Diffusion process of silicon-wafer laser doping SE

Abstract

The invention relates to a diffusion process of a silicon-wafer laser doping SE. According to the process, after formation of a diffusion first phosphorus layer and a diffusion second phosphorus layer on a surface of a silicon wafer, phosphorus attachment layer deposition processing is carried out to form a phosphorus attachment layer on the surface of the silicon after diffusion. With the phosphorus attachment layer, a problem of insufficient PSG concentration of laser ablation is solved; the phosphorus attachment layer is easy to remove during the follow-up phosphorus washing and removing process and thus the low-surface-concentration lightly-doped region is kept at the emitter, so that problems of poor ohmic contact and packing factor reduction caused by low PSG concentration during laser doping are solved.

Description

technical field [0001] The invention relates to the technical field of solar cell preparation, in particular to a diffusion process for silicon wafer laser doping SE. Background technique [0002] In the current field of solar cell technology, the application of high-efficiency cell technology is constantly improving. For example, high-efficiency cells such as PERC have continuously improved their conversion efficiency. In the continuous stacking technology, one of them can be doped with laser to prepare selective emission. Electrode (SE) cells. The preparation of SE cells mainly has two characteristics: 1) the contact area between the metal grid line and the silicon wafer is a heavily doped area, which can form a good ohmic contact and improve the fill factor; 2) the light receiving area is a lightly doped area, which can improve Short-wave response, low surface concentration reduces the recombination of minority carriers, thereby increasing the open circuit voltage and sh...

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Problems solved by technology

[0003] The technical problem to be solved by the present invention is: in the SE technology, the higher the square resistance, the higher the opening voltage and current, but the higher the square resistance, the less the phosphorus source diffuses, which will be caused by the phosphorus source during laser ablation. Insufficiently, the ablation area does not form a good heavy doping, which leads to poor ohmic contact, a decrease in fill factor, and a decrease in cell efficiency. In order to overcome the deficiencies in the prior art, the present invention provides a silicon wafer laser-doped SE Diffusion process to solve the technical problem of insufficient PSG concentration on the surface of the silicon wafer due to the high square resistance of the diffusion process in the existing laser SE technology, which eventually leads to poor ohmic contact in the heavily doped area of ​​the silicon wafer.

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