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CN-117467950-B - Explosion-proof membrane silicon solar cell based on physical deposition technology and production process thereof

CN117467950BCN 117467950 BCN117467950 BCN 117467950BCN-117467950-B

Abstract

The invention discloses an explosion-proof film silicon solar cell based on physical deposition technology and a production process thereof, the cell structure comprises a silicon substrate, a P++ emitter, an alumina layer, a silicon nitride layer and a metal electrode are sequentially prepared from inside to outside on the front surface, the back surface is sequentially provided with a silicon oxide tunneling layer, a lightly doped and hydrogen-less polycrystalline silicon layer, a heavily doped and hydrogen-rich polycrystalline silicon layer, a silicon nitride layer and a metal electrode from inside to outside. The explosion-proof film silicon solar cell production process based on the PVD technology can not cause winding plating, reduces the generation of explosion film defects by adjusting the [ H ] content in the TOPCon structure, complements the [ H ] by subsequent ammonia annealing, and ensures the passivation capability of a film.

Inventors

  • ZHANG GENG
  • QIAO XIAOQIN
  • GUO FEI
  • ZOU JINWEI
  • XIONG DAMING
  • LIN JIANWEI

Assignees

  • 山西中来光能电池科技有限公司

Dates

Publication Date
20260505
Application Date
20231031

Claims (7)

  1. 1. The production process of the explosion-proof film silicon solar cell based on the physical deposition technology is characterized by comprising the following steps of: Step 1, performing texturing, cleaning and boron diffusion processes on a silicon wafer; Step 2, preparing a P++ emitter by laser doping at a position on the silicon wafer where metal grid line printing is needed by laser; step 3, adopting a chain type machine table, and removing borosilicate glass on the back surface and the side surface of the silicon wafer by using an HF aqueous solution; Step 4, performing alkali polishing on the back surface of the silicon wafer, and after pre-cleaning and polishing, increasing the alkali content in the post-cleaning solution, and microetching the polished surface of the silicon wafer; Preparing TOPCon a structure on the back of a silicon wafer by using a PVD (physical vapor deposition) technology, namely preparing an ultrathin tunneling oxide layer firstly, and dividing the process of growing doped amorphous silicon into two parts, namely (1) bombarding a silicon target material in a cavity by using argon ions to deposit an intrinsic amorphous silicon film on the back surface of the silicon wafer, at the moment, not introducing a doping source, and maintaining the deposition temperature at 350-400 ℃ to reduce the content of [ H ] in the film, (2) introducing PH 3 gas after depositing the intrinsic amorphous silicon film, and doping phosphorus element to prepare the doped amorphous silicon layer; Step 6, annealing for 300-500 s at 600 ℃, adding ammonia gas in the traditional nitrogen atmosphere, stopping introducing ammonia gas after 300s, raising the annealing temperature to 850 ℃ at a speed of 10 ℃ per minute, keeping the constant temperature for 2000s to activate doping atoms in the doped amorphous silicon layer, and supplementing [ H ] reduced in the PVD process in the step 5; Step 7, after the annealing is finished, BOE cleaning is carried out; step 8, preparing an alumina passivation layer on the front surface of the silicon wafer by utilizing atomic layer deposition equipment; step 9, preparing silicon nitride antireflection films on the front and back surfaces of the silicon wafer by utilizing a plasma enhanced chemical deposition system so as to reduce light reflection; And 10, coating metal slurry on the front side and the back side of the silicon wafer by using screen printing equipment, preparing a metal grid line by high-temperature processing of a sintering furnace, enabling the metal material to be combined with silicon to form an alloy, and leading out photo-generated carriers to finish the preparation of the battery.
  2. 2. The production process of the explosion-proof film silicon solar cell based on the physical deposition technology is characterized in that in the step 1, the silicon wafer is subjected to texturing treatment, a surface cutting damage layer is removed, a textured texture structure is formed on the surface of the silicon wafer, light loss is reduced, and the silicon wafer is an n-type silicon wafer with the thickness of 130um and the sheet resistance of 1 Ω/≡.
  3. 3. The process for producing the explosion-proof film silicon solar cell based on the physical deposition technology according to claim 2, wherein in the step 1, after the silicon wafer is textured and cleaned, the silicon wafer is put into a boron diffusion furnace tube for boron diffusion, and the boron diffusion process comprises four steps of pre-oxidation, deposition, propulsion and post-oxidation.
  4. 4. The process for producing the explosion-proof film silicon solar cell based on the physical deposition technology according to claim 3, wherein the deposition time is reduced to 90-120 s, the advancing time is reduced to 350-400 s, and the sheet resistance of the silicon wafer after boron diffusion is 150Ω/≡s.
  5. 5. The process for producing the explosion-proof membrane silicon solar cell based on the physical deposition technology, which is characterized in that in the step 4 alkali polishing process, a silicon wafer is placed into a post-cleaning tank, pure water, sodium hydroxide and hydrogen peroxide are added into the tank according to the proportion of 90:1:4, the alkali content in the solution in the tank is increased, the proportion of the pure water, the sodium hydroxide and the hydrogen peroxide in the tank reaches 90:3:4, and then the surface of the silicon wafer is cleaned through hydrochloric acid and hydrofluoric acid after cleaning.
  6. 6. The process for producing an anti-explosion film silicon solar cell based on the physical deposition technology according to claim 5, wherein the reflectivity of the back surface of the silicon wafer is properly reduced from 35% to 25-30% by the treatment of the step 4.
  7. 7. The explosion-proof film silicon solar cell is characterized in that the cell is manufactured by the production process according to any one of claims 1-6, the cell structure comprises a silicon substrate, a P++ emitter, an aluminum oxide layer, a silicon nitride layer and a metal electrode are sequentially prepared on the front surface of the silicon substrate from inside to outside, and a silicon oxide tunneling layer, a lightly-doped and low-hydrogen polycrystalline silicon layer, a heavily-doped and hydrogen-rich polycrystalline silicon layer, a silicon nitride layer and a metal electrode are sequentially prepared on the back surface of the silicon substrate from inside to outside.

Description

Explosion-proof membrane silicon solar cell based on physical deposition technology and production process thereof Technical Field The invention relates to the technical field of solar cells, in particular to an explosion-proof membrane silicon solar cell based on a physical deposition technology and a production process thereof. Background Along with the gradual improvement of energy crisis and people's environmental protection consciousness, green sustainable solar energy is gradually paid attention to. Solar cells are microelectronic devices that directly convert light energy into electrical energy, and have been developed over the years in a variety of structures including PERC (emitter back passivation cell), TOPCon (tunnel oxide passivation solar cell), HJT (heterojunction solar cell), and the like. Currently, TOPCon batteries are certainly the mainstream at present, considering the battery efficiency and the manufacturing cost comprehensively. In industrial manufacturing, the key structure of TOPCon cells is mainly manufactured by three routes, i.e., LPCVD (low pressure chemical vapor deposition), PECVD (plasma enhanced chemical vapor deposition) and PVD (physical vapor deposition). The traditional TOPcon structure is prepared by LPCVD (low pressure chemical vapor deposition), which is a classical preparation method, and the development of many years makes the technology have high maturity, simple process and low cost. However, as a vapor deposition technique, even if two silicon wafers are stacked together for processing, a product is deposited on the other side as well as the side, that is, "wrap-around plating" is generated. Since the deposited material properties on both sides of the cell are quite opposite, the plating around can lead to leakage and degradation of the cell properties. PVD techniques achieve reduced process time, manufacturing costs, and increased yields, however, it is generally necessary to produce n+ poly layers by introducing a PH 3 gas into the PVD apparatus to dope the P atoms, so that the a-Si layer contains a high concentration of H, i.e., hydrogenated amorphous silicon (a-Si: H), most of which will exist as Si-H bonds at the film's disordered and interstitial surfaces, but some of which may also remain in large interstitial spaces as H 2 molecules, the mass density of a-Si: H is slightly lower than that of pure a-Si films, and the H present in the internal voids during annealing will recombine and flow out, which will tend to form loose polysilicon grains and cause build up pressure at the c-Si/SiOx and SiOx/poly interfaces leading to film delamination, i.e., popping (a phenomenon as shown in fig. 1 and 2), which will result in passivation film passivation performance failure, resulting in reduced cell performance, and reduced efficiency. However, the conventional LPCVD process rarely generates a film explosion mainly because the deposition is performed at a high temperature, si-H bonds are opened during the deposition, and the content of [ H ] in the film layer in the form of Si-H bonds is low, so that in the subsequent annealing, the [ H ] is combined to generate H 2 to accumulate air pressure, which results in low probability of film explosion. Therefore, the generation of the rupture film can be effectively reduced by reducing the content of [ H ], however, the existence of [ H ] is also the guarantee of the passivation performance of the SiOx/n+poly combined passivation layer, because a-Si has localized state band tails near the bottom of a conduction band and the top of a valence band due to the lack of long-range order, a large number of band gap states are formed in the middle of a forbidden band due to the existence of a large number of suspension bonds, and the [ H ] has smaller volume and mass and can easily enter into a disordered network structure of a-Si without changing the network structure, passivate the suspension bonds and reduce the composite density, so that the existence of a certain amount of [ H ] is also necessary. It can be seen that LPCVD technique can reduce the generation of rupture but can produce around plating, while PVD technique can reduce the generation of around plating but can bring about the problem of rupture. Therefore, it is important to develop a solar cell production technology that can reduce the number of plating windings and prevent the rupture film. Disclosure of Invention In view of the above, the present invention provides an explosion-proof film silicon solar cell based on physical deposition technology and a production process thereof, and designs a solar cell process technology based on PVD technology, which can reduce plating around and prevent explosion. To achieve the above object, the present invention adopts the following: The invention provides an explosion-proof film silicon solar cell production process based on a physical deposition technology, which is characterized by comprising the following steps of: Step 1