WO2024007874A1 - 太阳电池及其制备方法 - Google Patents

太阳电池及其制备方法 Download PDF

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Publication number
WO2024007874A1
WO2024007874A1 PCT/CN2023/102337 CN2023102337W WO2024007874A1 WO 2024007874 A1 WO2024007874 A1 WO 2024007874A1 CN 2023102337 W CN2023102337 W CN 2023102337W WO 2024007874 A1 WO2024007874 A1 WO 2024007874A1
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silicon
layer
nitride layer
silicon nitride
solar cell
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PCT/CN2023/102337
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French (fr)
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石鑫鑫
黄智�
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Tongwei Solar Meishan Co Ltd
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Tongwei Solar Meishan Co Ltd
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Priority to US18/861,672 priority Critical patent/US20250331312A1/en
Priority to EP23834648.0A priority patent/EP4503140A4/en
Priority to AU2023301894A priority patent/AU2023301894B2/en
Publication of WO2024007874A1 publication Critical patent/WO2024007874A1/zh
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F10/00—Individual photovoltaic cells, e.g. solar cells
    • H10F10/10—Individual photovoltaic cells, e.g. solar cells having potential barriers
    • H10F10/14—Photovoltaic cells having only PN homojunction potential barriers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F10/00—Individual photovoltaic cells, e.g. solar cells
    • H10F10/10—Individual photovoltaic cells, e.g. solar cells having potential barriers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F71/00—Manufacture or treatment of devices covered by this subclass
    • H10F71/121—The active layers comprising only Group IV materials
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F71/00—Manufacture or treatment of devices covered by this subclass
    • H10F71/129—Passivating
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/30—Coatings
    • H10F77/306—Coatings for devices having potential barriers
    • H10F77/311—Coatings for devices having potential barriers for photovoltaic cells
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/30—Coatings
    • H10F77/306—Coatings for devices having potential barriers
    • H10F77/311—Coatings for devices having potential barriers for photovoltaic cells
    • H10F77/315—Coatings for devices having potential barriers for photovoltaic cells the coatings being antireflective or having enhancing optical properties
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the field of photovoltaic technology, specifically, to a solar cell and a preparation method thereof.
  • photovoltaic modules are easily affected by the environment during operation, causing Potential Induced Degradation (PID).
  • PID Potential Induced Degradation
  • the main reason is that in a humid environment, water vapor in the air enters the module and causes EVA (vinyl acetate)
  • EVA vinyl acetate
  • the acetic acid produced by hydrolysis reacts with the alkali salts precipitated from the glass to generate freely mobile alkali metal ions such as Na + , Ca + , Fe 2+ , Fe 3+ , etc.
  • These ions will move to the battery sheet under the action of a certain external electric field for a long time. surface, penetrating the anti-reflective film of the cell, resulting in the loss of its passivation effect.
  • these ions will further migrate into the inside of the cell and form a built-in electric field with the holes generated by the PN junction, limiting the output of photogenerated carriers. This will eventually lead to component power attenuation and seriously affect power generation.
  • This application provides a solar cell and a preparation method thereof, which can ensure that both the front and back sides of the solar cell have good anti-reflection effects and improve the anti-PID performance of the solar cell.
  • the example of this application provides a method for preparing a solar cell, which includes: providing a semi-finished silicon wafer, and using an atomic layer deposition method to form a first silicon oxide layer and a second oxide layer on the front and back sides of the semi-finished silicon wafer respectively. silicon layer.
  • the semi-finished silicon wafer includes at least one silicon nitride layer, an aluminum oxide layer, a silicon layer, at least one silicon nitride layer, a silicon oxynitride layer and a third silicon oxide layer that are stacked in sequence along the thickness direction.
  • the first silicon oxide layer Combined with the surface of the third silicon oxide layer, the second silicon oxide layer is combined with the surface of the silicon nitride layer.
  • the solar cell preparation method of the present application can form dense silicon oxide layers on the front and back of the semi-finished silicon wafer through atomic layer deposition, thereby effectively blocking alkali metal ions from the component glass and preventing these Metal ions penetrate the film layer of the solar cell and reach the inside of the silicon wafer to destroy the PN junction and improve the anti-PID performance of the solar cell.
  • the dense silicon oxide layer formed by atomic layer deposition will not affect the anti-reflection effect on the front and back of the solar cell, maintaining high photoelectric conversion efficiency.
  • the thickness of the first silicon oxide layer and the second silicon oxide layer is 5 to 10 nm.
  • an appropriate thickness of the silicon oxide layer is not only beneficial to improving the anti-PID performance of the solar cell, but also enables the solar cell to maintain a high photoelectric conversion efficiency.
  • the above-mentioned atomic layer deposition method includes:
  • the flow rate of the silicon-based precursor is 10 ⁇ 50 sccm
  • the flow rate of the oxidant precursor is 10 ⁇ 50 sccm.
  • the reaction chamber is in a vacuum environment before the gaseous silicon-based precursor is introduced.
  • the gaseous silicon-based precursor is first introduced into the reaction chamber, and the gaseous silicon-based precursor will be chemically adsorbed on the surface of the semi-finished silicon wafer substrate, and then the gaseous oxidant precursor is introduced into the reaction chamber.
  • the gaseous oxidant precursor and The silicon-based precursor on the surface of the semi-finished silicon wafer substrate reacts to form a silicon oxide film.
  • the thickness of silicon oxide deposited in a single time is 0.1 ⁇ 0.15nm, and a silicon nitride layer of 5 ⁇ 10nm can be obtained by repeated deposition 50 ⁇ 100 times.
  • the above-mentioned silicon-based precursor includes hexachlorodisilane, bis(diethylamino)silane, tris(dimethylamino)silane and trimethylsilane Any one or more of amines, and the oxidizing agent includes at least one of oxygen and ozone.
  • the pressure in the reaction chamber is 2 to 50 mbar, and the temperature of the semi-finished silicon wafer is 150 to 400°C.
  • the gaseous silicon-based precursor after each completion of the introduction of the gaseous silicon-based precursor, the gaseous silicon-based precursor is adsorbed on the surface of the semi-finished silicon wafer, so that excess The gaseous silicon-based precursor emerges from the reaction chamber After the reaction is completed, the unreacted gaseous silicon-based precursor and gaseous oxidant precursor are discharged from the reaction chamber, and then the next deposition is performed.
  • the above-mentioned semi-finished silicon wafer is produced by the following method:
  • the coating layer on the back side includes a first silicon nitride layer, a second silicon nitride layer, a third silicon nitride layer and an aluminum oxide layer
  • the coating layer on the front side includes a fourth silicon nitride layer, a fifth silicon nitride layer, a third silicon nitride layer and an aluminum oxide layer.
  • a vapor deposition method is used to sequentially deposit an aluminum oxide layer, a third silicon nitride layer, and a second silicon nitride layer on the back of the silicon wafer. and a first silicon nitride layer.
  • the refractive index of the third silicon nitride layer is 2.2-2.3
  • the refractive index of the second silicon nitride layer is 2.09-2.15
  • the refractive index of the first silicon nitride layer is 2.00-2.06.
  • the refractive index of the coating on the back is 2.10-2.15.
  • the refractive index of the coating on the back of the solar cell produced by this application is lower, the short-wave response of the solar cell is better, and the solar cell absorbs more blue light, causing it to have higher short-circuit current and open-circuit voltage. Thereby improving the photoelectric conversion efficiency of solar cells.
  • a vapor deposition method is used to sequentially deposit a fourth silicon nitride layer, a fifth silicon nitride layer, a sixth silicon nitride layer, and a sixth silicon nitride layer on the front side of the silicon wafer.
  • silicon oxide layer, silicon oxynitride layer and third silicon oxide layer is used to sequentially deposit.
  • the fourth silicon nitride layer has a refractive index of 2.2 to 2.3
  • the fifth silicon nitride layer has a refractive index of 2.09 to 2.17
  • the sixth silicon nitride layer has a refractive index of 2.03 to 2.06, and the silicon oxynitride layer has a refractive index of 2.09 to 2.17.
  • the refractive index is 1.55 ⁇ 1.9.
  • the refractive index of the front coating is 2 to 2.05.
  • the refractive index of the coating on the front side of the solar cell produced by this application is lower, the short-wave response of the solar cell is better, and the solar cell absorbs more blue light, causing it to have higher short-circuit current and open-circuit voltage. Thereby improving the photoelectric conversion efficiency of solar cells.
  • the example of this application provides a solar cell, which is produced according to the above-mentioned solar cell preparation method.
  • the solar cell of the present application has better anti-PID performance and higher photoelectric conversion efficiency. Rate.
  • Figure 1 is a schematic structural diagram of a semi-finished silicon wafer according to an embodiment of the present application.
  • Figure 2 is a schematic structural diagram of a solar cell according to an embodiment of the present application.
  • PID attenuation on mainstream PERC battery products is mainly divided into front PID failure and back PID failure.
  • the failure mechanisms of the front and back are slightly different, and the anti-PID attenuation measures taken are also different.
  • the component side mainly uses optimized packaging materials to prevent external water vapor from entering; the battery side mainly optimizes the process, such as using thermal oxygen, ozone, etc. to grow a layer between the silicon wafer and the silicon nitride positive film.
  • a very thin silicon oxide film is used to block the migration of alkali metal ions into the silicon wafer; or a high refractive index silicon nitride layer is used to enhance the passivation effect and block free positively charged ions, and at the same time, PECVD is used to deposit low refractive index SiO x N y to reduce the overall
  • the refractive index of the body film layer increases the proportion of incident light and improves short-circuit current and photoelectric conversion efficiency. Further depositing a silicon oxide layer with a lower refractive index on the top layer can greatly improve the anti-reflection effect of the film layer and enhance the short-wave response.
  • the silicon oxide layer formed between the silicon wafer and the silicon nitride positive film through hot oxygen, ozone, etc. is very thin, about 5 to 6 ⁇ m.
  • the resistance to PID mainly relies on the silicon oxide layer between the silicon wafer and the silicon nitride positive film.
  • component materials have changed significantly, making it difficult for the silicon oxide layer between the silicon wafer and the silicon nitride positive film to resist the migration of alkali metal ions into the silicon wafer and destroying the PN junction, exacerbating the power attenuation of the module. If the thickness of silicon oxide at the bottom of the silicon wafer is increased by increasing the process time of thermal oxygen, ozone, etc., this method will have a greater impact on production capacity and will cause the photoelectric conversion efficiency of the solar cell to decrease.
  • the thickness of the outermost silicon oxide layer prepared by PECVD often reaches 25nm, accounting for about 1/3 of the total film thickness. This layer of silicon oxide is not The ability to resist PID also results in the total thickness of the remaining silicon nitride layer being insufficient and making PID failure more likely.
  • the inventor's research found that a method of depositing a silicon oxycarbide film with a larger refractive index on the bottom layer to improve passivation and anti-PID performance.
  • silicon oxide is used in the surface layer to reduce the overall refractive index and improve the anti-reflection effect
  • the oxidation film prepared by PECVD The silicon film has poor density and has a loose porous structure. Compared with silicon oxide generated by thermal oxygen, it is difficult to resist the migration of alkali metal ions.
  • the silicon carbide film has a high refractive index and a high extinction coefficient. When the film thickness is too thick, It is easy to cause extinction, and the incident light is absorbed by the positive film, causing the loss of photogenerated carriers. Therefore, when designing the anti-reflective coating for solar cell positive films from the perspective of improving anti-PID performance, it is necessary to simultaneously consider the characteristics of each film layer, and maintain good anti-reflective effects while improving anti-PID performance.
  • the present application provides a method for preparing a solar cell, which includes: providing a semi-finished silicon wafer, and using an atomic layer deposition method to form a first silicon oxide layer and a second silicon oxide layer on the front and back of the semi-finished silicon wafer respectively.
  • the thickness of the first silicon oxide layer and the second silicon oxide layer is 5 to 10 nm.
  • a suitable thickness of the silicon oxide layer will not only improve the anti-PID performance of the solar cell, but also keep the solar cell relatively stable. High photoelectric conversion efficiency.
  • the thickness of the first silicon oxide layer and the second silicon oxide layer is 8 nm. In some other embodiments of the present application, the thickness of the first silicon oxide layer and the second silicon oxide layer may also be 5 nm, 6 nm, 7 nm, 9 nm or 10 nm.
  • the thicknesses of the first silicon oxide layer and the second silicon oxide layer may be equal or different.
  • Atomic layer deposition methods include:
  • the semi-finished silicon wafer is placed in the reaction chamber, and the gaseous silicon-based precursor is first introduced into the reaction chamber under a vacuum environment.
  • the gaseous silicon-based precursor will be chemically adsorbed on the surface of the semi-finished silicon wafer substrate, and the excess gaseous silicon-based precursor will be It is discharged from the reaction chamber, and then a gaseous oxidant precursor is introduced into the reaction chamber.
  • the gaseous oxidant precursor reacts with the silicon-based precursor on the surface of the semi-finished silicon wafer substrate to generate a silicon oxide film, so that the unreacted gaseous silicon-based precursor and Gaseous oxidant precursor is discharged from the reaction chamber.
  • the thickness of the silicon oxide layer produced by controlling the number of cycles. Since the thickness of silicon oxide deposited in a single time is 0.1-0.15nm, the total number of cycles is 50-100 cycles to obtain 5-10nm. silicon nitride layer.
  • the silicon-based precursor includes any one or more of hexachlorodisilane, bis(diethylamino)silane, tris(dimethylamino)silane and trimethylsilylamine.
  • the oxidizing agent includes at least one of oxygen and ozone.
  • the introduction time of the gaseous silicon-based precursor is 2 to 5 seconds, and the flow rate of the silicon-based precursor is 10 to 50 sccm.
  • the introduction time of the gaseous silicon-based precursor is 3 seconds, and the flow rate of the silicon-based precursor is 30 sccm.
  • the introduction time of the gaseous silicon-based precursor can also be 2s, 2.5s, 3.5s, 4s, 4.5s or 5s, and the flow rate of the silicon-based precursor is 10sccm, 15sccm, 20sccm, 25sccm, 35sccm, 400sccm, 45sccm or 50sccm.
  • the introduction time of the gaseous oxidant precursor is 5 to 15 seconds, and the flow rate of the oxidant precursor is 10 to 50 sccm.
  • the introduction time of the gaseous oxidant precursor is 10 s, and the flow rate of the oxidant precursor is 30 sccm. In some other embodiments of the present application, the introduction time of the gaseous oxidant precursor can also be 5s, 6s, 7s, 8s, 9s, 11s, 12s, 13s, 14s or 15s, and the flow rate of the oxidant precursor can also be 30 sccm. .
  • the pressure in the reaction chamber is 2 ⁇ 50mbar.
  • the pressure in the reaction chamber is 20 mbar. In some other embodiments of the present application, the pressure in the reaction chamber can also be 2mbar, 5mbar, 10mbar, 15mbar, 25mbar, 30mbar, 35mbar, 40mbar, 45mbar or 50mbar.
  • the temperature of semi-finished silicon wafers is 150 ⁇ 400°C.
  • the temperature of the semi-finished silicon wafer is 250°C. In some other embodiments of the present application, the temperature of the semi-finished silicon wafer can also be 150°C, 200°C, 300°C, 350°C or 400°C.
  • Methods for removing excess gaseous silicon-based precursor and unreacted gaseous silicon-based precursor and gaseous oxidant precursor from the reaction chamber include pumping or inert gas purging.
  • the purge time of inert gas is 0.5 ⁇ 20s, and the purge flow rate is 100 ⁇ 3000sccm.
  • the atomic layer deposition method may be a plasma enhanced atomic layer deposition method.
  • the semi-finished silicon wafer includes at least one silicon nitride layer, an aluminum oxide layer, a silicon layer, at least one silicon nitride layer, a silicon oxynitride layer and a third silicon oxide layer that are stacked in sequence along the thickness direction.
  • the semi-finished silicon wafer 10 includes a first silicon nitride layer 101 , a second silicon nitride layer 102 , a third silicon nitride layer 103 , an aluminum oxide layer 104 , and a silicon layer 105 that are stacked in sequence along the thickness direction.
  • the solar cell preparation method of the present application uses atomic layer deposition to form dense silicon oxide layers on the front and back of the semi-finished silicon wafer to prepare the finished silicon wafer 20.
  • the finished silicon wafer 20 includes sequentially The stacked second silicon oxide layer 202, the first silicon nitride layer 101, the second silicon nitride layer 102, the third silicon nitride layer 103, the aluminum oxide layer 104, the silicon layer 105, and the fourth silicon nitride layer 106 , the fifth silicon nitride layer 107, the sixth silicon nitride layer 108, the silicon oxynitride layer 109, the third silicon oxide layer 110 and the first silicon oxide layer 201.
  • Semi-finished silicon wafers are produced by depositing coatings on the back and front sides of the wafer.
  • Deposition methods for the coating on the backside of the silicon wafer include:
  • a PECVD two-in-one machine is used to deposit an aluminum oxide layer on the back of the thermally oxidized silicon wafer to ensure the passivation effect on the back, and then deposit the third silicon nitride layer and the second nitride layer on the surface of the aluminum oxide layer in sequence. silicon layer and first silicon nitride layer.
  • the overall refractive index of the film layer on the back of the silicon wafer is 2.10 ⁇ 2.15, and the total thickness is 80 ⁇ 110nm.
  • the thickness of the aluminum oxide layer is 5 to 15 nm.
  • the flow rate of laughing gas is 1000 to 10000 sccm, and the flow rate of trimethylaluminum is 5 to 100 sccm.
  • the silicon wafer substrate temperature is 280 ⁇ 350°C, and the deposition time is 100 ⁇ 150s.
  • the flow rate of laughing gas is 3000-7000ccm, and the flow rate of trimethylaluminum is 30-70sccm.
  • the thickness of the third silicon nitride layer is 5 to 25 nm, and the refractive index is 2.2 to 2.3.
  • the thickness of the fourth silicon oxide layer is 10 to 20 nm, and the refractive index is 2.09 to 2.15.
  • the thickness of the fifth silicon oxide layer is 20 to 40 nm, and the refractive index is 2 to 2.06.
  • the flow rate of silane is 1 to 3000 sccm
  • the flow rate of ammonia is 1 to 20000 sccm
  • the pressure is 800 to 2000 mTor
  • the power is 600 to 2000W
  • the deposition temperature is 400 to 450°C.
  • the flow rate of silane is 1000-2000 sccm
  • the pressure is 1200-1800 mTor
  • the power is 1000-1500W.
  • the flow ratio of silane and ammonia gas is 1:4 ⁇ 1:5, and the deposition time is 50 ⁇ 200s.
  • the flow ratio of silane and ammonia is 1:7 ⁇ 1:9, and the deposition time is 100 ⁇ 200s.
  • the flow ratio of silane and ammonia is 1:10 ⁇ 1:12, and the deposition time is 200 ⁇ 400s.
  • Deposition methods for coatings on the front side of silicon wafers include:
  • a PECVD two-in-one machine is used to sequentially deposit the fourth silicon nitride layer, the fifth silicon nitride layer, the sixth silicon nitride layer, the silicon oxynitride layer and the third silicon oxide layer on the front side of the silicon wafer that has completed back-side coating.
  • the overall refractive index of the film layer on the front side of the silicon wafer is 2 to 2.05, and the total thickness is 65 to 80nm.
  • the thickness of the fourth silicon nitride layer is 5-25 nm, and the refractive index is 2.2-2.3.
  • the thickness of the fifth silicon nitride layer is 10 to 20 nm, and the refractive index is 2.09 to 2.17.
  • the thickness of the sixth silicon nitride layer is 10 to 15 nm, and the refractive index is 2.03 to 2.06.
  • the flow rate of silane is 100-3000 sccm
  • the flow rate of ammonia is 100-20000 sccm
  • the pressure is 800-2000 mTor
  • the power is 600-2000W
  • the deposition temperature is 500-600°C.
  • the flow rate of silane is 1000-1500 sccm
  • the pressure is 1200-1800 mTor
  • the power is 1000-1500W.
  • the flow ratio of silane and ammonia is 1:4 ⁇ 1:5, and the deposition time is 50 ⁇ 200s.
  • the flow ratio of silane and ammonia is 1:6 ⁇ 1:9, and the deposition time is 100 ⁇ 200s.
  • the flow ratio of silane and ammonia is 1:10 ⁇ 1:11, and the deposition time is 100 ⁇ 120s.
  • the thickness of the silicon oxynitride layer is 10 to 30 nm, and the refractive index is 1.55 to 1.90.
  • the flow rate of silane is 1 ⁇ 1000sccm
  • the flow rate of ammonia is 1 ⁇ 10000sccm
  • the flow rate of laughing gas is 1 ⁇ 10000sccm
  • the pressure is 800 ⁇ 2000mTor
  • the power is 600 ⁇ 2000W
  • the deposition temperature is 500 ⁇ 600°C.
  • the flow rate of silane is 300-1000 sccm
  • the flow rate of ammonia is 6000-10000 sccm
  • the flow rate of laughing gas is 5000-9000 sccm
  • the pressure is 1200-1800 mTor
  • the power is 1000-1500 W .
  • the thickness of the third silicon oxide layer is 10-30 nm.
  • the solar cell preparation method of the present application can form dense silicon oxide layers on the front and back of the semi-finished silicon wafer through atomic layer deposition, thereby effectively blocking alkali metal ions from the component glass and preventing these metal ions from penetrating the solar cell.
  • the film layer reaches the inside of the silicon wafer and destroys the PN junction, improving the anti-PID performance of the solar cell.
  • the dense silicon oxide layer formed by atomic layer deposition will not affect the anti-reflection effect on the front and back of the solar cell.
  • the refractive index of the coating on the back and front of the solar cell is low, and the short-wave response of the solar cell is better. Solar cells absorb more blue light, causing them to have higher short-circuit current and open-circuit voltage, thus improving the photoelectric conversion efficiency of solar cells.
  • this application provides a method for preparing solar cells, including:
  • Texturing Use monocrystalline P-type silicon wafers, and use alkali to texturize the front and back sides to form a textured pyramid light-trapping structure.
  • Laser SE Using the phosphorus silicate glass formed during the diffusion process as the phosphorus source, laser doping is performed on the front side of the diffused silicon wafer and the metallized area corresponding to the positive electrode gate line to form a heavily doped area, thereby forming a heavily doped area on the silicon wafer.
  • the front side implements a selective emitter structure, and the sheet resistance of the heavily doped region is between 80-100 ⁇ /sq.
  • Hot oxygen After laser SE, the silicon wafer is oxidized with oxygen to form an oxide layer on the front surface to protect the front PN junction from damage.
  • PSG removal Use hydrofluoric acid to remove the PSG generated on the back and periphery of the thermally oxidized silicon wafer.
  • Alkali polishing Polish the back and edge of the silicon wafer after PSG removal, and remove PSG on the front side at the same time.
  • Oxidation annealing The alkali-polished silicon wafer is oxidized and annealed to form a silicon oxide layer on the silicon surface.
  • Dense silicon oxide layers on the front and back sides Prepare a silicon oxide layer on the front and back sides of the semi-finished silicon wafer according to the aforementioned method.
  • Backside laser The corresponding backlaser pattern is used according to the backside graphic design.
  • the fine sub-grid area on the backside is laser-opened to increase contact, and the aluminum main grid and back electrode area are not lasered.
  • S16. Sintering co-sinter the silicon wafer with the front electrode printed on it.
  • steps S8 and S9 can be exchanged, that is, the passivation film can be deposited on the back and the anti-reflective film can be deposited on the front.
  • the steps of depositing the anti-reflective film on the front are performed first, and then the passivation is deposited on the back. membrane steps.
  • This application also provides a solar cell, which is produced according to the above-mentioned solar cell preparation method.
  • the solar cell of the present application has better anti-PID performance and higher photoelectric conversion efficiency.
  • the embodiment of the present application provides a solar cell and a preparation method thereof, which includes the following steps:
  • Texturing Use monocrystalline P-type silicon wafers, and use alkali to texturize the front and back sides to form a textured pyramid light-trapping structure.
  • Laser SE Using the phosphorus silicate glass formed during the diffusion process as the phosphorus source, laser doping is performed on the front side of the diffused silicon wafer and the metallized area corresponding to the positive electrode gate line to form a heavily doped area, thereby forming a heavily doped area on the silicon wafer.
  • the front side implements the structure of selective emitter, The sheet resistance of the heavily doped region is between 90 ⁇ /sq.
  • Hot oxygen After laser SE, the silicon wafer is oxidized with oxygen to form an oxide layer on the front surface to protect the front PN junction from damage.
  • PSG removal Use hydrofluoric acid to remove the PSG generated on the back and periphery of the thermally oxidized silicon wafer.
  • Alkali polishing Polish the back and edge of the silicon wafer after PSG removal, and remove PSG on the front side at the same time.
  • Oxidation annealing The alkali-polished silicon wafer is oxidized and annealed to form a silicon oxide layer on the silicon surface.
  • the ammonia gas flow rate is 4800 sccm, and the deposition is 120 seconds to prepare the fourth silicon nitride layer with a thickness of 15 nm and a refractive index of 2.3; the silane flow rate is 1200 sccm, the ammonia gas flow rate is 8400 sccm, and the deposition is 100 seconds to prepare a fifth nitrogen layer with a thickness of 10 nm and a refractive index of 2.15.
  • Silicon nitride layer feed the alkane flow rate 1200sccm, the ammonia flow rate 12000sccm, and deposit for 120s to obtain the fifth silicon nitride layer with a thickness of 15nm and a refractive index of 2.06; then feed the silane flow rate 800sccm, the nitrogen flow rate 7000sccm, and the laughing gas flow 5000sccm.
  • the process of depositing the first silicon oxide layer and the second silicon oxide layer on the front and back of the semi-finished silicon wafer using the ALD atomic layer deposition method includes: placing the semi-finished silicon wafer in a reaction chamber, In a vacuum environment, 25 sccm of hexachlorodisilane is first introduced into the reaction chamber for 4 seconds. The hexachlorodisilane will be chemically adsorbed on the surface of the semi-finished silicon wafer substrate, causing the excess hexachlorodisilane to be discharged from the reaction chamber, and then to 25 sccm of ozone is introduced into the reaction chamber for 10 seconds.
  • Ozone reacts with hexachlorodisilane on the surface of the semi-finished silicon wafer substrate to form a silicon oxide film, causing unreacted hexachlorodisilane and ozone to react. It is discharged from the reaction chamber; the pressure in the reaction chamber is 25 mbar, and the temperature of the semi-finished silicon wafer is 300°C; the above steps are repeated 50 times to prepare a first silicon oxide layer and a second silicon oxide layer with a thickness of 5 nm.
  • Backside laser The corresponding backlaser pattern is used according to the backside graphic design.
  • the fine sub-grid area on the backside is laser-opened to increase contact, and the aluminum main grid and back electrode area are not lasered.
  • the embodiment of the present application provides a solar cell and a preparation method thereof, which includes the following steps:
  • Texturing Use monocrystalline P-type silicon wafers, and use alkali to texturize the front and back sides to form a textured pyramid light-trapping structure.
  • Laser SE Using the phosphorus silicate glass formed during the diffusion process as the phosphorus source, laser doping is performed on the front side of the diffused silicon wafer and the metallized area corresponding to the positive electrode gate line to form a heavily doped area, thereby forming a heavily doped area on the silicon wafer.
  • the front side implements a selective emitter structure, and the sheet resistance of the heavily doped region is between 90 ⁇ /sq.
  • Hot oxygen After laser SE, the silicon wafer is oxidized with oxygen to form an oxide layer on the front surface to protect the front PN junction from damage.
  • PSG removal Use hydrofluoric acid to remove the PSG generated on the back and periphery of the thermally oxidized silicon wafer.
  • Alkali polishing Polish the back and edge of the silicon wafer after PSG removal, and remove PSG on the front side at the same time.
  • Oxidation annealing The alkali-polished silicon wafer is oxidized and annealed to form a silicon oxide layer on the silicon surface.
  • the ammonia gas flow rate is 4800 sccm, and the deposition is 120 seconds to prepare the fourth silicon nitride layer with a thickness of 15 nm and a refractive index of 2.3; the silane flow rate is 1200 sccm, the ammonia gas flow rate is 8400 sccm, and the deposition is 100 seconds to prepare a fifth nitrogen layer with a thickness of 10 nm and a refractive index of 2.15.
  • Silicon nitride layer feed the alkane flow rate 1200sccm, the ammonia flow rate 12000sccm, and deposit for 120s to obtain the fifth silicon nitride layer with a thickness of 15nm and a refractive index of 2.06; then feed the silane flow rate 800sccm, the nitrogen flow rate 7000sccm, and the laughing gas flow 5000sccm.
  • the process of depositing the first silicon oxide layer and the second silicon oxide layer on the front and back of the semi-finished silicon wafer using the ALD atomic layer deposition method includes: placing the semi-finished silicon wafer in a reaction chamber, In a vacuum environment, 25 sccm of hexachlorodisilane is first introduced into the reaction chamber for 4 seconds. The hexachlorodisilane will be chemically adsorbed on the surface of the semi-finished silicon wafer substrate, causing the excess hexachlorodisilane to be discharged from the reaction chamber, and then to 25 sccm of ozone is introduced into the reaction chamber for 10 seconds.
  • Ozone reacts with hexachlorodisilane on the surface of the semi-finished silicon wafer substrate to form a silicon oxide film, so that unreacted hexachlorodisilane and ozone are discharged from the reaction chamber; the pressure in the reaction chamber is 25mbar, the temperature of the semi-finished silicon wafer is 300°C; the above steps are repeated 100 times to prepare a first silicon oxide layer and a second silicon oxide layer with a thickness of 10nm.
  • Backside laser The corresponding backlaser pattern is used according to the backside graphic design.
  • the fine sub-grid area on the backside is laser-opened to increase contact, and the aluminum main grid and back electrode area are not lasered.
  • the embodiment of the present application provides a solar cell and a preparation method thereof, which includes the following steps:
  • Texturing Use monocrystalline P-type silicon wafers, and use alkali to texturize the front and back sides to form a textured pyramid light-trapping structure.
  • Laser SE Using the phosphorus silicate glass formed during the diffusion process as the phosphorus source, laser doping is performed on the front side of the diffused silicon wafer and the metallized area corresponding to the positive electrode gate line to form a heavily doped area, thereby forming a heavily doped area on the silicon wafer.
  • the front side implements a selective emitter structure, and the sheet resistance of the heavily doped region is between 90 ⁇ /sq.
  • Hot oxygen After laser SE, the silicon wafer is oxidized with oxygen to form an oxide layer on the front surface to protect the front PN junction from damage.
  • PSG removal Use hydrofluoric acid to remove the PSG generated on the back and periphery of the thermally oxidized silicon wafer.
  • Alkali polishing Polish the back and edge of the silicon wafer after PSG removal, and remove PSG on the front side at the same time.
  • Oxidation annealing The alkali-polished silicon wafer is oxidized and annealed to form a silicon oxide layer on the silicon surface.
  • the ammonia gas flow rate is 4800 sccm, and the deposition is 120 seconds to prepare the fourth silicon nitride layer with a thickness of 15 nm and a refractive index of 2.3; the silane flow rate is 1200 sccm, the ammonia gas flow rate is 8400 sccm, and the deposition is 220 seconds to prepare a fifth nitrogen layer with a thickness of 20 nm and a refractive index of 2.15.
  • Silicon nitride layer Silicon nitride layer; the alkane flow rate is 1200sccm, the ammonia flow rate is 12000sccm, and the deposition is 350s to obtain a 35nm thick silicon nitride layer with a refractive index of 2.06; the overall refractive index of the film layer on the front of the silicon wafer is 2.15, and the total thickness is 70nm.
  • Backside laser The corresponding backlaser pattern is used according to the backside graphic design. The fine sub-grid area on the backside is laser-opened to increase contact, and the aluminum main grid and back electrode area are not lasered.
  • Back electrode preparation Screen printing is used, and silver paste is used to print the back silver electrode and PAD dots on the silicon wafer after back laser grooving.
  • the embodiment of the present application provides a solar cell and a preparation method thereof, which includes the following steps:
  • Texturing Use monocrystalline P-type silicon wafers, and use alkali to texturize the front and back sides to form a textured pyramid light-trapping structure.
  • Laser SE Using the phosphorus silicate glass formed during the diffusion process as the phosphorus source, laser doping is performed on the front side of the diffused silicon wafer and the metallized area corresponding to the positive electrode gate line to form a heavily doped area.
  • the front side implements a selective emitter structure, and the sheet resistance of the heavily doped region is between 90 ⁇ /sq.
  • Hot oxygen After laser SE, the silicon wafer is oxidized with oxygen to form an oxide layer on the front surface to protect the front PN junction from damage.
  • PSG removal Use hydrofluoric acid to remove the PSG generated on the back and periphery of the thermally oxidized silicon wafer.
  • Alkali polishing Polish the back and edge of the silicon wafer after PSG removal, and remove PSG on the front side at the same time.
  • Oxidation annealing The alkali-polished silicon wafer is oxidized and annealed to form a silicon oxide layer on the silicon surface.
  • the ammonia gas flow rate is 4800 sccm, and the fourth silicon nitride layer with a thickness of 15 nm and a refractive index of 2.3 is obtained by depositing for 120 seconds; the silane flow rate is 1200 sccm, the ammonia gas flow rate is 8400 sccm, and the fifth nitrogen layer with a thickness of 10 nm and a refractive index of 2.15 is obtained by deposition for 100 seconds.
  • Silicon nitride layer feed the alkane flow rate 1200sccm, the ammonia flow rate 12000sccm, and deposit for 120s to obtain the fifth silicon nitride layer with a thickness of 15nm and a refractive index of 2.06; then feed the silane flow rate 800sccm, the nitrogen flow rate 7000sccm, and the laughing gas flow 5000sccm.
  • Non-dense silicon oxide layer on the front and back Use a PECVD two-in-one machine to form layers on the front and back of the semi-finished silicon wafer.
  • the process of depositing the first silicon oxide layer and the second silicon oxide layer includes: maintaining the temperature of the silicon wafer substrate at 530°C, introducing a silane flow rate of 600 sccm, an ammonia gas flow rate of 12,000 sccm, and depositing for 180 seconds to obtain a first layer with a thickness of 15 nm and a refractive index of 1.45. silicon oxide layer and a second silicon oxide layer.
  • Backside laser The corresponding backlaser pattern is used according to the backside graphic design.
  • the fine sub-grid area on the backside is laser-opened to increase contact, and the aluminum main grid and back electrode area are not lasered.
  • Comparative Example 2 has a great improvement;
  • Example 1 is based on Comparative Example 2, 5nm thick dense silicon oxide is prepared by ALD on both the front and back sides, and the anti-PID performance is greatly improved;
  • Example 2 further increases the thickness of dense silicon oxide, and PID The attenuation value further decreased;
  • Comparative Example 1 is based on Example 1 without the step of dense silicon oxide layer on the front and back, and the PID attenuation value increased.
  • the front-side PID 96H attenuation of the solar cell produced in the embodiment of the present application is ⁇ 1%, and the 192H attenuation is ⁇ 2%.

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Abstract

提供一种太阳电池及其制备方法，属于光伏技术领域。太阳电池的制备方法包括：提供半成品硅片，采用原子层沉积法在半成品硅片的正面和背面分别形成第一氧化硅层和第二氧化硅层。半成品硅片沿厚度方向包括依次层叠布置的至少一层氮化硅层、氧化铝层、硅层、至少一层氮化硅层、氮氧化硅层和第三氧化硅层，第一氧化硅层结合于第三氧化硅层表面，第二氧化硅层结合于氮化硅层表面。制备方法通过原子层沉积法能够在半成品硅片的正面和背面分别形成致密的氧化硅层，从而有效阻挡来自组件玻璃中的碱金属离子，防止这些金属离子透过太阳电池的膜层达到硅片内部而破坏PN结，提升太阳电池的抗PID性能。

Description

太阳电池及其制备方法
本申请要求于2022年07月08日提交中国专利局、申请号为202210804635.1、申请名称为“一种太阳电池及其制备方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及光伏技术领域，具体而言，涉及一种太阳电池及其制备方法。
背景技术
光伏组件作为光伏发电的基本单元，在运行过程中受环境影响容易导致电势诱导衰减(Potential Induced Degradation,PID)，其主要原因是在潮湿环境下空气中的水汽进入组件使得EVA(醋酸乙烯酯)水解产生的醋酸与玻璃析出的碱盐反应生成可以自由移动的Na+、Ca+、Fe2+、Fe3+等碱金属离子，这些离子会在长时间受到一定外加电场作用下移动至电池片表面，穿透电池片的减反射膜，导致其钝化效果丧失。同时，这些离子会进一步迁移至电池片内部，与PN结产生的空穴形成内建电场，限制光生载流子的输出，最终导致组件功率衰减，严重影响发电量。
发明内容
本申请提供了一种太阳电池及其制备方法，其能够保证太阳电池的正面和背面均具有较好的减反射效果，并且提升太阳电池的抗PID性能。
本申请的实施例是这样实现的：
在第一方面，本申请示例提供了一种太阳电池的制备方法，其包括：提供半成品硅片，采用原子层沉积法在半成品硅片的正面和背面分别形成第一氧化硅层和第二氧化硅层。
半成品硅片沿厚度方向包括依次层叠布置的至少一层氮化硅层、氧化铝层、硅层、至少一层氮化硅层、氮氧化硅层和第三氧化硅层，第一氧化硅层结合于第三氧化硅层表面，第二氧化硅层结合于氮化硅层表面。
在上述技术方案中，本申请的太阳电池的制备方法通过原子层沉积法能够在半成品硅片的正面和背面分别形成致密的氧化硅层，从而有效阻挡来自组件玻璃中的碱金属离子，防止这些金属离子透过太阳电池的膜层达到硅片内部而破坏PN结，提升太阳电池的抗PID性能。同时，通过原子层沉积法形成的致密氧化硅层不会影响到太阳电池的正面和背面的减反射效果，保持较高的光电转换效率。
结合第一方面，在本申请的第一方面的第一种可能的示例中，上述第一氧化硅层和第二氧化硅层的厚度为5～10nm。
在上述示例中，合适的氧化硅层厚度既有利于提升太阳电池的抗PID性能，还能够使得太阳电池保持较高的光电转换效率。
结合第一方面，在本申请的第一方面的第二种可能的示例中，上述原子层沉积法包括：
将半成品硅片设置于反应室中，向反应室中通入2～5s的气态硅基前驱体，然后向反应室中通入5～15s的气态氧化剂前驱体，硅基前驱体的流量为10～50sccm，氧化剂前驱体的流量为10～50sccm。
重复上述步骤50～100次。
可选地，反应室在通入气态硅基前驱体前为真空环境。
在上述示例中，先向反应室中通入气态硅基前驱体，气态硅基前驱体会化学吸附在半成品硅片衬底表面，再向反应室中通入气态氧化剂前驱体，气态氧化剂前驱体和半成品硅片衬底表面的硅基前驱体反应生成氧化硅薄膜。单次沉积的氧化硅厚度为0.1～0.15nm，重复沉积50～100次可以获得5～10nm的氮化硅层。
结合第一方面，在本申请的第一方面的第三种可能的示例中，上述硅基前驱体包括六氯乙硅烷、双(二乙氨基)硅烷、三(二甲氨基)硅烷和三甲硅烷基胺中的任意一种或多种，氧化剂包括氧气和臭氧中的至少一种。
结合第一方面，在本申请的第一方面的第四种可能的示例中，上述反应室内压力为2～50mbar，半成品硅片的温度为150～400℃。
结合第一方面，在本申请的第一方面的第五种可能的示例中，在每次完成气态硅基前驱体的通入后，气态硅基前驱体吸附在半成品硅片表面，使过剩的气态硅基前驱体从反应室中 排出，再向反应室中通入气态氧化剂前驱体，完成反应后，使未反应的气态硅基前驱体和气态氧化剂前驱体从反应室中排出，再进行下一次的沉积。
结合第一方面，在本申请的第一方面的第六种可能的示例中，上述半成品硅片通过以下方法制得：
分别在硅片的背面和正面沉积镀层；
其中，背面的镀层包括第一氮化硅层、第二氮化硅层、第三氮化硅层和氧化铝层，正面的镀层包括第四氮化硅层、第五氮化硅层、第六氮化硅层、氮氧化硅层和第三氧化硅层。
结合第一方面，在本申请的第一方面的第七种可能的示例中，采用气相沉积法在硅片的背面依次沉积得到氧化铝层、第三氮化硅层、第二氮化硅层和第一氮化硅层。
可选地，第三氮化硅层的折射率为2.2～2.3，第二氮化硅层的折射率为2.09～2.15，第一氮化硅层的折射率为2.00～2.06。
可选地，背面的镀层的折射率为2.10～2.15。
在上述示例中，本申请制得的太阳电池的背面的镀层的折射率较低，太阳电池的短波响应较好，太阳电池吸收的蓝光较多，使其具有较高的短路电流和开路电压，从而提升太阳电池的光电转换效率。
结合第一方面，在本申请的第一方面的第八种可能的示例中，采用气相沉积法在硅片的正面依次沉积得到第四氮化硅层、第五氮化硅层、第六氮化硅层、氮氧化硅层和第三氧化硅层。
可选地，第四氮化硅层的折射率为2.2～2.3，第五氮化硅层的折射率为2.09～2.17，第六氮化硅层的折射率为2.03～2.06，氮氧化硅层的折射率为1.55～1.9。
可选地，正面的镀层的折射率为2～2.05。
在上述示例中，本申请制得的太阳电池的正面的镀层的折射率较低，太阳电池的短波响应较好，太阳电池吸收的蓝光较多，使其具有较高的短路电流和开路电压，从而提升太阳电池的光电转换效率。
在第二方面，本申请示例提供了一种太阳电池，其根据上述的太阳电池的制备方法制得。
在上述技术方案中，本申请的太阳电池具有较好的抗PID性能，以及较高的光电转换效 率。
附图说明
为了更清楚地说明本申请的技术方案，下面将对本申请中所使用的附图作简单介绍。显而易见地，下面所描述的附图仅仅是本申请的一些实施方式，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1为本申请实施例的半成品硅片的结构示意图；
图2为本申请实施例的太阳电池的结构示意图。
附图说明：10-半成品硅片；101-第一氮化硅层；102-第二氮化硅层；103-第三氮化硅层；104-氧化铝层；105-硅层；106-第四氮化硅层；107-第五氮化硅层；108-第六氮化硅层；109-氮氧化硅层；110-第三氧化硅层；20-硅片成品；201-第一氧化硅层；202-第二氧化硅层。
具体实施方式
为了便于理解本申请，下面将参照相关附图对本申请进行更全面的描述。附图中给出了本申请的较佳实施例。但是，本申请可以以许多不同的形式来实现，并不限于本文所描述的实施例。相反地，提供这些实施例的目的是使对本申请的公开内容的理解更加透彻全面。
除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同。本文中在本申请的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请。本文所使用的术语“和/或”包括一个或多个相关的所列项目的任意的和所有的组合。
在目前行业内，主流PERC电池产品上PID衰减主要分为正面PID失效和背面PID失效，正背面的失效机理略有差异，所采取的抗PID衰减措施也不相同。
关于如何缓解正面PID衰减问题，组件端主要采用优化封装材料，防止外界水汽进入；电池端主要是进行工艺优化，如通过热氧、臭氧等方式在硅片与氮化硅正膜之间生长一层很薄的氧化硅膜来阻挡碱金属离子向硅片内部迁移；或是采用高折射率的氮化硅层来增强钝化效果和阻挡游离的带正电荷离子，同时在顶层采用PECVD沉积低折射率的SiOxNy来降低整 体膜层的折射率，增加入射光比例，提升短路电流和光电转换效率。进一步在顶层沉积折射率更低的氧化硅层可以极大提高膜层的减反射效果，增强短波响应。
对于通过热氧、臭氧等方式在硅片与氮化硅正膜之间形成的氧化硅层很薄，约5～6μm。在此结构下，抗PID主要靠硅片与氮化硅正膜之间的氧化硅层。在组件降本趋势的推动下，组件物料的大幅度变动，造成硅片与氮化硅正膜之间的氧化硅层难以抵挡碱金属离子向硅片内部迁移破坏PN结，加剧组件功率衰减。如果通过增加热氧、臭氧等方式工艺时长来提升硅片底部氧化硅厚度，此方式对产能影响较大，且会造成太阳电池的光电转换效率下降。
且为了最大程度的提升正面膜层的减反效果，增加短波响应，最外层通过PECVD制备的氧化硅层的厚度往往达到了25nm，约占总膜厚的1/3，这层氧化硅不具备抗PID的能力，还导致其余的氮化硅层总厚度不够而更容易PID失效。
基于目前二合一的PECVD镀膜设备，直接将硅烷和含氧气体一起沉积在正面氮化硅顶层可以得到减反射效果较好的复合膜层，这种方式虽然在光电转换效率上和制造成本上有很大优势，但由于整体膜层的折射率偏低，在正面抗PID上存在劣势。如果正面膜层仅采用折射率高的氮化硅层，整体折射率可以高达2.12～2.15，正面抗PID性能得到明显提升，但电池片的短波吸收会遭到损失，光电转换效率下降0.1～0.15％。
发明人研究发现，在底层沉积折射率较大的碳氧化硅薄膜来提升钝化和抗PID性能的方法，虽然表层使用了氧化硅来降低整体折射率提升减反射效果，但通过PECVD制备的氧化硅薄膜的致密性很差，为疏松多孔结构，与通过热氧生成的氧化硅相比难以抵挡碱金属离子的迁移；碳化硅薄膜作为底层折射率高，消光系数也高，膜厚太厚时容易导致消光，入射光被正膜吸收造成光生载流子损失。所以从提升抗PID性能的角度来设计太阳电池正膜减反射膜需要同步考虑各膜层的特点，在提升抗PID性能的同时还要保持良好的减反射效果。
以下针对本申请实施例的一种太阳电池及其制备方法进行具体说明：
本申请提供一种太阳电池的制备方法，其包括：提供半成品硅片，采用原子层沉积法在半成品硅片的正面和背面分别形成第一氧化硅层和第二氧化硅层。
第一氧化硅层和第二氧化硅层的厚度为5～10nm。
合适的氧化硅层厚度既有利于提升太阳电池的抗PID性能，还能够使得太阳电池保持较 高的光电转换效率。
在本申请的一种实施方式中，第一氧化硅层和第二氧化硅层的厚度为8nm。在本申请的其他一些实施方式一种，第一氧化硅层和第二氧化硅层的厚度还可以为5nm、6nm、7nm、9nm或10nm。
需要说明的是，第一氧化硅层和第二氧化硅层的厚度可以相等或不等。
原子层沉积法包括：
将半成品硅片设置于反应室中，在真空环境下先向反应室中通入气态硅基前驱体，气态硅基前驱体会化学吸附在半成品硅片衬底表面，使过剩的气态硅基前驱体从反应室中排出，然后向反应室中通入气态氧化剂前驱体，气态氧化剂前驱体和半成品硅片衬底表面的硅基前驱体反应生成氧化硅薄膜，使未反应的气态硅基前驱体和气态氧化剂前驱体从反应室中排出。
重复上述步骤，通过控制循环圈数来控制制得的氧化硅层的厚度，由于单次的沉积的氧化硅厚度为0.1～0.15nm，总循环圈数为50～100圈可以获得5～10nm的氮化硅层。
硅基前驱体包括六氯乙硅烷、双(二乙氨基)硅烷、三(二甲氨基)硅烷和三甲硅烷基胺中的任意一种或多种。
氧化剂包括氧气和臭氧中的至少一种。
气态硅基前驱体的通入时间为2～5s，硅基前驱体的流量为10～50sccm。
在本申请的一种实施方式中，气态硅基前驱体的通入时间为3s，硅基前驱体的流量为30sccm。在本申请的其他一些实施方式中，气态硅基前驱体的通入时间还可以为2s、2.5s、3.5s、4s、4.5s或5s，硅基前驱体的流量为10sccm、15sccm、20sccm、25sccm、35sccm、400sccm、45sccm或50sccm。
气态氧化剂前驱体的通入时间为5～15s，氧化剂前驱体的流量为10～50sccm。
在本申请的一种实施方式中，气态氧化剂前驱体的通入时间为10s，氧化剂前驱体的流量为30sccm。在本申请的其他一些实施方式中，气态氧化剂前驱体的通入时间还可以为5s、6s、7s、8s、9s、11s、12s、13s、14s或15s，氧化剂前驱体的流量还可以为30sccm。
反应室内压力为2～50mbar。
在本申请的一种实施方式中，反应室内压力为20mbar。在本申请的其他一些实施方式中， 反应室内压力还可以为2mbar、5mbar、10mbar、15mbar、25mbar、30mbar、35mbar、40mbar、45mbar或50mbar。
半成品硅片的温度为150～400℃。
在本申请的一种实施方式中，半成品硅片的温度为250℃。在本申请的其他一些实施方式中，半成品硅片的温度还可以为150℃、200℃、300℃、350℃或400℃。
使过剩的气态硅基前驱体从反应室中排出和使未反应的气态硅基前驱体和气态氧化剂前驱体从反应室中排出的方法包括泵抽或惰性气体吹扫。
当使用惰性气体吹扫时，惰性气体的吹扫时间为0.5～20s，吹扫流量为100～3000sccm。
原子层沉积法可以为等离子体增强原子层沉积法。
其中，半成品硅片沿厚度方向包括依次层叠布置的至少一层氮化硅层、氧化铝层、硅层、至少一层氮化硅层、氮氧化硅层和第三氧化硅层。
请参阅图1，半成品硅片10沿厚度方向包括依次层叠布置的第一氮化硅层101、第二氮化硅层102、第三氮化硅层103、氧化铝层104、硅层105、第四氮化硅层106、第五氮化硅层107、第六氮化硅层108、氮氧化硅层109和第三氧化硅层110。
请参阅图2，本申请的太阳电池的制备方法通过原子层沉积法在半成品硅片的正面和背面分别形成致密的氧化硅层，制得成品硅片20，成品硅片20沿厚度方向包括依次层叠布置的第二氧化硅层202、第一氮化硅层101、第二氮化硅层102、第三氮化硅层103、氧化铝层104、硅层105、第四氮化硅层106、第五氮化硅层107、第六氮化硅层108、氮氧化硅层109、第三氧化硅层110和第一氧化硅层201。
半成品硅片通过分别在硅片的背面和正面沉积镀层制得。
硅片的背面的镀层的沉积方法包括：
采用PECVD二合一机台在热氧后的硅片背面先沉积得到氧化铝层来保证对背面的钝化效果，然后在氧化铝层表面依次沉积得到第三氮化硅层、第二氮化硅层和第一氮化硅层。
硅片背面的膜层整体折射率为2.10～2.15，总厚度80～110nm。
其中，氧化铝层的厚度为5～15nm。
在沉积氧化铝层的过程中，笑气的流量为1000～10000sccm，三甲基铝的流量为5～100sccm， 硅片基体温度为280～350℃，沉积时间为100～150s。
可选地，在沉积氧化铝层的过程中，笑气的流量为3000～7000ccm，三甲基铝的流量为30～70sccm。
第三氮化硅层的厚度为5～25nm，折射率为2.2～2.3。
第四氧化硅层的厚度为10～20nm，折射率为2.09～2.15。
第五氧化硅层的厚度为20～40nm，折射率为2～2.06。
在硅片的背面沉积氮化硅层的过程中，硅烷的流量为1～3000sccm，氨气的流量为1～20000sccm，压力为800～2000mTor，功率600～2000W，沉积温度为400～450℃。
可选地，在硅片的背面沉积氮化硅层的过程中，硅烷的流量为1000～2000sccm，压力为1200～1800mTor，功率1000～1500W。
在沉积第三氮化硅层的过程中，硅烷和氨气的流量比1:4～1:5，沉积时间为50～200s。
在沉积第四氮化硅层的过程中，硅烷和氨气的流量比为1:7～1:9，沉积时间为100～200s。
在沉积第五氮化硅层的过程中，硅烷和氨气的流量比为1:10～1:12，沉积时间为200～400s。
硅片的正面的镀层的沉积方法包括：
采用PECVD二合一机台在完成背面镀层的硅片正面依次沉积得到第四氮化硅层、第五氮化硅层、第六氮化硅层、氮氧化硅层和第三氧化硅层。
硅片正面的膜层的整体折射率为2～2.05，总厚度为65～80nm。
其中，第四氮化硅层的厚度为5～25nm，折射率为2.2～2.3。
第五氮化硅层的厚度为10～20nm，折射率为2.09～2.17。
第六氮化硅层的厚度为10～15nm，折射率为2.03～2.06。
在硅片的正面沉积氮化硅层的过程中，硅烷的流量为100～3000sccm，氨气的流量为100～20000sccm，压力为800～2000mTor，功率600～2000W，沉积温度为500～600℃。
可选地，在硅片的正面沉积氮化硅层的过程中，硅烷的流量为1000～1500sccm，压力为1200～1800mTor，功率1000～1500W。
在沉积第四氮化硅层的过程中，硅烷和氨气的流量比为1:4～1:5，沉积时间为50～200s。
在沉积第五氮化硅层的过程中，硅烷和氨气的流量比为1:6～1:9，沉积时间为100～200s。
在沉积第六氮化硅层的过程中，硅烷和氨气的流量比为1:10～1:11，沉积时间为100～120s。
氮氧化硅层的厚度为10～30nm，折射率为1.55～1.90。
在沉积氮氧化硅层的过程中，硅烷的流量为1～1000sccm，氨气的流量为1～10000sccm，笑气的流量为1～10000sccm，压力为800～2000mTor，功率600～2000W，沉积温度为500～600℃。
可选地，在沉积氮氧化硅层的过程中，硅烷的流量为300～1000sccm，氨气的流量为6000～10000sccm，笑气的流量为5000～9000sccm，压力为1200～1800mTor，功率1000～1500W。
第三氧化硅层的厚度为10～30nm。
本申请的太阳电池的制备方法通过原子层沉积法能够在半成品硅片的正面和背面分别形成致密的氧化硅层，从而有效阻挡来自组件玻璃中的碱金属离子，防止这些金属离子透过太阳电池的膜层达到硅片内部而破坏PN结，提升太阳电池的抗PID性能。同时，通过原子层沉积法形成的致密氧化硅层不会影响到太阳电池的正面和背面的减反射效果，太阳电池的背面和正面的镀层的折射率较低，太阳电池的短波响应较好，太阳电池吸收的蓝光较多，使其具有较高的短路电流和开路电压，从而提升太阳电池的光电转换效率。
以单晶P型硅片为例，本申请提供一种太阳电池的制备方法，包括：
S1、制绒：采用单晶P型硅片，用碱进行正面和背面制绒形成绒面金字塔陷光结构。
S2、扩散：将制绒后硅片，用三氯氧磷和硅片在高温下进行反应，使正面扩散形成PN发射结。扩散后正表面薄层的方块电阻为150-190Ω/sq之间。
S3、激光SE：利用扩散过程中形成的磷硅玻璃为磷源，在扩散后硅片的正面且对应正电极栅线的金属化区域进行激光掺杂，形成重掺杂区，从而在硅片正面实现选择发射极的结构，重掺杂区的方块电阻为80-100Ω/sq之间。
S4、热氧：将激光SE后硅片通氧进行氧化，在正表面形成氧化层，保护正面PN结不被破坏。
S5、去PSG：将热氧化后的硅片，用氢氟酸去除背面及周边产生的PSG。
S6、碱抛：将去PSG后的硅片进行背面和边缘抛光，同时去除正面PSG。
S7、氧化退火：将碱抛后的硅片进行氧化及退火处理，在硅表面形成氧化硅层。
S8、在背面沉积钝化膜：按照前述方法在退火后的硅片背面制备镀层。
S9、在正面沉积减反膜：按照前述方法在硅片正面制备镀层制得半成品硅片。
S10、正背面致密氧化硅层：按照前述方法在半成品硅片正背面分别制备一层氧化硅层。
S11、背面激光：根据背面图形设计采用对应的背激光图形，其中背面细副栅区域进行激光开孔增加接触，铝主栅和背电极区域不打激光。
S12、背面电极制备：采用丝网印刷方式，在背激光开槽后的硅片上，选用银浆，印刷背银电极和PAD点。
S13、背面电场制备：选用铝浆，通过丝网印刷方式同步印刷铝主栅和铝副栅。
S14、正电极主栅区印刷：采用正银浆料，在印刷了背面电极的硅片上丝网印刷制备正面电极。
S15、正面副栅区印刷：按照网板图形，采用正银浆料印刷正面副栅。
S16、烧结：将印刷正面电极的硅片进行共烧结。
S17、电注入：将烧结后的电池片进行电注入处理。
S18、成品：将产品电池片测试、分选、包装入库。
需要说明的是，步骤S8和S9的顺序可以交换，即可以在背面沉积钝化膜和在正面沉积减反膜的顺序，先进行在正面沉积减反膜的步骤，再进行在背面沉积钝化膜的步骤。
本申请还提供一种太阳电池，其根据上述的太阳电池的制备方法制得。
在上述技术方案中，本申请的太阳电池具有较好的抗PID性能，以及较高的光电转换效率。
以下结合实施例对本申请的一种太阳电池及其制备方法作进一步的详细描述。
实施例1
本申请实施例提供一种太阳电池及其制备方法，其包括以下步骤：
S1、制绒：采用单晶P型硅片，用碱进行正面和背面制绒形成绒面金字塔陷光结构。
S2、扩散：将制绒后硅片，用三氯氧磷和硅片在高温下进行反应，使正面扩散形成PN发射结。扩散后正表面薄层的方块电阻为165Ω/sq之间。
S3、激光SE：利用扩散过程中形成的磷硅玻璃为磷源，在扩散后硅片的正面且对应正电极栅线的金属化区域进行激光掺杂，形成重掺杂区，从而在硅片正面实现选择发射极的结构， 重掺杂区的方块电阻为90Ω/sq之间。
S4、热氧：将激光SE后硅片通氧进行氧化，在正表面形成氧化层，保护正面PN结不被破坏。
S5、去PSG：将热氧化后的硅片，用氢氟酸去除背面及周边产生的PSG。
S6、碱抛：将去PSG后的硅片进行背面和边缘抛光，同时去除正面PSG。
S7、氧化退火：将碱抛后的硅片进行氧化及退火处理，在硅表面形成氧化硅层。
S8、在背面沉积钝化膜：采用PECVD二合一机台在退火后的硅片的背面进行镀膜工艺：保持硅片基体温度为300℃，通入笑气流量5000sccm，三甲基铝流量为60sccm，沉积120s制得8nm厚的氧化铝层；然后抽真空后升温至420℃，通入硅烷流量1200sccm，氨气流量4800sccm，沉积200s制得24nm厚的第三氮化硅层；通入硅烷流量1200sccm，氨气流量9600sccm，沉积180s制得18nm厚的第四氮化硅层；通入硅烷流量1200sccm，氨气流量13200sccm，沉积400s制得40nm厚的第五氮化硅层；硅片背面的膜层整体折射率为2.13，总厚度90nm。
S9、在正面沉积减反膜：采用PECVD二合一机台在完成背面镀层的硅片正面完成背面镀层的硅片正面进行镀膜工艺：保持硅片基体温度为530℃，通入硅烷流量1200sccm，氨气流量4800sccm，沉积120s制得15nm厚且折射率为2.3的第四氮化硅层；通入硅烷流量1200sccm，氨气流量8400sccm，沉积100s制得10nm厚且折射率为2.15的第五氮化硅层；通入烷流量1200sccm，氨气流量12000sccm，沉积120s制得15nm厚且折射率为2.06的第五氮化硅层；然后再通入硅烷流量800sccm，氮气流量7000sccm，笑气5000sccm，沉积130s制得厚度为15nm厚且折射率为1.8的氮氧化硅层；最后通入硅烷流量200sccm，笑气流量2000sccm，沉积150s制得20nm厚的多孔第三氧化硅层；硅片正面的膜层整体折射率为2.03，总厚度75nm。
S10、正背面致密氧化硅层：采用ALD原子层沉积法在半成品硅片的正面和背面分别沉积第一氧化硅层和第二氧化硅层的工艺包括：将半成品硅片设置于反应室中，在真空环境下先向反应室中通入六氯乙硅烷25sccm，持续4s，六氯乙硅烷会化学吸附在半成品硅片衬底表面，使过剩的六氯乙硅烷从反应室中排出，然后向反应室中通入臭氧25sccm，持续10s，臭氧和半成品硅片衬底表面的六氯乙硅烷反应生成氧化硅薄膜，使未反应的六氯乙硅烷和臭氧 从反应室中排出；反应室内压力为25mbar，半成品硅片的温度为300℃；以上步骤循环50次制得厚度为5nm的第一氧化硅层和第二氧化硅层。
S11、背面激光：根据背面图形设计采用对应的背激光图形，其中背面细副栅区域进行激光开孔增加接触，铝主栅和背电极区域不打激光。
S12、背面电极制备：采用丝网印刷方式，在背激光开槽后的硅片上，选用银浆，印刷背银电极和PAD点。
S13、背面电场制备：选用铝浆，采用目数360目、线径16μm、沙厚28μm、膜厚16μm的网板，通过丝网印刷方式同步印刷铝主栅和铝副栅。
S14、正电极主栅区印刷：采用正银浆料，在印刷了背面电极的硅片上丝网印刷制备正面电极。
S15、正面副栅区印刷：按照网板图形，采用正银浆料印刷正面副栅，采用520目、线径17um，纱厚11um、膜厚6um的网板。
S16、烧结：将印刷正面电极的硅片进行共烧结，烧结峰值温度760℃。
S17、电注入：将烧结后的电池片进行电注入处理。
S18、成品：将产品电池片测试、分选、包装入库。
实施例2
本申请实施例提供一种太阳电池及其制备方法，其包括以下步骤：
S1、制绒：采用单晶P型硅片，用碱进行正面和背面制绒形成绒面金字塔陷光结构。
S2、扩散：将制绒后硅片，用三氯氧磷和硅片在高温下进行反应，使正面扩散形成PN发射结。扩散后正表面薄层的方块电阻为165Ω/sq之间。
S3、激光SE：利用扩散过程中形成的磷硅玻璃为磷源，在扩散后硅片的正面且对应正电极栅线的金属化区域进行激光掺杂，形成重掺杂区，从而在硅片正面实现选择发射极的结构，重掺杂区的方块电阻为90Ω/sq之间。
S4、热氧：将激光SE后硅片通氧进行氧化，在正表面形成氧化层，保护正面PN结不被破坏。
S5、去PSG：将热氧化后的硅片，用氢氟酸去除背面及周边产生的PSG。
S6、碱抛：将去PSG后的硅片进行背面和边缘抛光，同时去除正面PSG。
S7、氧化退火：将碱抛后的硅片进行氧化及退火处理，在硅表面形成氧化硅层。
S8、在背面沉积钝化膜：采用PECVD二合一机台在退火后的硅片的背面进行镀膜工艺：保持硅片基体温度为300℃，通入笑气流量5000sccm，三甲基铝流量为60sccm，沉积120s制得8nm厚的氧化铝层；然后抽真空后升温至420℃，通入硅烷流量1200sccm，氨气流量4800sccm，沉积200s制得24nm厚的第三氮化硅层；通入硅烷流量1200sccm，氨气流量9600sccm，沉积180s制得18nm厚的第四氮化硅层；通入硅烷流量1200sccm，氨气流量13200sccm，沉积400s制得40nm厚的第五氮化硅层；硅片背面的膜层整体折射率为2.13，总厚度90nm。
S9、在正面沉积减反膜：采用PECVD二合一机台在完成背面镀层的硅片正面完成背面镀层的硅片正面进行镀膜工艺：保持硅片基体温度为530℃，通入硅烷流量1200sccm，氨气流量4800sccm，沉积120s制得15nm厚且折射率为2.3的第四氮化硅层；通入硅烷流量1200sccm，氨气流量8400sccm，沉积100s制得10nm厚且折射率为2.15的第五氮化硅层；通入烷流量1200sccm，氨气流量12000sccm，沉积120s制得15nm厚且折射率为2.06的第五氮化硅层；然后再通入硅烷流量800sccm，氮气流量7000sccm，笑气5000sccm，沉积130s制得厚度为15nm厚且折射率为1.8的氮氧化硅层；最后通入硅烷流量200sccm，笑气流量2000sccm，沉积150s制得20nm厚的多孔第三氧化硅层；硅片正面的膜层整体折射率为2.03，总厚度75nm。
S10、正背面致密氧化硅层：采用ALD原子层沉积法在半成品硅片的正面和背面分别沉积第一氧化硅层和第二氧化硅层的工艺包括：将半成品硅片设置于反应室中，在真空环境下先向反应室中通入六氯乙硅烷25sccm，持续4s，六氯乙硅烷会化学吸附在半成品硅片衬底表面，使过剩的六氯乙硅烷从反应室中排出，然后向反应室中通入臭氧25sccm，持续10s，臭氧和半成品硅片衬底表面的六氯乙硅烷反应生成氧化硅薄膜，使未反应的六氯乙硅烷和臭氧从反应室中排出；反应室内压力为25mbar，半成品硅片的温度为300℃；以上步骤循环100次制得厚度为10nm的第一氧化硅层和第二氧化硅层。
S11、背面激光：根据背面图形设计采用对应的背激光图形，其中背面细副栅区域进行激光开孔增加接触，铝主栅和背电极区域不打激光。
S12、背面电极制备：采用丝网印刷方式，在背激光开槽后的硅片上，选用银浆，印刷背银电极和PAD点。
S13、背面电场制备：选用铝浆，采用目数360目、线径16μm、沙厚28μm、膜厚16μm的网板，通过丝网印刷方式同步印刷铝主栅和铝副栅。
S14、正电极主栅区印刷：采用正银浆料，在印刷了背面电极的硅片上丝网印刷制备正面电极。
S15、正面副栅区印刷：按照网板图形，采用正银浆料印刷正面副栅，采用520目、线径17um，纱厚11um、膜厚6um的网板。
S16、烧结：将印刷正面电极的硅片进行共烧结，烧结峰值温度760℃。
S17、电注入：将烧结后的电池片进行电注入处理。
S18、成品：将产品电池片测试、分选、包装入库。
对比例1
本申请实施例提供一种太阳电池及其制备方法，其包括以下步骤：
S1、制绒：采用单晶P型硅片，用碱进行正面和背面制绒形成绒面金字塔陷光结构。
S2、扩散：将制绒后硅片，用三氯氧磷和硅片在高温下进行反应，使正面扩散形成PN发射结。扩散后正表面薄层的方块电阻为165Ω/sq之间。
S3、激光SE：利用扩散过程中形成的磷硅玻璃为磷源，在扩散后硅片的正面且对应正电极栅线的金属化区域进行激光掺杂，形成重掺杂区，从而在硅片正面实现选择发射极的结构，重掺杂区的方块电阻为90Ω/sq之间。
S4、热氧：将激光SE后硅片通氧进行氧化，在正表面形成氧化层，保护正面PN结不被破坏。
S5、去PSG：将热氧化后的硅片，用氢氟酸去除背面及周边产生的PSG。
S6、碱抛：将去PSG后的硅片进行背面和边缘抛光，同时去除正面PSG。
S7、氧化退火：将碱抛后的硅片进行氧化及退火处理，在硅表面形成氧化硅层。
S8、在背面沉积钝化膜：采用PECVD二合一机台在退火后的硅片的背面进行镀膜工艺：保持硅片基体温度为300℃，通入笑气流量5000sccm，三甲基铝流量为60sccm，沉积120s制 得8nm厚的氧化铝层；然后抽真空后升温至420℃，通入硅烷流量1200sccm，氨气流量4800sccm，沉积200s制得24nm厚的第三氮化硅层；通入硅烷流量1200sccm，氨气流量9600sccm，沉积180s制得18nm厚的第四氮化硅层；通入硅烷流量1200sccm，氨气流量13200sccm，沉积400s制得40nm厚的第五氮化硅层；硅片背面的膜层整体折射率为2.13，总厚度90nm。
S9、在正面沉积减反膜：采用PECVD二合一机台在完成背面镀层的硅片正面完成背面镀层的硅片正面进行镀膜工艺：保持硅片基体温度为530℃，通入硅烷流量1200sccm，氨气流量4800sccm，沉积120s制得15nm厚且折射率为2.3的第四氮化硅层；通入硅烷流量1200sccm，氨气流量8400sccm，沉积220s制得20nm厚且折射率为2.15的第五氮化硅层；通入烷流量1200sccm，氨气流量12000sccm，沉积350s制得35nm厚且折射率为2.06氮化硅层；硅片正面的膜层整体折射率为2.15，总厚度70nm。
S10、背面激光：根据背面图形设计采用对应的背激光图形，其中背面细副栅区域进行激光开孔增加接触，铝主栅和背电极区域不打激光。
S11、背面电极制备：采用丝网印刷方式，在背激光开槽后的硅片上，选用银浆，印刷背银电极和PAD点。
S12、背面电场制备：选用铝浆，采用目数360目、线径16μm、沙厚28μm、膜厚16μm的网板，通过丝网印刷方式同步印刷铝主栅和铝副栅。
S13、正电极主栅区印刷：采用正银浆料，在印刷了背面电极的硅片上丝网印刷制备正面电极。
S14、正面副栅区印刷：按照网板图形，采用正银浆料印刷正面副栅，采用520目、线径17um，纱厚11um、膜厚6um的网板。
S15、烧结：将印刷正面电极的硅片进行共烧结，烧结峰值温度760℃。
S16、电注入：将烧结后的电池片进行电注入处理。
S17、成品：将产品电池片测试、分选、包装入库。
对比例2
本申请实施例提供一种太阳电池及其制备方法，其包括以下步骤：
S1、制绒：采用单晶P型硅片，用碱进行正面和背面制绒形成绒面金字塔陷光结构。
S2、扩散：将制绒后硅片，用三氯氧磷和硅片在高温下进行反应，使正面扩散形成PN发射结。扩散后正表面薄层的方块电阻为165Ω/sq之间。
S3、激光SE：利用扩散过程中形成的磷硅玻璃为磷源，在扩散后硅片的正面且对应正电极栅线的金属化区域进行激光掺杂，形成重掺杂区，从而在硅片正面实现选择发射极的结构，重掺杂区的方块电阻为90Ω/sq之间。
S4、热氧：将激光SE后硅片通氧进行氧化，在正表面形成氧化层，保护正面PN结不被破坏。
S5、去PSG：将热氧化后的硅片，用氢氟酸去除背面及周边产生的PSG。
S6、碱抛：将去PSG后的硅片进行背面和边缘抛光，同时去除正面PSG。
S7、氧化退火：将碱抛后的硅片进行氧化及退火处理，在硅表面形成氧化硅层。
S8、在背面沉积钝化膜：采用PECVD二合一机台在退火后的硅片的背面进行镀膜工艺：保持硅片基体温度为300℃，通入笑气流量5000sccm，三甲基铝流量为60sccm，沉积120s制得8nm厚的氧化铝层；然后抽真空后升温至420℃，通入硅烷流量1200sccm，氨气流量4800sccm，沉积200s制得24nm厚的第三氮化硅层；通入硅烷流量1200sccm，氨气流量9600sccm，沉积180s制得18nm厚的第四氮化硅层；通入硅烷流量1200sccm，氨气流量13200sccm，沉积400s制得40nm厚的第五氮化硅层；硅片背面的膜层整体折射率为2.13，总厚度90nm。
S9、在正面沉积减反膜：采用PECVD二合一机台在完成背面镀层的硅片正面完成背面镀层的硅片正面进行镀膜工艺：保持硅片基体温度为530℃，通入硅烷流量1200sccm，氨气流量4800sccm，沉积120s制得15nm厚且折射率为2.3的第四氮化硅层；通入硅烷流量1200sccm，氨气流量8400sccm，沉积100s制得10nm厚且折射率为2.15的第五氮化硅层；通入烷流量1200sccm，氨气流量12000sccm，沉积120s制得15nm厚且折射率为2.06的第五氮化硅层；然后再通入硅烷流量800sccm，氮气流量7000sccm，笑气5000sccm，沉积130s制得厚度为15nm厚且折射率为1.8的氮氧化硅层；最后通入硅烷流量200sccm，笑气流量2000sccm，沉积150s制得20nm厚的多孔第三氧化硅层；硅片正面的膜层整体折射率为2.03，总厚度75nm。
S10、正背面非致密氧化硅层：采用PECVD二合一机台在半成品硅片的正面和背面分别 沉积第一氧化硅层和第二氧化硅层的工艺包括：保持硅片基体温度为530℃，通入硅烷流量600sccm，氨气流量12000sccm，沉积180s制得15nm厚且折射率为1.45的第一氧化硅层和第二氧化硅层。
S11、背面激光：根据背面图形设计采用对应的背激光图形，其中背面细副栅区域进行激光开孔增加接触，铝主栅和背电极区域不打激光。
S12、背面电极制备：采用丝网印刷方式，在背激光开槽后的硅片上，选用银浆，印刷背银电极和PAD点。
S13、背面电场制备：选用铝浆，采用目数360目、线径16μm、沙厚28μm、膜厚16μm的网板，通过丝网印刷方式同步印刷铝主栅和铝副栅。
S14、正电极主栅区印刷：采用正银浆料，在印刷了背面电极的硅片上丝网印刷制备正面电极。
S15、正面副栅区印刷：按照网板图形，采用正银浆料印刷正面副栅，采用520目、线径17um，纱厚11um、膜厚6um的网板。
S16、烧结：将印刷正面电极的硅片进行共烧结，烧结峰值温度760℃。
S17、电注入：将烧结后的电池片进行电注入处理。
S18、成品：将产品电池片测试、分选、包装入库。
试验例1
在-1500V、85％湿度和85℃标准测试条件下(IEC61215或UL1703标准)，分别测试实施例1～2和对比例1～2制得的太阳电池的正面PID 96H衰减和192H衰减，测试结果如表1所示。
表1太阳电池的正面PID 96H衰减和192H衰减
由表1可知，目前采用的对比例2正膜工艺，正面最外层为通过PECVD制备得到的疏松氧化硅PID衰减超过标准；对比例2正膜为三层纯氮化硅结构，PID衰减较对比例2有较大改善；实施例1为在对比例2的基础上正背面均通过ALD制备了5nm厚的致密氧化硅，抗PID性能大幅提升；实施例2进一步增加致密氧化硅厚度，PID衰减值进一步下降；对比例1为在实施例1的基础上无正背面致密氧化硅层步骤，PID衰减值提高。
试验例2
检测实施例1～2和对比例1～2制得的太阳电池的电性能，测试结果如表2所示。
表2太阳电池的电性能
由表1和表2可知，对比例1虽然相对对比例2正面抗PID性能有改善，但其电池转换效率低，采用实施例1和实施例2既能满足抗PID要求，又能满足电池转换效率要求。
综上所述，本申请实施例制得的太阳电池的正面PID 96H衰减<1％，192H衰减<2％。
以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本申请的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对申请专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改进，这些都属于本申请的保护范围。因此，本申请专利的保护范围应以所附权利要求为准。

Claims (15)

  1. 一种太阳电池的制备方法，其特征在于，其包括：提供半成品硅片，采用原子层沉积法在所述半成品硅片的正面和背面分别形成第一氧化硅层和第二氧化硅层；
    所述半成品硅片沿厚度方向包括依次层叠布置的至少一层氮化硅层、氧化铝层、硅层、至少一层氮化硅层、氮氧化硅层和第三氧化硅层，所述第一氧化硅层结合于所述第三氧化硅层表面，所述第二氧化硅层结合于所述氮化硅层表面。
  2. 如权利要求1所述的太阳电池的制备方法，其特征在于，所述第一氧化硅层和所述第二氧化硅层的厚度为5～10nm。
  3. 如权利要求1或2所述的太阳电池的制备方法，其特征在于，所述原子层沉积法包括：
    将所述半成品硅片设置于反应室中，向所述反应室中通入2～5s的气态硅基前驱体，然后向所述反应室中通入5～15s的气态氧化剂前驱体，所述硅基前驱体的流量为10～50sccm，所述氧化剂前驱体的流量为10～50sccm；以及
    重复上述步骤50～100次。
  4. 如权利要求3所述的太阳电池的制备方法，其特征在于，所述反应室在通入所述气态硅基前驱体前为真空环境。
  5. 如权利要求3或4所述的太阳电池的制备方法，其特征在于，所述硅基前驱体包括六氯乙硅烷、双(二乙氨基)硅烷、三(二甲氨基)硅烷和三甲硅烷基胺中的任意一种或多种，所述氧化剂包括氧气和臭氧中的至少一种。
  6. 如权利要求3至5中任一项所述的太阳电池的制备方法，其特征在于，所述反应室内压力为2～50mbar，所述半成品硅片的温度为150～400℃。
  7. 如权利要求3至6中任一项所述的太阳电池的制备方法，其特征在于，在每次完成所述气态硅基前驱体的通入后，所述气态硅基前驱体吸附在所述半成品硅片表面，使过剩的所述气态硅基前驱体从所述反应室中排出，再向所述反应室中通入所述气态氧化剂前驱体，完成反应后，使未反应的所述气态硅基前驱体和 所述气态氧化剂前驱体从所述反应室中排出，再进行下一次的沉积。
  8. 如权利要求1至7中任一项所述的太阳电池的制备方法，其特征在于，所述半成品硅片通过以下方法制得：
    分别在硅片的背面和正面沉积镀层；
    其中，背面的镀层包括第一氮化硅层、第二氮化硅层、第三氮化硅层和所述氧化铝层，正面的镀层包括第四氮化硅层、第五氮化硅层、第六氮化硅层、所述氮氧化硅层和所述第三氧化硅层。
  9. 如权利要求8所述的太阳电池的制备方法，其特征在于，采用气相沉积法在所述硅片的背面依次沉积得到所述氧化铝层、所述第三氮化硅层、所述第二氮化硅层和所述第一氮化硅层。
  10. 如权利要求8或9所述的太阳电池的制备方法，其特征在于，所述第三氮化硅层的折射率为2.2～2.3，所述第二氮化硅层的折射率为2.09～2.15，所述第一氮化硅层的折射率为2.00～2.06。
  11. 如权利要求8至10中任一项所述的太阳电池的制备方法，其特征在于，所述背面的镀层的折射率为2.10～2.15。
  12. 如权利要求8至11中任一项所述的太阳电池的制备方法，其特征在于，采用气相沉积法在所述硅片的正面依次沉积得到所述第四氮化硅层、所述第五氮化硅层、所述第六氮化硅层、所述氮氧化硅层和所述第三氧化硅层。
  13. 如权利要求8至12中任一项所述的太阳电池的制备方法，其特征在于，述第四氮化硅层的折射率为2.2～2.3，所述第五氮化硅层的折射率为2.09～2.17，所述第六氮化硅层的折射率为2.03～2.06，所述氮氧化硅层的折射率为1.55～1.9。
  14. 如权利要求8至13中一项所述的太阳电池的制备方法，其特征在于，所述正面的镀层的折射率为2～2.05。
  15. 一种太阳电池，其特征在于，其由权利要求1至14中任一项所述的太阳电池的制备方法制得。
PCT/CN2023/102337 2022-07-08 2023-06-26 太阳电池及其制备方法 Ceased WO2024007874A1 (zh)

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