Phosphorus diffusion method for crystalline silicon solar cells

Abstract

The invention discloses a phosphorus diffusion method of a crystalline silicon solar cell. The phosphorus diffusion method comprises the following steps: (1) heating a diffusion furnace to 760-780 DEG C, and feeding; (2) adjusting the temperature to 780-790 DEG C; (3) introducing a phosphorus source carrying gas and dry oxygen for low-temperature diffusion; (4) stopping introducing the phosphorus source carrying gas and the dry oxygen, increasing the temperature inside the furnace to 820-840 DEG C, and boosting; (5) performing constant-temperature boosting; (6) reducing the temperature inside the diffusion furnace to 700-750 DEG C, and performing cooling diffusion; and (7) cooling, and discharging. As annealing steps and steps of two times of diffusion are combined, the problem that in the prior art the surface doping solubility caused by annealing is reduced secondarily and impurities are widely distributed can be solved, the impurity distribution meets the shallow junction and narrow impurity requirements, moreover the yield is increased, and the photoelectric conversion efficiency can be improved.

Description

technical field [0001] The invention relates to a phosphorus diffusion method for a crystalline silicon solar cell, which belongs to a diffusion junction process for manufacturing a solar cell and belongs to the technical field of solar cells. Background technique [0002] Conventional fossil fuels are increasingly depleted. Among all sustainable energy sources, solar energy is undoubtedly the cleanest, most common and most potential alternative energy source. At present, among all solar cells, crystalline silicon solar cells are one of the solar cells that have been widely commercialized. This is due to the extremely abundant reserves of silicon materials in the earth's crust. Cells have excellent electrical and mechanical properties, therefore, crystalline silicon solar cells occupy an important position in the field of photovoltaics. [0003] The manufacturing process of crystalline silicon solar cells widely used at present has also been standardized. The main steps are...

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Problems solved by technology

[0004] However, the high-temperature treatment in the second step will cause large temperature fluctuations and large differences in each temperature zone in the furnace tube, resulting in inconsistent PN junctions

[0005] Therefore, the development of a phosphorus diffusion method for crystalline silicon solar cells can not only ensure the surface doping solubility, make a large number of impurities diffuse and conform to the shallow junction and narrow impurity distribution, but also play a role in segregation and gettering of impurities, ensuring The consistency of the PN junction is a goal that those skilled in the art have been longing to achieve but have not been able to achieve.

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