Phosphorous diffusion control method used for solar cell silicon slices

Abstract

The invention discloses a phosphorous diffusion control method used for solar cell silicon slices. After loading of the silicon slices, the silicon slices are pushed into a processing furnace, oxygen is aerated into the processing furnace and the processing furnace is heated. The silicon slices are oxidized to generate a silica protection layer, then the processing furnace is cooled to the temperature that phosphoric anhydride can precipitate, phosphorus oxychloride, oxygen and nitrogen are aerated, the phosphoric anhydride generated by the phosphorus oxychloride decomposition precipitates on the surfaces of the silicon slices, and reacts with the silicon slices to form phosphor, then the phosphor diffuses toward insides of the silicon slices, and finally oxygen is aerated to rise the temperature so that the phosphorus oxychloride can react fully and diffuses toward insides of the silicon slices to form PN junctions. According to the method, by high-temperature oxidation and low-temperature precipitation of the silicon slices, silicon grid damage of the silicon slices is effectively reduced, the service life of minority carriers on the surfaces of the silicon slices is prolonged, and evenness of the PN junctions is improved.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a phosphorus diffusion control method for silicon wafers of solar cells. Background technique [0002] A solar cell, also known as a photovoltaic cell, is a semiconductor device that converts the sun's light energy directly into electrical energy. Because it is a green product, does not cause environmental pollution, and is a renewable resource, solar cells are a new energy source with broad development prospects in today's energy shortage situation. [0003] Among them, the core process of manufacturing solar cells is to form the emitter on the silicon wafer through phosphorus diffusion, that is, the PN junction, while the process of the traditional diffusion process is: loading silicon wafers into the furnace → heating up in a nitrogen atmosphere → stabilizing the temperature → nitrogen carrying POCL3+ O2 undergoes a diffusion reaction in the processing furnace → cools dow...

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Problems solved by technology

In general, the inhomogeneity of the PN junction formed by diffusion directly affects the effect of sintering. In the above technical scheme, only the flow of POCL3 is used to ensure the uniformity of the PN junction after phosphorus diffusion, and the operability is not high. If the phosphorus Too high a concentration will in turn aggravate the generation of dead layers on the surface of silicon wafers

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