Boron diffusion method of solar cell and manufacturing method of solar cell

Abstract

The invention provides a boron diffusion method of a solar cell. The boron diffusion method comprises the steps of putting a silicon wafer into a diffusion furnace, and raising the temperature in thediffusion furnace to a first temperature; carrying out pre-oxidation operation on the silicon wafer to form an oxide layer on the surface of the silicon wafer; introducing nitrogen carrying a boron source, medium-flow nitrogen and oxygen into the diffusion furnace, and performing first boron diffusion on the surface of the silicon wafer; introducing nitrogen carrying a boron source, large-flow nitrogen and oxygen into the diffusion furnace, and carrying out second boron diffusion on the surface of the silicon wafer; introducing nitrogen carrying a boron source, small-flow nitrogen and oxygen into the diffusion furnace, and performing third boron diffusion on the surface of the silicon wafer; and reducing the temperature in the diffusion furnace and carrying out boat-out operation on the silicon wafer. The invention further provides a manufacturing method of the solar cell. By implementing the method, the diffusion uniformity of each region in the diffusion furnace can be effectively improved.

Description

technical field [0001] The invention relates to the field of photovoltaic technology, in particular to a boron diffusion method of a solar cell and a manufacturing method of the solar cell. Background technique [0002] The preparation of PN junction is one of the key steps in the solar cell manufacturing process. In the prior art, the PN junction of the solar cell is usually prepared by the liquid source diffusion method. Specifically, insert the silicon wafer to be diffused on the quartz boat, then put the quartz boat loaded with the silicon wafer into the diffusion furnace, and pass the diffusion source and process gas (such as nitrogen, oxygen, etc.) under certain temperature conditions. The product of the reaction between the diffusion source and the process gas adheres to the surface of the silicon wafer and reacts with the silicon wafer to generate dopant atoms. The dopant atoms enter the surface of the silicon wafer through the process of thermal diffusion, thereby ...

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Problems solved by technology

Since boron tribromide maintains a liquid state and has a high density under high temperature conditions, it is difficult to distribute boron tribromide evenly inside the diffusion furnace through nitrogen, resulting in the loss of silicon wafers near the furnace mouth and furnace tail regions of the diffusion furnace. The uniformity of diffusion resistance is poor, which affects the conversion efficiency of solar cells and the consistency of product performance

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