A kind of preparation method of boron back field solar cell

Abstract

The invention discloses a method for preparing a boron-back-field solar cell. The method comprises the following steps: texturing a front face of a silicon wafer; implanting B ions to a back face of the silicon wafer; carrying out diffusion annealing on the silicon wafer; removing phosphor silicate glass; forming an anti-reflection film on the front face of the silicon wafer; forming a back electrode and an aluminum back field on the back face of the silicon wafer; forming a positive electrode on the front face of the silicon wafer. By adopting the method disclosed by the invention, an efficient boron-doped p<+> layer can be formed on the back face of the silicon wafer through a high-temperature process once, so that the complexity of the method is simplified, and the photoelectric transformation efficiency of the solar cell is increased.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a method for preparing a boron back field solar cell. Background technique [0002] In order to further improve the photoelectric conversion efficiency of silicon solar cells, a P+ layer is usually prepared on the back side of the silicon wafer, that is, the backlight side. The P+ layer can reduce the probability of minority carriers recombining on the back of the silicon wafer, and can also be used as the metal electrode on the back. [0003] The most conventional and simplest way to prepare the p+ layer is to deposit an aluminum film on the back of the silicon wafer by sputtering and other techniques, and then perform heat treatment at a temperature of 800 ° C to 1000 ° C to alloy the aluminum film and silicon and internal diffusion to form a P+ layer doped with high aluminum concentration. [0004] Due to the low solid solubility of silicon wafers for aluminum, the dopin...

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Problems solved by technology

[0005] Although boron doping on the back of the silicon wafer can increase the doping concentration and improve cell efficiency, the use of boron doping to form the P+ layer will also bring some disadvantages. For example, the boron diffusion process needs to be carried out at a temperature above 1000 ° C. The process is not easy to control; silicon wafers will introduce new defects during the high-temperature process, which will lead to a decrease in the photoelectric conversion efficiency of solar cells; using the conventional boron diffusion process for boron doping on the back, silicon wafers need to be separately treated with phosphorus (to form P-N on the front of the solar cell) Junction) diffusion and boron diffusion, and the two diffusion processes will lead to complex manufacturing process, high production cost, and low output of diffusion furnace; and multiple high-temperature processes will significantly reduce the photoelectric conversion efficiency of solar cells

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