Method for removing poly-Si winding plating for manufacturing Topcon battery

Abstract

The invention discloses a method for removing poly-Si winding plating for manufacturing a Topcon battery. The method comprises the steps of: 1) removing a damaged layer from an original silicon wafer,and performing double-sided texturing; 2) finishing the front surface boron diffusion doping process of the obtained textured silicon wafer, and reserving a borosilicate glass layer on the front surface; 3) coating the front surface of a coating film to grow a layer of SiNx film on the borosilicate glass layer; 4) polishing the back surface and etching the edges of the back surface, removing a boron doped layer, and insulating the front surface and the back surface of the boron doped layer; 5) growing a tunnel oxide layer and a polycrystalline silicon layer on the back surface; 6) injecting aphosphorus source into the polycrystalline silicon layer; 7) removing organic matters and surface metal ion pollution; 8) removing the SiNx film, the poly-Si layer and the borosilicate glass layer; 9) annealing the back surface to form N+ doping on the poly-Si layer; 10) plating the SiNx film on the back surface, and plating a composite film layer of Al2O3 and SiNx on the front surface; and 11) respectively performing silk-screen printing on the front and back surfaces of the battery structure coated with the film, and performing sintering to complete metallization of the front and back surfaces of the battery structure. The method is good in stability and easy to operate, and is beneficial to industrialized production.

Description

technical field [0001] The invention belongs to the technical field of photovoltaics, and in particular relates to a method for removing poly-Si winding plating used for making Topcon cells. Background technique [0002] Tunnel Oxide Passivated Contact (TOPCon) battery technology is based on N-type silicon substrates, the front surface adopts a stacked film passivation process, and the back surface adopts ultra-thin silicon oxide and doped polysilicon (poly-Si ) tunneling oxide layer passivation contact structure, which can allow majority carriers to penetrate the oxide layer and block minority carriers, effectively realize the selective passage of carriers, and can greatly reduce the number of The recombination rate of carriers can not only achieve a surface passivation effect comparable to that of a heterojunction structure, but also be compatible with high-temperature processes, and avoid the high recombination problem caused by electrode contacts. Thus TOPCon cells have...

AI Technical Summary

Problems solved by technology

In this way, during the long-term high-temperature deposition process, poly-Si wrapping will occur on the front surface of the battery. If the poly-Si wrapping on the front surface is not removed cleanly, polysilicon marks will be left on the front surface, making the appearance of the battery poor. Moreover, the residual polysilicon on the front surface will reduce the passivation characteristics of the front surface, thereby affecting the conversion efficiency of the battery side.

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