Phosphorus diffusion gettering and cleaning method suitable for N-type silicon wafer

Abstract

The invention discloses a phosphorus diffusion gettering and cleaning method suitable for an N-type silicon wafer. The phosphorus diffusion gettering and cleaning method comprises the steps of carrying out pre-cleaning, double-sided phosphorus diffusion gettering, chain-type single-sided PSG removal, post-cleaning (groove-type single-side suede optimization), groove-type single-sided PSG removal, double-suede size regulation and control and spire smoothing treatment on the N-type silicon wafer. The method provided by the invention not only can better improve the quality of the N-type silicon wafer, but also can effectively control the thinning amount of the silicon wafer in the treatment process, is beneficial to control and popularization of HJT battery silicon wafer flaking, can also improve and regulate the concentration of active phosphorus on the single surface, improves carrier transport through the formed high-low junction effect, and is beneficial to improving the battery efficiency. And the size difference of textured pyramids on the two surfaces of the silicon wafer can be realized, and special requirements are met. The phosphorus diffusion gettering and cleaning method suitable for the N-type silicon wafer has the advantages of being easy to operate, low in energy consumption, small in silicon wafer thinning amount, good in gettering effect and the like, the use value is high, and the application prospect is good.

Description

technical field [0001] The invention belongs to the technical field of N-type battery preparation, and relates to a phosphorus diffusion gettering and cleaning method suitable for N-type silicon wafers. Background technique [0002] N-type cells, including HJT cells and TOPCon cells, have received extensive attention and research recently due to their high theoretical efficiency, low light decay, good weak light response, and bifacial power generation. GW-scale mass production lines have been formed. . N-type silicon wafer is an important production material for HJT cells and TOPCon cells, and its quality has a great influence on the efficiency of HJT cells and TOPCon cells. The current industry N-type silicon wafers not only have low production capacity, but also uneven quality of silicon wafers, which largely hinders the development of N-type battery technology. [0003] In order to improve the influence of N-type silicon wafer quality on cell efficiency, the industry ma...

AI Technical Summary

Problems solved by technology

However, the conventional phosphorus diffusion and gettering generally adopts double-sided high-temperature deep tubular phosphorus diffusion and gettering. Although it can improve the quality of N-type silicon wafers, the double-sided pre-cleaning and polishing thinning, and the thinning of highly deeply doped layers and large After the thinning treatment of the suede surface, the thickness of N-type silicon wafers is too much, which increases the difficulty of process control, which is not conducive to the promotion of N-type silicon wafers.

Another method is to absorb getter by chain diffusion annealing after surface coating, that is, coat a layer of phosphorous slurry layer on at least one surface of the textured silicon wafer, and perform chain diffusion annealing on the coated phosphorous slurry layer. The annealing includes a heating stage, a constant temperature stage and a cooling stage. The heating stage and the cooling stage both contain a sudden temperature change of not less than 30°C / min, so that the phosphorus slurry layer and the impurities in the silicon wafer are miscible to form a phosphorus-silicon gettering layer. , to remove the phosphorus-silicon layer, the phosphorus diffusion gettering technology is complicated to operate, high energy consumption, high consumption of cleaning chemicals, and poor gettering effect

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