out in the diffusion process to form PN junction; further phosphorus doping in the laser SE procedure forms high-concentration doping in the grid line area, but low-concentration doping in the grid line area. Therefore, good ohmic contact between silver paste and silicon substrate can be ensured when the front side auxiliary grid is printed by screen printing, and excessive phosphorus atom concentration on the surface of the undoped region can be avoided, so that open voltage loss caused by serious surface recombination is avoided. Under the trend of reducing cost and enhancing efficiency, in order to reduce the unit consumption of positive silver, the printing width and the printing height of the front auxiliary grid are continuously reduced, the contact area of silver paste and a silicon substrate is continuously reduced, so that the electric shock resistance is overlarge, and the conversion efficiency is seriously reduced.

The conventional contact resistance reduction method mainly starts from diffusion and laser SE doping, mainly comprises the steps of adjusting a diffusion process structure, increasing the thickness of phosphosilicate glass (PSG) formed in the diffusion process or the phosphorus concentration in a PSG layer, and then pushing phosphorus in the PSG into silicon by laser to realize selective high-concentration phosphorus doping, namely SE doping. The mode is greatly limited by a diffusion structure, and as the diffusion is to carry out phosphorus doping on the surface of the whole silicon wafer without difference, the phosphorus concentration of the PSG layer is increased, and the phosphorus concentration of other non-grid line areas is also increased, so that the surface concentration is too high, the recombination is aggravated, the contact is improved to a certain extent, the open pressure is reduced, and the overall efficiency is not obviously improved. The phosphorus doping concentration of the grid line region can be improved to a certain extent by increasing the laser energy, but the laser damage is increased, and the open voltage is also seriously and negatively influenced, so that the battery efficiency is not improved.

Disclosure of Invention

The purpose of the application is to provide a solar cell and a preparation method thereof, so as to solve the problem of overlarge contact resistance between silver and silicon at present.

In a first aspect, embodiments of the present application provide a solar cell, the solar cell including:

a silicon substrate;

The antireflection film is attached to the silicon substrate and comprises at least one layer of film body, wherein at least one layer of film body in the antireflection film is a phosphorus-doped antireflection film; and

and the electrode penetrates through the anti-reflection film to form ohmic contact with the silicon substrate, and the contact part of the electrode and the silicon substrate forms phosphorus-containing silver-silicon alloy.

By doping phosphorus into the anti-reflection film, the addition of the phosphorus does not affect the refractive index and the reflectivity of the anti-reflection film, after electrode slurry is printed in a grid line area, the electrode slurry can puncture the anti-reflection film in the sintering process, and at the moment, the phosphorus in the anti-reflection film is sintered into silver-silicon alloy, so that the phosphorus concentration in a silicon substrate is improved, the ohmic contact of the silver-silicon alloy is improved, and the contact resistance is reduced.

With reference to the first aspect, in an alternative embodiment of the present application, the phosphorus-doped anti-reflection film includes a phosphorus-doped silicon nitride anti-reflection film, a phosphorus-doped silicon oxynitride anti-reflection film, or a phosphorus-doped silicon oxide anti-reflection film.

The anti-reflection film can be selected from a silicon nitride anti-reflection film, a silicon oxynitride anti-reflection film, a silicon oxide anti-reflection film and the like, and phosphorus can be doped into each anti-reflection film at will to improve the phosphorus concentration in a silicon substrate, improve the ohmic contact of silver-silicon alloy and further reduce the contact resistance.

With reference to the first aspect, in an alternative embodiment of the present application, the volume content of phosphorus in the phosphorus-doped anti-reflection film is 0.5% -5%;

preferably, the volume content of the phosphorus in the phosphorus-doped anti-reflection film is 1.5-4%;

more preferably, the volume content of the phosphorus in the phosphorus-doped anti-reflection film is 2.5% -3%.

The doped content of the phosphorus in the anti-reflection film determines the amount of the phosphorus which can be sintered into the silver-silicon alloy to a certain extent, and the higher the doped content of the phosphorus in the anti-reflection film is, the more the doped content of the phosphorus is sintered into the silver-silicon alloy, so that the contact is improved, and the person skilled in the art can select the volume content of the phosphorus in the phosphorus-doped anti-reflection film according to actual needs, for example, the volume content of the phosphorus in the phosphorus-doped anti-reflection film is 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% and the like.

With reference to the first aspect, in an optional embodiment of the present application, at least one layer of film body in the anti-reflection film is a silicon nitride anti-reflection film; and/or

At least one layer of film body in the anti-reflection film is a silicon oxynitride anti-reflection film; and/or

At least one layer of film body in the antireflection film is a silicon oxide antireflection film.

In the implementation process, the number of layers and the types of the layers of the antireflection film can be selected by a person skilled in the art according to actual needs.

With reference to the first aspect, in an optional embodiment of the present application, a refractive index of each of the film bodies in the anti-reflection film is different.

With reference to the first aspect, in an alternative embodiment of the present application, the refractive index of the film body gradually decreases in the direction from inside to outside.

The high refractive index of the film layer close to the silicon is controlled because the high H content in the silicon nitride with high refractive index can form better hydrogen passivation on the silicon wafer, and the low refractive index of the surface layer is controlled to form better anti-reflection effect.

With reference to the first aspect, in an optional embodiment of the present application, the anti-reflection film includes a first phosphorus-doped silicon nitride anti-reflection film, a second phosphorus-doped silicon nitride anti-reflection film, a third phosphorus-doped silicon nitride anti-reflection film, a fourth phosphorus-doped silicon nitride anti-reflection film, a silicon oxynitride anti-reflection film, and a silicon oxide anti-reflection film stacked layer by layer along a direction from inside to outside.

In a second aspect, an embodiment of the present application further provides a method for preparing a solar cell, where the method includes:

obtaining a silicon substrate to be treated;

depositing an antireflection film on a silicon substrate, wherein the antireflection film comprises at least one film body, and at least one film body in the antireflection film is a phosphorus-doped antireflection film;

and preparing an electrode on the silicon substrate subjected to the deposition of the anti-reflection film, and sintering the electrode to enable the electrode to penetrate through the anti-reflection film to form ohmic contact with the silicon substrate, and enabling phosphorus in the anti-reflection film to be sintered into a part of the electrode penetrating through the anti-reflection film to form silver-silicon alloy containing phosphorus, so that the solar cell is obtained.

The method skips the conventional means for improving the silver-silicon ohmic contact, avoids starting from diffusion or laser SE doping, and selects to perform phosphorus doping from the positive film. The method is characterized in that the plasma chemical vapor deposition (PECVD) PERC battery is used for positively reducing reflection of a laminated silicon nitride film and simultaneously introducing phosphorus-containing gas, so that new working procedures are not added, the optical performance of the positively reducing reflection film is not influenced, and the passivation performance of the positively-arranged film is not negatively influenced.

With reference to the second aspect, in an alternative embodiment of the present application, the phosphorus-doped anti-reflection film includes a phosphorus-doped silicon nitride anti-reflection film, a phosphorus-doped silicon oxynitride anti-reflection film, or a phosphorus-doped silicon oxide anti-reflection film.

With reference to the second aspect, in an alternative embodiment of the present application, the method for preparing the phosphorus-doped anti-reflection film includes:

and mixing a phosphorus-containing gas into the deposition atmosphere, and then performing deposition to obtain the phosphorus-doped anti-reflection film.

With reference to the second aspect, in an alternative embodiment of the present application, the phosphorus-containing gas includes at least one of phosphane, phosphorus trifluoride, and phosphorus pentafluoride.

Due to Phosphane (PH) ₃ ) Phosphorus trifluoride (PF) ₃ ) Phosphorus Pentafluoride (PF) ₅ ) The phosphorus-doped gas can not react with deposition atmospheres such as silane, ammonia and the like to generate other products at the positive film deposition temperature of 500-600 ℃, and the phosphane can decompose to generate phosphorus and hydrogen at about 500 ℃, so that the phosphorus-doped gas is directly doped in the anti-reflection film layer in a phosphorus simple substance form.

With reference to the second aspect, in an alternative embodiment of the present application, the flow rate of the phosphorus-containing gas is 2000-8000sccm.

The control of the phosphorus content in the anti-reflection film can be controlled by controlling the flow of the phosphorus-containing gas, and the higher the phosphane flow is, the more contact is improved, and particularly the phosphane flow of the bottom layer is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart of a method provided by an embodiment of the present application;

fig. 2 is a graph showing the results of the front reflectivity test of the battery sheets provided in example 3 and comparative example 1;

fig. 3 is a schematic structural diagram of a solar cell according to an embodiment of the present application.

Reference numerals: 1-silicon matrix, 2-electrode, 3-n+ emitter, 4-antireflection film, 5-phosphorus-containing silver-silicon alloy.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

Applicants found during the course of the invention that: in order to enable the front silver auxiliary grid of the PERC battery to form good ohmic contact with the silicon substrate, a common method in industrial production is to print silver paste on the front surface and sinter at high temperature, and carriers generated by PN junctions in the silicon substrate after metallization can be well collected by the front auxiliary grid, then transmitted to the front main grid and then converged to a welding point (PAD point) for export. Among the factors that influence the formation of silver-silicon alloy ohmic contacts are mainly: (1) the PSG layer formed on the surface of the diffused silicon wafer is used as a doped phosphorus source for laser SE doping in the next process, so that the thicker the PSG layer is, the higher the phosphorus concentration of a heavily doped region formed after SE doping is, and the more ohmic contact of silver-silicon alloy is facilitated; (2) the process parameters of the laser SE, such as laser power, energy and the like, also influence the phosphorus concentration of the heavily doped region; (3) glass body content in silver paste, after screen printing silver paste, glass body in silver paste can pierce the antireflection film on the surface of the silicon wafer in the sintering process so as to be in contact with the silicon substrate. For diffusion, the common means is to adjust the diffusion process structure, and the optimization of the diffusion process can reduce the contact resistance of silver and silicon to a certain extent and improve ohmic contact, but inevitably has negative influence on a light diffusion region and has small lifting amplitude; for laser SE, the common means is to increase the laser power or energy, the optimal laser process parameters are basically matched on the production line at present, the optimization space is extremely small, for example, in other schemes, a second diffusion step is added after laser heavy doping, so that new working procedures are increased, and the industrial production and use are not facilitated; for optimization of slurry, too high glass content can cause excessive damage to the anti-reflection film, surface minority carrier recombination rises sharply, and loss of opening pressure is brought.

The conventional diffusion+SE technical route is the most common PERC battery production technical route in industrial production at present, although compared with the past aluminum back surface field battery (Al-BSF), the SE doped light doped region and the SE doped region can be selectively formed, and the conversion efficiency of the solar battery is greatly improved. However, with the continuous development of PERC battery technology in recent 10 years, the demands for cost reduction and efficiency improvement are larger and larger, the conventional process parameter optimization is difficult to bring about rapid improvement in efficiency, and with the narrower and narrower width of grid line printing, the requirements on silver-silicon alloy contact are higher and higher, and the limitation on silver-silicon alloy ohmic contact is difficult to open only through diffusion, SE or slurry optimization, so that the graphic design, process optimization and cost reduction and efficiency improvement are extremely limited, and the efficiency improvement is difficult.

The application intends to skip the conventional means for improving the silver-silicon ohmic contact, avoid starting from diffusion or laser SE doping, and select to start from improving the direction of the antireflection film so as to solve the problem of overlarge contact resistance between silver and silicon at present.

Referring to fig. 3, a solar cell according to an embodiment of the present application includes: silicon substrate, antireflection film and electrode.

Regarding the antireflection film, the antireflection film is attached to the silicon substrate, the antireflection film includes at least one film body, at least one film body in the antireflection film is a phosphorus-doped antireflection film, and it should be noted that the antireflection film may be directly attached to the silicon substrate or indirectly attached to the silicon substrate, for example, the antireflection film may be formed by n ⁺ The emitter is indirectly attached to the silicon substrate, wherein n ⁺ The emitter is formed during diffusion of the silicon substrate, in effect a phosphorus doped silicon layer.

By doping phosphorus into the anti-reflection film, the addition of the phosphorus does not affect the refractive index and the reflectivity of the anti-reflection film, after electrode slurry is printed in a grid line area, the electrode slurry can puncture the anti-reflection film in the sintering process, and at the moment, the phosphorus in the anti-reflection film is sintered into silver-silicon alloy, so that the phosphorus concentration in a silicon substrate is improved, the ohmic contact of the silver-silicon alloy is improved, and the contact resistance is reduced. The electrode paste may be specifically selected from silver.

In some embodiments, the phosphorus-doped anti-reflective film comprises a phosphorus-doped silicon nitride anti-reflective film, a phosphorus-doped silicon oxynitride anti-reflective film, or a phosphorus-doped silicon oxide anti-reflective film.

When the film body of the antireflection film has only one layer, the film body is a phosphorus-doped silicon nitride antireflection film, a phosphorus-doped silicon oxynitride antireflection film or a phosphorus-doped silicon oxide antireflection film.

In some embodiments, at least one of the film bodies in the anti-reflective film is a silicon nitride anti-reflective film.

When the film body of the antireflection film is two layers, one layer of film body is a silicon nitride antireflection film, and the other layer of film body is a phosphorus-doped silicon nitride antireflection film, a phosphorus-doped silicon oxynitride antireflection film or a phosphorus-doped silicon oxide antireflection film. When the film body of the antireflection film is three layers or more, at least one layer of film body is a silicon nitride antireflection film, and the rest film body is at least one of a phosphorus-doped silicon nitride antireflection film, a phosphorus-doped silicon oxynitride antireflection film and a phosphorus-doped silicon oxide antireflection film.

In some embodiments, at least one of the film bodies in the anti-reflective film is a silicon oxynitride anti-reflective film.

When the film body of the antireflection film is two layers, one layer of film body is a silicon oxynitride antireflection film, and the other layer of film body is a phosphorus-doped silicon nitride antireflection film, a phosphorus-doped silicon oxynitride antireflection film or a phosphorus-doped silicon oxide antireflection film. When the film body of the antireflection film is three layers or more, at least one layer of the film body is a silicon oxynitride antireflection film, and the rest of the film body is at least one of a phosphorus-doped silicon nitride antireflection film, a phosphorus-doped silicon oxynitride antireflection film and a phosphorus-doped silicon oxide antireflection film, which are only some examples and are not exhaustive, but those skilled in the art can know that other embodiments are also included.

In some embodiments, at least one of the film bodies in the anti-reflective film is a silicon oxide anti-reflective film.

When the film body of the antireflection film is two layers, one layer of film body is a silicon oxide antireflection film, and the other layer of film body is a phosphorus-doped silicon nitride antireflection film, a phosphorus-doped silicon oxynitride antireflection film or a phosphorus-doped silicon oxide antireflection film. When the film body of the antireflection film is three layers or more, at least one layer of the film body is a silicon oxide antireflection film, and the rest of the film body is at least one of a phosphorus-doped silicon nitride antireflection film, a phosphorus-doped silicon oxynitride antireflection film and a phosphorus-doped silicon oxide antireflection film, which are only some examples and are not exhaustive, but those skilled in the art can know that other embodiments are also included.

In some embodiments, at least one of the film bodies in the anti-reflective film is a silicon nitride anti-reflective film; at least one layer of film body in the antireflection film is a silicon oxynitride antireflection film; at least one layer of film body in the antireflection film is a silicon oxide antireflection film.

When the film body of the antireflection film is three layers, one layer of the film body is a phosphorus-doped silicon nitride antireflection film, a phosphorus-doped silicon oxynitride antireflection film or a phosphorus-doped silicon oxide antireflection film, and the remaining two layers comprise at least one of the silicon nitride antireflection film, the silicon oxynitride antireflection film and the silicon oxide antireflection film. When the film body of the antireflection film is four or more layers, at least two of the layers include at least one of a phosphorus-doped silicon nitride antireflection film, a phosphorus-doped silicon oxynitride antireflection film and a phosphorus-doped silicon oxide antireflection film, and the remaining film body includes at least one of a silicon nitride antireflection film, a silicon oxynitride antireflection film and a silicon oxide antireflection film, the above are only examples, and the above are not exhaustive, but those skilled in the art can know that other embodiments are also included.

In some embodiments, the phosphorus-doped anti-reflection film has a phosphorus content of 0.5% to 5% by volume; preferably, the volume content of the phosphorus in the phosphorus-doped anti-reflection film is 1.5-4%; more preferably, the volume content of the phosphorus in the phosphorus-doped anti-reflection film is 2.5% -3%.

In some embodiments, the refractive index of each film body in the anti-reflective film is different; further, the refractive index of the film body gradually decreases in the direction from inside to outside, and it should be noted that, in the present application, the inside refers to the direction approaching the silicon substrate, and the outside refers to the direction separating from the silicon substrate. The high refractive index of the film layer close to the silicon is controlled because the high H content in the silicon nitride with high refractive index can form better hydrogen passivation on the silicon wafer, and the low refractive index of the surface layer is controlled to form better anti-reflection effect.

In this embodiment, the antireflection film includes, in the direction from the inside to the outside, a first phosphorus-doped silicon nitride antireflection film, a second phosphorus-doped silicon nitride antireflection film, a third phosphorus-doped silicon nitride antireflection film, a fourth phosphorus-doped silicon nitride antireflection film, a silicon oxynitride antireflection film, and a silicon oxide antireflection film stacked layer by layer.

With respect to the electrode, the electrode penetrates through the anti-reflection film to form ohmic contact with the silicon substrate, and a phosphorus-containing silver-silicon alloy is formed at a contact part of the electrode and the silicon substrate. The material of the electrode may be selected from silver. In this embodiment, the electrode is n on the silicon substrate ⁺ The emitter forms an ohmic contact.

Referring to fig. 1, an embodiment of the present application further provides a method for manufacturing a solar cell, where the method includes:

s1, acquiring a silicon substrate to be treated;

s2, depositing an antireflection film on a silicon substrate, wherein the antireflection film comprises at least one layer of film body, and at least one layer of film body in the antireflection film is a phosphorus-doped antireflection film;

and S3, preparing an electrode on the silicon substrate subjected to the deposition of the anti-reflection film, and sintering the electrode so that the electrode penetrates through the anti-reflection film to form ohmic contact with the silicon substrate, and the phosphorus in the anti-reflection film is sintered into the part of the electrode penetrating through the anti-reflection film to form a silver-silicon alloy containing phosphorus, so that the solar cell is obtained.

In some embodiments, the method of preparing the phosphorus-doped anti-reflection film includes: and mixing a phosphorus-containing gas into the deposition atmosphere, and then performing deposition to obtain the phosphorus-doped anti-reflection film.

Introducing phosphorus-doped gas, e.g. Phosphane (PH), directly into the deposition atmosphere during the deposition of the positive film ₃ ) Phosphorus trifluoride (PF) ₃ ) Phosphorus Pentafluoride (PF) ₅ ) And the like, because the phosphorus-doped gases can not react with deposition atmospheres such as silane, ammonia and the like to generate other products at the deposition temperature of the positive film of 500-600 ℃, the positive film mainly consists of a silicon nitride film layer, and the phosphane can decompose to generate phosphorus and hydrogen at about 500 ℃, so that the phosphorus-doped gases are directly doped in the anti-reflection film layer in a phosphorus simple substance form.

After the phosphorus is doped in the anti-reflection film, a large amount of phosphorus atoms are contained in the positive anti-reflection film layer, and the phosphorus in the film layer can not diffuse to the surface of the silicon substrate because the diffusion temperature of the phosphorus into the silicon substrate is 820-860 ℃, and the deposition temperature (500-600 ℃) and the screen sintering temperature (600-780 ℃) are lower than the diffusion temperature of the phosphorus, so that the negative effect on a non-grid line area can not be caused. After the electrode paste is printed on the grid line area, the electrode paste can pierce the positive film layer in the sintering process, and phosphorus in the film layer is sintered into silver-silicon alloy, so that the phosphorus concentration in the silicon matrix is increased, and the contact resistance is reduced.

The following is an example of a silicon nitride film as an antireflection film: testing positive film thickness and refractive index with laser ellipsometer, and phosphorus doped silicon nitride film (SiN) _x P) and undoped silicon nitride film (SiN) _x ) The refractive index has no obvious difference; the short wave and long wave responses of the battery piece are tested by adopting a reflectivity meter, and the optical performance of the battery piece is not affected after phosphorus doping; the contact resistance is tested, and the contact resistance of the positive film doped with phosphorus is obviously lower. Other types of anti-reflective films have similar effects after being doped with phosphorus and are not described in detail herein.

In some embodiments, the phosphorus-containing gas includes at least one of phosphane, phosphorus trifluoride, and phosphorus pentafluoride. The flow rate of the phosphorus-containing gas is 2000-8000sccm.

The higher the phosphane flow rate is, the more contact is improved, particularly the phosphane flow rate of the bottom layer is improved, but the higher the flow rate is, the too much doped phosphorus can possibly cause too many impurity atoms near the surface of silicon, so that the surface recombination is aggravated, the opening pressure is low, and meanwhile, the economic benefit is inevitably reduced due to the excessive phosphane in consideration of the economic factors; when the phosphane flow rate is lower than a certain value, although there is a certain improvement, the effect of improving the contact resistance is not great.

The following describes a preparation method by taking a specific antireflection film structure as an example, the antireflection film structure includes: the antireflection film comprises a first phosphorus-doped silicon nitride antireflection film, a second phosphorus-doped silicon nitride antireflection film, a third phosphorus-doped silicon nitride antireflection film, a fourth phosphorus-doped silicon nitride antireflection film, a silicon oxynitride antireflection film and a silicon oxide antireflection film which are stacked layer by layer along the direction from inside to outside. The preparation process is as follows: and adopting plasma chemical vapor deposition (PECVD) equipment, keeping the deposition temperature at 500-600 ℃, and sequentially depositing phosphorus-doped silicon nitride film layers with different thicknesses and refractive indexes under vacuum conditions to finally form the anti-reflection laminated film. The refractive index and thickness of the silicon nitride film layer are controlled by the ratio of the flow rate of the introduced gas, the time, the gas pressure, the power and the duty ratio. Wherein the refractive index of the first phosphorus-doped silicon nitride anti-reflection film close to the surface of the silicon substrate is 2.2-2.3, the thickness is 10-25 nm, the silane flow is 1000-3000 sccm, the ammonia flow is 4000-10000 sccm, the phosphine flow is 2000-8000sccm, the deposition time is 100-200 s, the pressure is 100-250 Pa, and the power is 9000-15000W. Then the refractive index of the second phosphorus-doped silicon nitride anti-reflection film is 2.09-2.17, the thickness is 10-20 nm, the silane flow rate is 800-2000 sccm, the ammonia flow rate is 4000-12000 sccm, the phosphane flow rate is 2000-8000sccm, the deposition time is 50-150 s, the pressure is 100-250 Pa, and the power is 9000-15000W. And then depositing a third phosphorus-doped silicon nitride anti-reflection film with the refractive index of 2.03-2.06, the thickness of 10-20 nm, the silane flow rate of 800-2000 sccm, the ammonia flow rate of 6000-12000 sccm, the phosphane flow rate of 2000-8000sccm, the deposition time of 100-250 s, the pressure of 100-250 Pa and the power of 9000-15000W. The refractive index of the deposited fourth phosphorus-doped silicon nitride anti-reflection film is 1.99-2.03, the thickness is 25-35 nm, the silane flow is 600-1000 sccm, the ammonia flow is 6000-12000 sccm, the phosphane flow is 2000-8000sccm, the deposition time is 100-300 s, the pressure is 100-250 Pa, and the power is 9000-15000W. Depositing a layer of silicon oxynitride anti-reflection film with the refractive index of 1.55-1.90 at 10-25 nm; and finally, depositing a silicon oxide antireflection film on the surface layer, wherein the thickness of the silicon oxide antireflection film is 10-25 nm.

In other embodiments, since the phosphine is directly introduced during the deposition process without affecting the performance of the film, the doping of phosphorus is selective, each film can be selected for doping, and partial film doping can be performed, and the doping concentration is controlled by the flow of the phosphine. Similarly, the structure of the anti-reflection film can be adjusted according to actual production because the phosphorus-containing gas does not affect the film layer structure, for example, the anti-reflection film can be a single silicon nitride film, a multi-layer silicon nitride composite film, a silicon nitride-silicon oxynitride film composite film, a silicon nitride-silicon oxide composite film and the like. The doping of phosphorus is also optional, and the silicon nitride film, the silicon oxynitride film, and the silicon oxide can be doped.

The features and capabilities of the present invention are described in further detail below in connection with the examples.

Example 1

The solar cell comprises a silicon substrate and an antireflection film attached to the silicon substrate, wherein the antireflection film in the embodiment comprises a first phosphorus-doped silicon nitride antireflection film, a second silicon nitride antireflection film, a third silicon nitride antireflection film, a fourth silicon nitride antireflection film, a silicon oxynitride antireflection film and a silicon oxide antireflection film which are stacked layer by layer.

The preparation method comprises the following steps:

s1, wool making: and (3) adopting a monocrystalline P-type silicon wafer, and texturing the front surface and the back surface by alkali to form a suede pyramid light trapping structure.

S2, diffusion: pre-energizing the textured silicon wafer at 780 ℃ and POCl ₃ The flow is 1000sccm, the time is 5min, the oxygen flow is 900sccm, then the temperature is raised to 850 ℃, the temperature raising time is 10min, phosphorus diffuses into the silicon chip at high temperature, then the temperature is lowered to 780 ℃, the source is turned on again, and POCl is carried out ₃ The flow rate is 1300sccm, the time is 13min, the oxygen flow rate is 800sccm, and the pipe is discharged after cooling, so that diffusion is completed. The diffusion sheet resistance center value is 170 Ω/sq.

S3, laser SE: and (3) carrying out laser doping on the front surface of the diffused silicon wafer and the corresponding metalized area of the positive electrode grid line by utilizing the phosphorus-rich PSG layer formed in the diffusion process to form a heavily doped area, so that a selective emitter structure is realized on the front surface of the silicon wafer, a laser spot is 100 mu m, the laser power is 30W, and the square resistance of the heavily doped area is 90 omega/sq.

S4, hot oxygen: and (3) introducing oxygen into the silicon wafer after laser SE for oxidation, forming an oxide layer on the front surface, and protecting the front PN junction from being damaged.

S5, PSG removal: and removing PSG generated on the back and the periphery of the thermally oxidized silicon wafer by using hydrofluoric acid.

S6, alkali polishing: and polishing the back surface and the edge of the silicon wafer after PSG removal, and removing PSG from the front surface.

S7, oxidation annealing: and oxidizing and annealing the silicon wafer subjected to alkali polishing to form a silicon oxide layer on the surface of the silicon.

S8, depositing a passivation film on the back surface: depositing Al on the back of the annealed silicon wafer by adopting a PECVD two-in-one machine ₂ O ₃ /SiN _x And (3) a composite film layer.

S9, depositing an antireflection film on the front surface: depositing SiN on the front surface of a silicon wafer with back surface coating completed by adopting PECVD two-in-one machine _x /SiO _x Ny/SiO _x And (3) a composite film layer. And (3) the deposition temperature is kept at 520 ℃, and a nitride film layer, a silicon oxynitride film layer and a silicon oxide film layer with different thicknesses and refractive indexes are sequentially deposited under vacuum conditions, so that the antireflection laminated film is finally formed. The refractive index and thickness of the silicon nitride film layer are controlled by the ratio of the flow rate of the introduced gas, the time, the gas pressure, the power and the duty ratio. Wherein the refractive index of the first film body close to the surface of the silicon substrate is 2.28, the thickness is 12nm, the silane flow rate is 1600sccm, the ammonia flow rate is 6000sccm, the phosphane flow rate is 7800sccm, the deposition time is 110s, the pressure is 220Pa, the power is 11500W, and the duty ratio is 7:98. then, a second film body with a refractive index of 2.20, a thickness of 8nm, a silane flow rate of 1500sccm, an ammonia flow rate of 7200sccm, a deposition time of 80s, a pressure of 220Pa, a power of 12000W and a duty ratio of 7:98. the refractive index of the redeposited third film body is 2.15, the thickness is 10nm, the silane flow rate is 1200sccm, the ammonia flow rate is 9000sccm, the deposition time is 120s, the pressure is 230Pa, the power is 12000W, and the duty ratio is 7:77. the refractive index of the deposited fourth film body is 2.03, the thickness is 15nm, the silane flow rate is 900sccm, the ammonia flow rate is 9500sccm, the deposition time is 175s, the pressure is 230Pa, the power is 12000W, and the duty ratio is 7:77. depositing a layer again 18nm of a fifth film body, a refractive index of 1.86, a silane flow rate of 950sccm, an ammonia flow rate of 1400sccm, a laughing gas flow rate of 7000sccm, a deposition time of 270s, a pressure of 130Pa, a power of 11000W, and a duty ratio of 6:96; finally, a layer of sixth film body is deposited on the surface layer, the thickness is 15nm, the refractive index is 1.45, the silane flow rate is 450sccm, the laughing gas flow rate is 9000sccm, the deposition time is 210s, the pressure is 130Pa, the power is 11000W, and the duty ratio is 6:90. wherein the phosphane gas used is at a pH of 2% ₃ And 98% H ₂ The total film thickness was 78nm.

S10, back laser: and carrying out back laser perforating according to the back graphic design, wherein the back auxiliary grid region is subjected to laser perforating to increase contact, and the aluminum main grid and the back electrode region are not subjected to laser.

S11, preparing a back electrode: and (3) adopting a screen printing mode, selecting silver paste on the silicon wafer subjected to back laser grooving, and printing a back silver electrode and PAD points.

S12, preparing a back surface electric field: aluminum paste is selected, and a screen plate with 360 meshes, a wire diameter of 16 mu m, a yarn thickness of 28 mu m and a film thickness of 16 mu m is adopted to synchronously print an aluminum main grid and an aluminum auxiliary grid in a screen printing mode.

S13, printing a positive electrode main grid region: and preparing the front electrode by screen printing on the silicon wafer printed with the back electrode by adopting front silver paste.

S14, printing a front side auxiliary grid region: the front side auxiliary grid is printed by adopting positive silver paste according to the pattern of the screen plate, and the screen plate with 520 meshes, 17 mu m of line diameter, 11 mu m of yarn thickness and 6 mu m of film thickness is adopted.

S15, sintering: and (3) co-sintering the silicon wafer printed with the front electrode, wherein the sintering peak temperature is 780 ℃.

S16, electric injection: and carrying out electric injection treatment on the sintered battery piece.

S17, a finished product: and testing, sorting, packaging and warehousing the battery pieces of the products.

Example 2

The solar cell comprises a silicon substrate and an antireflection film attached to the silicon substrate, wherein the antireflection film in the embodiment comprises a first phosphorus-doped silicon nitride antireflection film, a second phosphorus-doped silicon nitride antireflection film, a third silicon nitride antireflection film, a fourth silicon nitride antireflection film, a silicon oxynitride antireflection film and a silicon oxide antireflection film which are stacked layer by layer.

The preparation method comprises the following steps:

S9, depositing an antireflection film on the front surface: depositing SiN on the front surface of a silicon wafer with back surface coating completed by adopting PECVD two-in-one machine _x /SiO _x Ny/SiO _x And (3) a composite film layer. The deposition temperature is kept at 520 ℃, and different thicknesses and refractive indexes are sequentially deposited under vacuum conditionsAnd finally forming the antireflection laminated film by the nitride film layer, the silicon oxynitride film layer and the silicon oxide film layer. The refractive index and thickness of the silicon nitride film layer are controlled by the ratio of the flow rate of the introduced gas, the time, the gas pressure, the power and the duty ratio. Wherein the refractive index of the first film body close to the surface of the silicon substrate is 2.28, the thickness is 12nm, the silane flow rate is 1600sccm, the ammonia flow rate is 6000sccm, the phosphane flow rate is 6800sccm, the deposition time is 110s, the pressure is 220Pa, the power is 11500W, and the duty ratio is 7:98. then, a second film body with a refractive index of 2.20, a thickness of 8nm, a silane flow rate of 1500sccm, an ammonia flow rate of 7200sccm, a phosphane flow rate of 6400sccm, a deposition time of 80s, a pressure of 220Pa, a power of 12000W and a duty ratio of 7:98. the refractive index of the redeposited third film body is 2.15, the thickness is 10nm, the silane flow rate is 1200sccm, the ammonia flow rate is 9000sccm, the deposition time is 120s, the pressure is 230Pa, the power is 12000W, and the duty ratio is 7:77. the refractive index of the deposited fourth film body is 2.03, the thickness is 15nm, the silane flow rate is 900sccm, the ammonia flow rate is 9500sccm, the deposition time is 175s, the pressure is 230Pa, the power is 12000W, and the duty ratio is 7:77. a layer of 18nm fifth film body is deposited, the refractive index is 1.86, the silane flow rate is 950sccm, the ammonia flow rate is 1400sccm, the laughing gas flow rate is 7000sccm, the deposition time is 270s, the pressure is 130Pa, the power is 11000W, and the duty ratio is 6:96; finally, a layer of sixth film body is deposited on the surface layer, the thickness is 15nm, the refractive index is 1.45, the silane flow rate is 450sccm, the laughing gas flow rate is 9000sccm, the deposition time is 210s, the pressure is 130Pa, the power is 11000W, and the duty ratio is 6:90. wherein the phosphane gas used is at a pH of 2% ₃ And 98% H ₂ The total film thickness was 78nm.

Example 3

The solar cell comprises a silicon substrate and an antireflection film attached to the silicon substrate, wherein the antireflection film in the embodiment comprises a first phosphorus-doped silicon nitride antireflection film, a second phosphorus-doped silicon nitride antireflection film, a third phosphorus-doped silicon nitride antireflection film, a fourth phosphorus-doped silicon nitride antireflection film, a silicon oxynitride antireflection film and a silicon oxide antireflection film which are stacked layer by layer.

The preparation method comprises the following steps:

S9, depositing an antireflection film on the front surface: depositing SiN on the front surface of a silicon wafer with back surface coating completed by adopting PECVD two-in-one machine _x /SiO _x Ny/SiO _x And (3) a composite film layer. And (3) the deposition temperature is kept at 520 ℃, and a nitride film layer, a silicon oxynitride film layer and a silicon oxide film layer with different thicknesses and refractive indexes are sequentially deposited under vacuum conditions, so that the antireflection laminated film is finally formed. The refractive index and thickness of the silicon nitride film layer are controlled by the ratio of the flow rate of the introduced gas, the time, the gas pressure, the power and the duty ratio. Wherein the refractive index of the first film body close to the surface of the silicon substrate is 2.28, the thickness is 12nm, the silane flow rate is 1600sccm, the ammonia flow rate is 6000sccm, the phosphane flow rate is 6800sccm, the deposition time is 110s, the pressure is 220Pa, the power is 11500W, and the duty ratio is 7:98. then, a second film body with a refractive index of 2.20, a thickness of 8nm, a silane flow rate of 1500sccm, an ammonia flow rate of 7200sccm, a phosphane flow rate of 6400sccm, a deposition time of 80s, a pressure of 220Pa, a power of 12000W and a duty ratio of 7:98. the refractive index of the redeposited third film body is 2.15, the thickness is 10nm, the silane flow rate is 1200sccm, the ammonia flow rate is 9000sccm, the phosphane flow rate is 6000sccm, the deposition time is 120s, the pressure is 230Pa, the power is 12000W, and the duty ratio is 7:77. the refractive index of the deposited fourth film body is 2.03, the thickness is 15nm, the silane flow rate is 900sccm, the ammonia flow rate is 9500sccm, the phosphane flow rate is 6000sccm, the deposition time is 175s, the pressure is 230Pa, the power is 12000W, and the duty ratio is 7:77. depositing a fifth 18nm film Bulk, refractive index 1.86, silane flow 950sccm, ammonia flow 1400sccm, laughing gas flow 7000sccm, deposition time 270s, pressure 130Pa, power 11000W, duty cycle 6:96; finally, a layer of sixth film body is deposited on the surface layer, the thickness is 15nm, the refractive index is 1.45, the silane flow rate is 450sccm, the laughing gas flow rate is 9000sccm, the deposition time is 210s, the pressure is 130Pa, the power is 11000W, and the duty ratio is 6:90. wherein the phosphane gas used is at a pH of 2% ₃ And 98% H ₂ The total film thickness was 78nm.

Example 4

The solar cell comprises a silicon substrate and an antireflection film attached to the silicon substrate, wherein the antireflection film in the embodiment comprises a first phosphorus-doped silicon nitride antireflection film, a second phosphorus-doped silicon nitride antireflection film, a third phosphorus-doped silicon nitride antireflection film, a fourth phosphorus-doped silicon nitride antireflection film, a phosphorus-doped silicon oxynitride antireflection film and a phosphorus-doped silicon oxide antireflection film which are stacked layer by layer.

The preparation method comprises the following steps:

S9, depositing an antireflection film on the front surface: depositing SiN on the front surface of a silicon wafer with back surface coating completed by adopting PECVD two-in-one machine _x /SiO _x Ny/SiO _x And (3) a composite film layer. The deposition temperature is kept at 520 ℃, and different thicknesses are sequentially deposited under vacuum conditionAnd finally forming the antireflection laminated film by the nitride film layer, the silicon oxynitride film layer and the silicon oxide film layer with refractive indexes. The refractive index and thickness of the silicon nitride film layer are controlled by the ratio of the flow rate of the introduced gas, the time, the gas pressure, the power and the duty ratio. Wherein the refractive index of the first film body close to the surface of the silicon substrate is 2.28, the thickness is 12nm, the silane flow rate is 1600sccm, the ammonia flow rate is 6000sccm, the phosphane flow rate is 6800sccm, the deposition time is 110s, the pressure is 220Pa, the power is 11500W, and the duty ratio is 7:98. then, a second film body with a refractive index of 2.20, a thickness of 8nm, a silane flow rate of 1500sccm, an ammonia flow rate of 7200sccm, a phosphane flow rate of 6400sccm, a deposition time of 80s, a pressure of 220Pa, a power of 12000W and a duty ratio of 7:98. the refractive index of the redeposited third film body is 2.15, the thickness is 10nm, the silane flow rate is 1200sccm, the ammonia flow rate is 9000sccm, the phosphane flow rate is 6000sccm, the deposition time is 120s, the pressure is 230Pa, the power is 12000W, and the duty ratio is 7:77. the refractive index of the deposited fourth film body is 2.03, the thickness is 15nm, the silane flow rate is 900sccm, the ammonia flow rate is 9500sccm, the phosphane flow rate is 6000sccm, the deposition time is 175s, the pressure is 230Pa, the power is 12000W, and the duty ratio is 7:77. a layer of 18nm fifth film body is deposited, the refractive index is 1.86, the silane flow rate is 950sccm, the ammonia flow rate is 1400sccm, the laughing gas flow rate is 7000sccm, the phosphane flow rate is 4000sccm, the deposition time is 270s, the pressure is 130Pa, the power is 11000W, and the duty ratio is 6:96; finally, a layer of sixth film body is deposited on the surface layer, the thickness is 15nm, the refractive index is 1.45, the silane flow is 450sccm, the laughing gas flow is 9000sccm, the phosphane flow is 3000sccm, the deposition time is 210s, the pressure is 130Pa, the power is 11000W, and the duty ratio is 6:90. wherein the phosphane gas used is at a pH of 2% ₃ And 98% H ₂ The total film thickness was 78nm.

Example 5

The preparation method comprises the following steps:

S9, depositing an antireflection film on the front surface: depositing SiN on the front surface of a silicon wafer with back surface coating completed by adopting PECVD two-in-one machine _x /SiO _x Ny/SiO _x And (3) a composite film layer. And (3) the deposition temperature is kept at 520 ℃, and a nitride film layer, a silicon oxynitride film layer and a silicon oxide film layer with different thicknesses and refractive indexes are sequentially deposited under vacuum conditions, so that the antireflection laminated film is finally formed. The refractive index and thickness of the silicon nitride film layer are controlled by the ratio of the flow rate of the introduced gas, the time, the gas pressure, the power and the duty ratio. The refractive index of the first film body close to the surface of the silicon substrate is 2.28, the thickness is 12nm, the silane flow rate is 1600sccm, the ammonia flow rate is 6000sccm, the phosphane flow rate is 9000sccm, the deposition time is 110s, the pressure is 220Pa, the power is 11500W, and the duty ratio is 7:98. then, a second film body with a refractive index of 2.20, a thickness of 8nm, a silane flow rate of 1500sccm, an ammonia flow rate of 7200sccm, a phosphine flow rate of 8700sccm, a deposition time of 80s, a pressure of 220Pa, a power of 12000W, and a duty ratio of 7:98. the refractive index of the redeposited third film body is 2.15, the thickness is 10nm, the silane flow rate is 1200sccm, the ammonia flow rate is 9000sccm, the phosphane flow rate is 8100sccm, the deposition time is 120s, the pressure is 230Pa, the power is 12000W, and the duty ratio is 7:77. depositing a fourth film with a refractive index of 2.03, a thickness of 15nm, a silane flow rate of 900sccm, an ammonia flow rate of 9500sccm, and a phosphane Flow rate is 8000sccm, deposition time is 175s, pressure is 230Pa, power is 12000W, duty ratio is 7:77. a layer of 18nm fifth film body is deposited, the refractive index is 1.86, the silane flow rate is 950sccm, the ammonia flow rate is 1400sccm, the laughing gas flow rate is 7000sccm, the deposition time is 270s, the pressure is 130Pa, the power is 11000W, and the duty ratio is 6:96; finally, a layer of sixth film body is deposited on the surface layer, the thickness is 15nm, the refractive index is 1.45, the silane flow rate is 450sccm, the laughing gas flow rate is 9000sccm, the deposition time is 210s, the pressure is 130Pa, the power is 11000W, and the duty ratio is 6:90. wherein the phosphane gas used is at a pH of 2% ₃ And 98% H ₂ The total film thickness was 78nm.

Example 6

The preparation method comprises the following steps:

S9, depositing an antireflection film on the front surface: depositing SiN on the front surface of a silicon wafer with back surface coating completed by adopting PECVD two-in-one machine _x /SiO _x Ny/SiO _x And (3) a composite film layer. And (3) the deposition temperature is kept at 520 ℃, and a nitride film layer, a silicon oxynitride film layer and a silicon oxide film layer with different thicknesses and refractive indexes are sequentially deposited under vacuum conditions, so that the antireflection laminated film is finally formed. The refractive index and thickness of the silicon nitride film layer are controlled by the ratio of the flow rate of the introduced gas, the time, the gas pressure, the power and the duty ratio. Wherein, the refractive index of the first film body close to the surface of the silicon substrate is 2.28, the thickness is 12nm, the silane flow rate is 1600sccm, the ammonia flow rate is 6000sccm, the phosphane flow rate is 1800sccm, the deposition time is 110s, the pressure is 220Pa, the power is 11500W, and the duty ratio is 7:98. then, a second film body with a refractive index of 2.20, a thickness of 8nm, a silane flow rate of 1500sccm, an ammonia flow rate of 7200sccm, a phosphine flow rate of 1500sccm, a deposition time of 80s, a pressure of 220Pa, a power of 12000W and a duty ratio of 7:98. the refractive index of the redeposited third film body is 2.15, the thickness is 10nm, the silane flow rate is 1200sccm, the ammonia flow rate is 9000sccm, the phosphane flow rate is 1400sccm, the deposition time is 120s, the pressure is 230Pa, the power is 12000W, and the duty ratio is 7:77. the refractive index of the deposited fourth film body is 2.03, the thickness is 15nm, the silane flow rate is 900sccm, the ammonia flow rate is 9500sccm, the phosphane flow rate is 1400sccm, the deposition time is 175s, the pressure is 230Pa, the power is 12000W, and the duty ratio is 7:77. a layer of 18nm fifth film body is deposited, the refractive index is 1.86, the silane flow rate is 950sccm, the ammonia flow rate is 1400sccm, the laughing gas flow rate is 7000sccm, the deposition time is 270s, the pressure is 130Pa, the power is 11000W, and the duty ratio is 6:96; finally, a layer of sixth film body is deposited on the surface layer, the thickness is 15nm, the refractive index is 1.45, the silane flow rate is 450sccm, the laughing gas flow rate is 9000sccm, the deposition time is 210s, the pressure is 130Pa, the power is 11000W, and the duty ratio is 6:90. wherein the phosphane gas used is at a pH of 2% ₃ And 98% H ₂ The total film thickness was 78nm.

Comparative example 1

The solar cell comprises a silicon substrate and an antireflection film attached to the silicon substrate, wherein the antireflection film in the embodiment comprises a first silicon nitride antireflection film, a second silicon nitride antireflection film, a third silicon nitride antireflection film, a fourth silicon nitride antireflection film, a silicon oxynitride antireflection film and a silicon oxide antireflection film which are stacked layer by layer.

The preparation method comprises the following steps:

S9, depositing an antireflection film on the front surface: depositing SiN on the front surface of a silicon wafer with back surface coating completed by adopting PECVD two-in-one machine _x /SiO _x N _y /SiO _x And (3) a composite film layer. And (3) the deposition temperature is kept at 520 ℃, and a nitride film layer, a silicon oxynitride film layer and a silicon oxide film layer with different thicknesses and refractive indexes are sequentially deposited under vacuum conditions, so that the antireflection laminated film is finally formed. The refractive index and thickness of the silicon nitride film layer are controlled by the ratio of the flow rate of the introduced gas, the time, the gas pressure, the power and the duty ratio. The refractive index of the first film body close to the surface of the silicon substrate is 2.28, the thickness is 12nm, the silane flow rate is 1600sccm, the ammonia flow rate is 6000sccm, the deposition time is 110s, the pressure is 220Pa, the power is 11500W, and the duty ratio is 7:98. then, a second film body with a refractive index of 2.20, a thickness of 8nm, a silane flow rate of 1500sccm, an ammonia flow rate of 7200sccm, a deposition time of 80s, a pressure of 220Pa, a power of 12000W and a duty ratio of 7:98. the refractive index of the redeposited third film body is 2.15, the thickness is 10nm, the silane flow rate is 1200sccm, the ammonia flow rate is 9000sccm, the deposition time is 120s, the pressure is 230Pa, the power is 12000W, and the duty ratio is 7:77. depositing a fourth film with a refractive index of 2.03, a thickness of 15nm, a silane flow rate of 900sccm, an ammonia flow rate of 9500sccm, a deposition time of 175s, a pressure of 230Pa, a power of 12000W, Duty cycle 7:77. a layer of 18nm fifth film body is deposited, the refractive index is 1.86, the silane flow rate is 950sccm, the ammonia flow rate is 1400sccm, the laughing gas flow rate is 7000sccm, the deposition time is 270s, the pressure is 130Pa, the power is 11000W, and the duty ratio is 6:96; finally, a layer of sixth film body is deposited on the surface layer, the thickness is 15nm, the refractive index is 1.45, the silane flow rate is 450sccm, the laughing gas flow rate is 9000sccm, the deposition time is 210s, the pressure is 130Pa, the power is 11000W, and the duty ratio is 6:90. the total film thickness was 78nm.

The main parameter controls for examples 1-6 and comparative example 1 are shown in the following table:

the test results of the provided batteries of examples 1 to 6 and comparative example 1 are shown in the following table:

the conversion efficiency Eta, the open-circuit voltage Uoc, the short-circuit current Isc, the filling factor FF, the leakage current IRev2, the series resistance Rs and the parallel resistance Rsh are obtained by testing through a halm tester under the condition of calibration of a label. The contact resistance is obtained by a contact resistance tester through TLM method test.

The method provided by the embodiment of the application can reduce the contact resistance by 3% -12%, and particularly the method provided by the embodiment 1-4 can not cause the increase of surface recombination on the basis of reducing the contact resistance, and has no negative effects on the open voltage and the current.

The front side reflectance test was performed on example 3 and comparative example 1, and as shown in fig. 2, it was found that the reflectance of the antireflection film was not greatly affected after phosphorus doping.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A solar cell, the solar cell comprising:

a silicon substrate;

the anti-reflection film is attached to the silicon substrate and comprises at least one layer of film body, wherein at least one layer of film body in the anti-reflection film is a phosphorus-doped anti-reflection film; and

and the electrode penetrates through the anti-reflection film to form ohmic contact with the silicon substrate, and a phosphorus-containing silver-silicon alloy is formed at the contact part of the electrode and the silicon substrate.

2. The solar cell of claim 1, wherein the phosphorous doped anti-reflective film comprises a phosphorous doped silicon nitride anti-reflective film, a phosphorous doped silicon oxynitride anti-reflective film, or a phosphorous doped silicon oxide anti-reflective film.

3. The solar cell of claim 1, wherein the phosphorus-doped anti-reflection film has a phosphorus content of 0.5% -5% by volume;

preferably, the volume content of phosphorus in the phosphorus-doped anti-reflection film is 1.5% -4%;

4. The solar cell of claim 1, wherein the refractive index of each of the film bodies in the anti-reflection film is different.

5. The solar cell according to claim 4, wherein the refractive index of the film body gradually decreases in the inside-out direction.

6. The solar cell according to claim 1, wherein at least one of the anti-reflection films has a silicon nitride anti-reflection film; and/or

At least one layer of film body in the antireflection film is a silicon oxide antireflection film;

preferably, the antireflection film comprises a first phosphorus-doped silicon nitride antireflection film, a second phosphorus-doped silicon nitride antireflection film, a third phosphorus-doped silicon nitride antireflection film, a fourth phosphorus-doped silicon nitride antireflection film, a silicon oxynitride antireflection film and a silicon oxide antireflection film which are stacked layer by layer along the direction from inside to outside.

7. A method of manufacturing a solar cell, the method comprising:

obtaining a silicon substrate to be treated;

depositing an antireflection film on the silicon substrate, wherein the antireflection film comprises at least one layer of film body, and at least one layer of film body in the antireflection film is a phosphorus-doped antireflection film;

8. The method for manufacturing a solar cell according to claim 7, wherein the method for manufacturing a phosphorus-doped antireflection film comprises:

9. The method of manufacturing a solar cell according to claim 8, wherein the phosphorus-containing gas includes at least one of phosphane, phosphorus trifluoride, and phosphorus pentafluoride.

10. The method of claim 8, wherein the flow rate of the phosphorus-containing gas is 2000-8000sccm.