Boron diffusion method of crystalline silicon solar cell

Abstract

The invention discloses a boron diffusion method of a crystalline silicon solar cell, wherein the method comprises the following steps: (1), arranging a silicon chip subjected to felting and cleaning processes in a diffusion furnace pipe, heating to 900 DEG C to 1100 DEG C, introducing nitrogen, a relatively large amount of boron source and oxygen, and performing boron diffusion, wherein the diffusion time is 5min to 60min; (2), keeping the temperature in the step (1), introducing nitrogen, a relatively small amount of boron source and oxygen, and performing boron diffusion, wherein the diffusion time is 15min to 80min; (3), keeping the temperature in the step (1) or heating to 910 DEG C to 1100 DEG C, introducing nitrogen, a relatively large amount of boron source and oxygen, and performing boron diffusion, wherein the diffusion time is 2min to 30min; and (4) finishing the diffusion process. With the adoption of the boron diffusion method, the high impurity concentration is formed within small depth range of the surface of the silicon chip, so as to be beneficial to forming of excellent ohm contact; the impurity concentration of the large depth range of a diffusion layer is reduced; the auger recombination and combination generated by nudged defect are reduced, the minority carrier lifetime is prolonged, so the property of the cell is enhanced.

Description

Technical field [0001] The invention relates to a boron diffusion method for a crystalline silicon solar cell, belonging to the field of crystalline silicon solar cell manufacturing. Background technique [0002] Conventional fossil fuels are increasingly depleted. Among the existing sustainable energy sources, solar energy is undoubtedly the cleanest, most common and most potential alternative energy source. At present, among all solar cells, silicon solar cells are one of the solar cells that have been commercialized on a large scale. This is because silicon materials have extremely rich reserves in the earth's crust. At the same time, compared to other types of solar cells, silicon solar cells With excellent electrical and mechanical properties, silicon solar cells occupy an important position in the photovoltaic field. Therefore, the research and development of cost-effective silicon solar cells has become one of the main research directions of photovoltaic companies in vari...

AI Technical Summary

Problems solved by technology

[0004] However, the concentration of boron atoms formed by the above-mentioned diffusion method gradually decreases from the surface of the silicon wafer to the interior of the silicon wafer, but the decrease is relatively slow, and the boron atoms with a higher concentration are distributed in a wider range.

However, the high concentration of boron atoms may cause severe Auger recombination, which may lead to distortion of the silicon atom lattice and induce a large number of defects. These deep-level defects will also recombine and reduce the minority carrier lifetime; Lower surface concentration is not conducive to the formation of good ohmic contacts, thereby affecting battery performance

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