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CN110854240A - PERC battery and preparation method thereof - Google Patents

PERC battery and preparation method thereof Download PDF

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Publication number
CN110854240A
CN110854240A CN201911256027.6A CN201911256027A CN110854240A CN 110854240 A CN110854240 A CN 110854240A CN 201911256027 A CN201911256027 A CN 201911256027A CN 110854240 A CN110854240 A CN 110854240A
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layer
silicon
phosphorus
doped
silicon dioxide
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张鹏
张忠文
王永谦
尹丙伟
王岚
王璞
丁蕾
眭山
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Tongwei Solar Meishan Co Ltd
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Tongwei Solar Meishan Co Ltd
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H01L31/1804Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof comprising only elements of Group IV of the Periodic Table
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02Details
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    • H01L31/02161Coatings for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/02167Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
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    • H01L31/035272Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions characterised by at least one potential jump barrier or surface barrier
    • H01L31/03529Shape of the potential jump barrier or surface barrier
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/06Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers
    • H01L31/068Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
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    • H01L31/186Particular post-treatment for the devices, e.g. annealing, impurity gettering, short-circuit elimination, recrystallisation
    • H01L31/1868Passivation
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    • Y02E10/547Monocrystalline silicon PV cells
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
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Abstract

The application provides a PERC battery and a preparation method thereof, and belongs to the technical field of photovoltaic batteries. The preparation method comprises the steps of texturing, diffusion, etching, back polishing, annealing, back coating and front coating. The back surface coating step comprises: and introducing ozone gas into the equipment provided with the annealed silicon wafer for oxidation treatment, so that a back silicon dioxide layer is formed on the back of the silicon wafer. And then continuously introducing ozone serving as an oxygen source in the same equipment, adding an aluminum source, and depositing a back aluminum oxide layer on the back silicon dioxide layer. A back side silicon nitride layer is deposited on the back side aluminum oxide layer. According to the preparation method, the back silicon oxide layer is formed by introducing ozone, the ozone is used as an oxygen source, the back aluminum oxide layer can be continuously deposited in the ozone introducing equipment, the back silicon dioxide layer and the back aluminum oxide layer can be formed in the same equipment, ozone oxidation equipment does not need to be added, the cleanliness of a film contact interface is kept, and the PID (proportion integration differentiation) performance of the PERC battery can be improved.

Description

PERC battery and preparation method thereof
Technical Field
The application relates to the technical field of photovoltaic cells, in particular to a PERC cell and a preparation method thereof.
Background
PERC (Passivated emitter and Rear Cell) has gained wide attention in the industry due to its high conversion efficiency. The core of the technology is that the back of a silicon chip is covered by an aluminum oxide or silicon oxide film to play a role in passivating the back surface and improving long-wave response, so that the conversion efficiency of the battery is improved.
The back of the silicon wafer is coated with an alumina film to passivate the silicon. However, the matching between the back side alumina film and silicon is not good, and after passivation by the alumina film, the back side still has larger defects, and the passivation effect is general.
In order to enhance the chemical passivation effect of the back surface of the silicon wafer, CN106992229A discloses a passivation process for the back surface of a PERC cell, in which a silicon dioxide layer is formed on the back surface of the silicon wafer by an ozone machine, an aluminum oxide film is deposited on the silicon dioxide layer by ALD equipment, and then a silicon nitride layer is deposited on the aluminum oxide film by a plasma enhanced chemical vapor deposition method.
Disclosure of Invention
The PERC battery and the preparation method thereof have the advantages that the process compatibility is stronger, the battery production cost is reduced, the conversion efficiency of the battery can be improved, and the reliability of the battery is improved.
The embodiment of the application provides a preparation method of a PERC battery, which comprises the steps of texturing, diffusion, etching, back polishing, annealing, back film coating and front film coating. The back surface coating step comprises: and introducing ozone gas into the equipment provided with the annealed silicon wafer for oxidation treatment, so that a back silicon dioxide layer is formed on the back of the silicon wafer. And then continuously introducing ozone serving as an oxygen source in the same equipment, adding an aluminum source, and depositing a back aluminum oxide layer on the back silicon dioxide layer. A back side silicon nitride layer is deposited on the back side aluminum oxide layer.
The inventors have found that CN106992229A discloses a passivation process for the back surface of a PERC cell resulting in a PERC cell with poor PID performance. Therefore, the inventors have made intensive studies and found that the formation of a silicon oxide layer is carried out in an ozone machine, the deposition of an alumina thin film is carried out in an ALD apparatus, both processes need to be carried out in two apparatuses, and the cleanliness of a film layer contact interface is affected during the transfer of a silicon wafer from the ozone machine to the ALD apparatus. In the prior art, oxygen is introduced into the ALD equipment as an oxygen source when the back side alumina layer is prepared, so that the preparation of the back side silica layer and the back side alumina layer in CN106992229A is performed in two equipment.
The preparation method of the PERC battery provided by the embodiment of the application has the beneficial effects that: the silicon dioxide layer obtained can be made denser by introducing ozone into the apparatus to deposit the back silicon dioxide layer. And then, ozone is used as an oxygen source in the same equipment, the back alumina layer is continuously deposited, two processes can be carried out in the same equipment, ozone oxidation equipment is not required to be added, the cleanliness of a film layer contact interface can be kept, and the reliability and the conversion efficiency of the battery are improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments are briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive efforts and also belong to the protection scope of the present application.
Fig. 1 is a schematic structural diagram of a single-sided PERC cell provided in an embodiment of the present application;
fig. 2 is a schematic structural diagram of a double-sided PERC battery provided in an embodiment of the present application;
icon: a 10-P type silicon substrate; a 20-N + emitter junction layer; a 30-N + + silicon layer; 40-front side silicon dioxide layer; 50-a back side silicon dioxide layer; 60-back side alumina layer; 70-a back side silicon nitride layer; 80-front antireflection layer; 90-front electrode; 91-aluminum back field; 92-aluminum grid line.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
Fig. 1 is a schematic structural diagram of a single-sided PERC cell provided in an embodiment of the present application; fig. 2 is a schematic structural diagram of a double-sided PERC battery provided in an embodiment of the present application. Referring to fig. 1 and 2, in an embodiment of the present application, a method for manufacturing a PERC battery includes the following steps:
s10, texturing: and cleaning and texturing the silicon wafer, removing a damage layer on the surface of the silicon wafer, and texturing the front side of the silicon wafer to form a pyramid textured surface with the height of 0.5-5 microns. Optionally, the height of the texture is 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, or 5 μm. Alternatively, the silicon wafer provided by the embodiment of the present application is a single crystal silicon wafer, and the texturing is performed by using an alkali solution (e.g., strong alkali, NaOH or KOH). In other embodiments, the silicon wafer is a polycrystalline silicon wafer and is textured using an acid solution (e.g., a strong acid, nitric acid or/and hydrofluoric acid).
S20, diffusion: and doping phosphorus on the textured silicon wafer to form a phosphorus-doped N + emitter junction layer 20. Optionally, the silicon wafer is placed in a diffusion furnace, and diffusion is performed for 30-60min at the diffusion temperature of 750-850 ℃, so that a doping source is deposited on the front surface of the silicon wafer and thermal diffusion is performed to prepare a phosphorus-doped N + emitter junction 20, thereby forming a PN junction. Wherein the doping source is phosphorus oxychloride (POCl)3) The solution has a diffusion temperature of 750 deg.C, 780 deg.C,800 ℃, 820 ℃ or 850 ℃; the diffusion time may be 30min, 40min, 50min or 60 min. The thickness of the phosphorus doped N + emitter junction layer 20 formed is 0.2-0.4 μm. For example: the thickness of the phosphorus doped N + emitter junction layer 20 may be 0.2 μm, 0.3 μm, or 0.4 μm.
S30, heavily doped: local region doping diffusion is performed on the phosphorus-doped N + emitter junction layer 20, so that a phosphorus-doped N + + silicon layer 30 is formed between the N + emitter junction layer 20 and the silicon wafer (i.e., the P-type silicon substrate 10). High-concentration doping (phosphorus-doped N + + silicon layer 30) is carried out at the contact part of the metal grid line and the silicon wafer and the vicinity thereof, and low-concentration doping (phosphorus-doped N + emitter junction layer 20) is carried out in the region except the front electrode 90, so that the contact resistance between the silicon wafer and the electrode is reduced, the surface recombination is reduced, and the minority carrier lifetime is prolonged. Thereby reducing series resistance and improving filling factor; the carrier recombination is reduced, and the surface passivation effect is improved; the short-wave spectral response of the battery is enhanced, and the short-circuit current and the open-circuit voltage are improved.
Alternatively, a phosphorus doped N + + silicon layer 30 (heavily doped silicon layer) is formed using laser doping. In the laser doping process, the surface of a silicon wafer is melted by using the heat effect of laser, phosphorus atoms in phosphorosilicate glass covering the top of an emitter enter the surface layer of the silicon wafer to perform doping and diffusion in a local area, the diffusion coefficient of the phosphorus atoms in liquid silicon is higher than that in solid silicon, and the phosphorus atoms are doped to replace the positions of silicon atoms after solidification to form a heavily doped silicon layer. Wherein the laser power is 20-40W. For example: the laser power may be 20W, 25W, 30W, 35W or 40W. S40, etching and back polishing: and cleaning and back polishing the laser-doped silicon wafer. After the diffusion process, N-type layers are formed on the front surface, the back surface and the edge of the silicon wafer, and phosphorosilicate glass is arranged on the surface of the silicon wafer, so that the N-type layers on the edge and the back surface of the silicon wafer are removed through a wet etching process, the phosphorosilicate glass on the front surface is removed, and the back surface of the silicon wafer is polished. Wherein, the etching solution used in the wet etching is HNO3And a mixed solution of HF.
S50, annealing: putting the silicon chip into an annealing furnace, and introducing a certain amount of oxygen during annealing so as to be capable of forming a P-doped N + emitter junction layerGrowing a front side silicon dioxide layer 40 (SiO)2). Wherein the annealing temperature is 750-850 ℃. For example: the annealing temperature is 750 deg.C, 770 deg.C, 790 deg.C, 810 deg.C, 830 deg.C or 850 deg.C. The front-side silicon dioxide layer 40 is formed to a thickness of 2-5 nm. For example: the thickness of the front-side silicon dioxide layer 40 is 2nm, 3nm, 4nm or 5 nm.
S60, back coating: depositing a back silicon dioxide layer 50 (SiO) on the back of the silicon wafer2) A back aluminum oxide layer 60(AlOx), and a back silicon nitride layer 70 (SiNx). Optionally, the back silicon oxide layer 50 and the back aluminum oxide layer 60 are performed in the chamber of the same apparatus, for example: are all performed in the chamber of the ALD apparatus. And placing the annealed silicon wafer into a chamber of an ALD (atomic layer deposition) device, and introducing ozone gas into the chamber of the ALD device to perform oxidation treatment, so that a back silicon dioxide layer 50 is formed on the back of the polished silicon wafer. Then continuing to perform a passivation process in the ALD equipment, continuing to introduce ozone into the ALD equipment as an oxygen source, adding an aluminum source, and depositing a back aluminum oxide layer 60 on the surface of the back silicon dioxide layer 50 away from the silicon wafer. The back silicon dioxide layer 50 is deposited between the back aluminum oxide layer 60 and the silicon wafer, so that the comprehensive utilization rate of passivation and incident light can be effectively enhanced, and the loss of non-equilibrium carriers caused by surface defects can be reduced. The short-circuit current and the open-circuit voltage of the battery are improved, and the light attenuation resistance, the PID resistance and the reliability of the battery with the structure are improved.
The two processes of depositing the back silicon dioxide layer 50 and depositing the back aluminum oxide layer 60 are carried out in the same equipment, so that the compatibility of the processes is better, the formation of the back silicon dioxide layer 50 is carried out without additionally adding ozone oxidation equipment, the contact interface cleanliness of the back silicon dioxide layer 50 and the back aluminum oxide layer 60 can be kept, and the conversion efficiency of the battery is improved. Ozone gas is introduced into a cavity of the ALD device, so that the ozone gas and silicon are subjected to oxidation reaction, the obtained back silicon dioxide layer 50 is better in compactness, the back defects of the battery can be further improved, and the PID resistance of the battery is improved.
Wherein the thickness of the back silicon dioxide layer 50 is 2-5 nm. The thickness of the back alumina layer 60 is 2-6 nm. Alternatively, the thickness of the back side silicon dioxide layer 50 may be 2nm, 3nm, 4nm, or 5 nm; the thickness of the back aluminum oxide layer 60 may be 2nm, 3nm, 4nm, 5nm, or 6 nm.
In order to deposit the back silicon dioxide layer 50 on the back surface of the silicon wafer, the conditions for introducing ozone gas into the chamber of the ALD apparatus to perform the oxidation treatment include: the flow rate of the ozone is 5-150sccm, the oxidation time is 1-10min, and the oxidation temperature is 150-. For example: the flow rate of the introduced ozone gas can be 5sccm, 10sccm, 20sccm, 40sccm, 80sccm, 120sccm or 150 sccm; the oxidation time can be 1min, 3min, 5min, 7min, 9min or 10 min; the oxidation temperature may be 150 ℃, 200 ℃, 250 ℃ or 300 ℃.
Further, the deposition of the back side alumina layer 60 may continue in the chamber of the ALD apparatus. Wherein, in the process of depositing the back side alumina layer 60, the introduced ozone gas is directly used as an oxygen source, and the deposition is carried out at the temperature of 150 ℃ and 300 ℃.
The aluminum source for depositing the back aluminum oxide layer 60 is an aluminum-containing precursor, and may be one or more of aluminum trichloride, trimethylaluminum, triethylaluminum, dimethylaluminum chloride, aluminum ethoxide and aluminum isopropoxide, and is formed by an Atomic Layer Deposition (ALD) method. The Atomic Layer Deposition (ALD) method is carried out in the cavity of the ALD device, ozone gas is introduced into the cavity of the ALD device, two processes can be compatible in the same device, and the production cost is reduced.
Further, a back silicon nitride layer 70 is deposited on the back aluminum oxide layer 60. Alternatively, the deposition method of the back silicon nitride layer 70 may be an atomic layer deposition method or a Plasma Enhanced Chemical Vapor Deposition (PECVD) method.
With continued reference to fig. 1 and 2, if the prepared PERC cell is a single-sided cell, the thickness of the back silicon nitride layer 70 is 110-180 nm. For example: the thickness of the back side silicon nitride layer 70 may be 110nm, 130nm, 150nm, 170nm or 180 nm. If the prepared PERC cell is a bifacial cell, the thickness of the back silicon nitride layer 70 is 85-105 nm. For example: the thickness of the back side silicon nitride layer 70 may be 85nm, 90nm, 95nm, 100nm or 105 nm.
S70, front film coating: and forming a front silicon nitride layer on the front surface of the silicon wafer. A front silicon nitride (SiNx) layer (a front antireflection layer 80) is formed on a front silicon dioxide layer of a silicon wafer by adopting a Plasma Enhanced Chemical Vapor Deposition (PECVD) method, so that the light reflectivity is reduced, and a certain passivation effect is achieved. Optionally, the front side silicon nitride layer has a thickness of 73-83 nm. For example: the thickness of the front side silicon nitride layer may be 73nm, 75nm, 77nm, 79nm, 81nm or 83 nm.
S80, laser grooving: and selectively etching part of the passivation layer (the back silicon dioxide layer, the back aluminum oxide layer and the back silicon nitride layer) on the back of the silicon chip by adopting laser etching, so as to open a groove or a hole on the back of the silicon chip and expose the structure of the P-type silicon substrate layer.
S90, screen printing and sintering: and printing silver paste on the front surface of the silicon wafer and aluminum paste on the back surface of the silicon wafer according to the screen printing plate pattern design by adopting a screen printing method, and forming ohmic contact after high-temperature sintering to manufacture the PERC battery.
Optionally, the front side printed silver paste is sintered to form the front side electrode 90, and the front side electrode 90 is in ohmic contact with the phosphorus doped N + + silicon layer 30. Wherein the front electrode 90 is a front grid line, the height of the front grid line is 18-25 μm, and the width is 35-45 μm. For example: the height of the front grating may be 18 μm, 20 μm, 22 μm, 24 μm or 25 μm and the width of the front grating may be 35 μm, 37 μm, 39 μm, 41 μm, 43 μm or 45 μm.
Referring to fig. 1, if the prepared PERC cell is a single-sided cell, the back surface of the cell is an aluminum back field 91, and the aluminum back field 91 is in ohmic contact with the P-type silicon substrate. Alternatively, the consumption of the aluminum paste in the formation of the aluminum back surface field 91 of the single-sided battery is between 0.8 and 0.9 g. For example: the consumption of the aluminum paste may be 0.8g, 0.82g, 0.84g, 0.86g, 0.88g, or 0.9 g. When the aluminum paste is printed, the aluminum paste enters the cell structure in S80, and the sintered aluminum back field 91 is brought into ohmic contact with the P-type silicon substrate 10.
Referring to fig. 2, if the prepared PERC cell is a double-sided cell, the back side of the cell is an aluminum gate line 92, and the aluminum gate line 92 is in ohmic contact with the P-type silicon substrate. Alternatively, the consumption of the aluminum paste in forming the aluminum grid line 92 of the double-sided battery is between 0.2 and 0.4 g. For example: the consumption of the aluminum paste may be 0.2g, 0.25g, 0.3g, 0.35g, or 0.4 g. When the aluminum paste is printed, the aluminum paste enters the trench structure in S80, and the sintered aluminum gate line 92 is brought into ohmic contact with the P-type silicon substrate 10.
The beneficial effects of the single-sided PERC cell (as shown in fig. 1) or the double-sided PERC cell (as shown in fig. 2) prepared by the above preparation method include:
(1) the two processes of depositing the back silicon dioxide layer 50 and depositing the back aluminum oxide layer 60 are all carried out in the cavity of the same ALD device, so that the compatibility of the processes is better, the ozone oxidation device is not required to be additionally arranged to form the back silicon dioxide, the cleanliness of a contact interface between the back silicon dioxide layer 50 and the back aluminum oxide layer 60 can be kept, the PID resistance performance and the conversion efficiency of the battery are improved, and the reliability of the battery is improved.
(2) And a phosphorus-doped N + + silicon layer 30 is formed between the N + emitter junction layer 20 and the P-type silicon substrate 10, so that the contact resistance between the silicon wafer and the electrode is reduced, the surface recombination is reduced, and the minority carrier lifetime is prolonged.
(3) The process has strong compatibility, and can meet the preparation requirements of both single-sided PERC batteries and double-sided PERC batteries.
Example 1
A preparation method of a single-sided PERC battery comprises the following steps:
(1) and (3) texturing: and cleaning and texturing the silicon wafer, removing a damage layer on the surface of the silicon wafer, and texturing the front side of the silicon wafer to form a pyramid textured surface with the height of 3 microns.
(2) And (3) diffusion: and placing the silicon wafer in a diffusion furnace, and diffusing for 40min at the diffusion temperature of 800 ℃ to deposit phosphorus oxychloride on the front surface of the silicon wafer and thermally diffuse to prepare a phosphorus-doped N + emitter junction with the thickness of 0.3 mu m.
(3) And heavy doping: and doping and diffusing local areas on the phosphorus-doped N + emitter junction layer in a laser doping mode, so that a phosphorus-doped N + + silicon layer is formed between the N + emitter junction layer and the P-type silicon substrate.
(4) Etching and back polishing: and removing the N-type layer corrosion on the edge and the back of the silicon wafer by a wet etching process, removing the phosphorosilicate glass on the front side, and polishing the back of the silicon wafer.
(5) And annealing: and putting the silicon wafer into an annealing furnace, introducing a certain amount of oxygen, and growing a front-side silicon dioxide layer with the thickness of 4nm at the temperature of 800 ℃.
(6) And back coating: and placing the annealed silicon wafer in a cavity of an ALD (atomic layer deposition) device, introducing ozone gas with the flow rate of 40sccm into the cavity of the ALD device, and oxidizing for 5min at the temperature of 200 ℃ to form a back silicon dioxide layer with the thickness of 3 nm. Then, under the condition of the temperature of 250 ℃, ozone gas is used as an oxygen source, and a back side alumina layer with the thickness of 4nm is continuously deposited. A backside silicon nitride layer was then deposited using a Plasma Enhanced Chemical Vapor Deposition (PECVD) process to a thickness of 150 nm.
(7) And coating the film on the front side: and forming a front silicon nitride layer with the thickness of 80nm on the front surface of the silicon wafer by adopting a Plasma Enhanced Chemical Vapor Deposition (PECVD) method.
(8) Laser grooving: and selectively etching part of the passivation layer (the back silicon dioxide layer, the back aluminum oxide layer and the back silicon nitride layer) on the back of the silicon chip by adopting laser etching, so as to open a groove or a hole on the back of the silicon chip and expose the structure of the P-type silicon substrate layer.
(9) Screen printing and sintering: and printing silver paste on the front surface of the silicon wafer and 0.85g of aluminum paste on the back surface of the silicon wafer according to the design of a screen printing plate graph by adopting a screen printing method, and sintering at high temperature to form a front electrode and an aluminum back field, wherein the front electrode is in ohmic contact with the phosphorus-doped N + + silicon layer, and the aluminum back field is in ohmic contact with the P-type silicon substrate.
Example 2
Example 2 is different from example 1 in that example 2 is not subjected to the heavy doping step of step (3) in example 1. The other step methods are the same as those of the embodiment.
Example 3
Example 3 differs from example 1 in that example 3 performs the preparation of a double-sided PERC cell. The difference lies in that:
(6) and back coating: and placing the annealed silicon wafer in a cavity of an ALD (atomic layer deposition) device, introducing ozone gas with the flow rate of 40sccm into the cavity of the ALD device, and oxidizing for 5min at the temperature of 200 ℃ to form a back silicon dioxide layer with the thickness of 3 nm. Then, under the condition of the temperature of 250 ℃, ozone gas is used as an oxygen source, and a back side alumina layer with the thickness of 4nm is continuously deposited. A backside silicon nitride layer was then deposited using Plasma Enhanced Chemical Vapor Deposition (PECVD) to a thickness of 95 nm.
(9) Screen printing and sintering: and printing silver paste on the front surface of the silicon wafer and 0.32g of aluminum paste on the back surface of the silicon wafer according to the design of a screen printing plate graph by adopting a screen printing method, and sintering at high temperature to form a front electrode and an aluminum grid line, wherein the front electrode is in ohmic contact with the phosphorus-doped N + + silicon layer, and the aluminum grid line is in ohmic contact with the P-type silicon substrate.
The other step methods are the same as those of the embodiment.
Comparative example 1
Comparative example 1 a single sided PERC cell was prepared, comparative example 1 differing from example 1 in that:
(6) and back coating: and (3) placing the annealed silicon wafer in an ozone machine for oxidation treatment to form a back silicon dioxide layer with the thickness of 3 nm. The wafer was then transferred to the ALD apparatus chamber and a 4nm thick backside aluminum oxide layer was deposited at a temperature of 400 c. A backside silicon nitride layer was then deposited using a Plasma Enhanced Chemical Vapor Deposition (PECVD) process to a thickness of 150 nm.
The other step methods are the same as those of the embodiment.
Examples of the experiments
The performance of the PERC cells obtained in examples 1 to 4 and the PERC cells provided in comparative examples 1 to 4 were measured as shown in table 1; the detection method comprises the following steps: a BERGER on-line I-V test system is selected to test the electrical performance parameters of the solar cell, such as open-circuit voltage, short-circuit current, filling factor, conversion efficiency and the like, under the conditions of 25 ℃, 1.5 AM and 1 standard sun.
TABLE 1PERC Battery Performance
Item Counting Eta(%) Uoc(V) Isc(A) Rs
Example 1 800 22.493 0.6774 10.382 0.0020
Example 2 400 22.496 0.6778 10.378 0.0020
Example 3 800 22.464 0.6767 10.375 0.0019
Comparative example 1 1200 22.396 0.6757 10.360 0.0019
As can be seen from table 1, ozone gas is introduced into the chamber of the ALD apparatus to form a back silicon oxide layer, and ozone is continuously introduced into the same apparatus to form a back aluminum oxide layer, so that the conversion efficiency, open-circuit voltage, and short-circuit current of the obtained single-sided PERC cell and the double-sided PERC cell are increased to different degrees, which indicates that the PERC cell has better performance.
The embodiments described above are some, but not all embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Claims (10)

1. A preparation method of a PERC battery comprises the steps of texturing, diffusion, etching, back polishing, annealing, back film coating and front film coating, and is characterized in that,
the back surface coating step comprises:
introducing ozone gas into the equipment with the annealed silicon wafer for oxidation treatment to form a back silicon dioxide layer on the back of the silicon wafer;
then continuing to introduce ozone into the equipment as an oxygen source, adding an aluminum source, and depositing a back aluminum oxide layer on the back silicon dioxide layer;
depositing a back side silicon nitride layer on the back side aluminum oxide layer.
2. The production method according to claim 1, wherein the conditions for introducing ozone gas into the apparatus containing the annealed silicon wafer to perform the oxidation treatment comprise: the flow rate of the ozone is 5-150sccm, the oxidation time is 1-10min, and the oxidation temperature is 150-.
3. The method as claimed in claim 2, wherein the step of depositing the back alumina layer on the back silicon dioxide layer is performed at a deposition temperature of 150 ℃ to 300 ℃.
4. A production method according to any one of claims 1 to 3, characterized in that the apparatus is an ALD apparatus.
5. The method of manufacturing according to claim 4, wherein the diffusing includes: doping phosphorus on the textured silicon wafer to form a phosphorus-doped N + emitter junction layer;
the preparation method further comprises the following steps: and carrying out doping diffusion of a local area on the phosphorus-doped N + emitter junction layer to form a phosphorus-doped N + + silicon layer between the N + emitter junction layer and the silicon wafer.
6. The method of claim 5, wherein the phosphorus-doped N + + silicon layer is formed by laser doping.
7. A single sided PERC cell, comprising:
a P-type silicon substrate;
the front surface of the P-type silicon substrate is sequentially provided with a phosphorus-doped N + emitter junction layer, a front surface silicon dioxide layer, a front surface antireflection layer and a front surface electrode, a phosphorus-doped N + + silicon layer is arranged between the phosphorus-doped N + emitter junction layer and the P-type silicon substrate, and the front surface electrode is in ohmic contact with the phosphorus-doped N + + silicon layer;
the back surface of the silicon substrate is sequentially provided with a back silicon dioxide layer, a back aluminum oxide layer, a back silicon nitride layer and an aluminum back field, and the aluminum back field is in ohmic contact with the P-type silicon substrate.
8. The single sided PERC cell of claim 7, wherein the phosphorus doped N + emitter junction layer has a thickness of 0.2-0.4 μm, and wherein the back side silicon dioxide layer and the front side silicon dioxide layer each have a thickness of 2-5 nm.
9. A double-sided PERC battery, comprising:
a P-type silicon substrate;
the front surface of the P-type silicon substrate is sequentially provided with a phosphorus-doped N + emitter junction layer, a front surface silicon dioxide layer, a front surface antireflection layer and a front surface electrode, a phosphorus-doped N + + silicon layer is arranged between the phosphorus-doped N + emitter junction layer and the P-type silicon substrate, and the front surface electrode is in ohmic contact with the phosphorus-doped N + + silicon layer;
the back surface of the silicon substrate is sequentially provided with a back silicon dioxide layer, a back aluminum oxide layer, a back silicon nitride layer and an aluminum grid line, and the aluminum grid line is in ohmic contact with the P-type silicon substrate.
10. The dual sided PERC cell of claim 9, wherein the phosphorus doped N + emitter junction layer has a thickness of 0.2-0.4 μm, and wherein the back side silicon dioxide layer and the front side silicon dioxide layer each have a thickness of 2-5 nm.
CN201911256027.6A 2019-12-09 2019-12-09 PERC battery and preparation method thereof Pending CN110854240A (en)

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111490130A (en) * 2020-04-21 2020-08-04 浙江正泰太阳能科技有限公司 Back passivation solar cell and preparation method thereof
CN112599616A (en) * 2020-12-15 2021-04-02 泰州隆基乐叶光伏科技有限公司 Solar cell and manufacturing method thereof
CN112736146A (en) * 2020-12-31 2021-04-30 湖南红太阳新能源科技有限公司 PERC battery based on point contact and composite film layer
CN112795906A (en) * 2021-01-22 2021-05-14 无锡琨圣智能装备股份有限公司 Double-layer O-ALD atomic layer deposition equipment
CN112864280A (en) * 2021-01-29 2021-05-28 通威太阳能(安徽)有限公司 High-reliability double-sided battery and preparation method thereof
CN114038945A (en) * 2021-12-06 2022-02-11 江西中弘晶能科技有限公司 Method for preparing novel PERC (Positive electrode collector) battery in single-side ALD (atomic layer deposition) mode
CN114182236A (en) * 2021-11-25 2022-03-15 晶澳太阳能有限公司 Method for detecting abnormity of aluminum oxide coating equipment
WO2022242067A1 (en) 2021-05-18 2022-11-24 横店集团东磁股份有限公司 Perc battery back passivation structure, and perc battery and preparation method therefor
EP4084087A4 (en) * 2020-12-25 2023-07-26 Tongwei Solar (Chengdu) Co., Ltd. Perc solar cell selective emitter, perc solar cell and manufacturing method therefor

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111490130A (en) * 2020-04-21 2020-08-04 浙江正泰太阳能科技有限公司 Back passivation solar cell and preparation method thereof
CN112599616A (en) * 2020-12-15 2021-04-02 泰州隆基乐叶光伏科技有限公司 Solar cell and manufacturing method thereof
EP4084087A4 (en) * 2020-12-25 2023-07-26 Tongwei Solar (Chengdu) Co., Ltd. Perc solar cell selective emitter, perc solar cell and manufacturing method therefor
CN112736146A (en) * 2020-12-31 2021-04-30 湖南红太阳新能源科技有限公司 PERC battery based on point contact and composite film layer
CN112795906A (en) * 2021-01-22 2021-05-14 无锡琨圣智能装备股份有限公司 Double-layer O-ALD atomic layer deposition equipment
CN112864280A (en) * 2021-01-29 2021-05-28 通威太阳能(安徽)有限公司 High-reliability double-sided battery and preparation method thereof
WO2022242067A1 (en) 2021-05-18 2022-11-24 横店集团东磁股份有限公司 Perc battery back passivation structure, and perc battery and preparation method therefor
CN114182236A (en) * 2021-11-25 2022-03-15 晶澳太阳能有限公司 Method for detecting abnormity of aluminum oxide coating equipment
CN114038945A (en) * 2021-12-06 2022-02-11 江西中弘晶能科技有限公司 Method for preparing novel PERC (Positive electrode collector) battery in single-side ALD (atomic layer deposition) mode

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