Local back surface field passivation contact cell and preparation method thereof

Abstract

The invention discloses a local back surface field passivation contact cell and a preparation method thereof. The cell comprises a silicon wafer main body, a boron diffusion layer, a front passivation film, a positive electrode, a tunneling oxide layer, a field passivation layer, a back passivation film and a back electrode; the boron diffusion layer, the front passivation film and the positive electrode are sequentially laid on the front surface of the silicon wafer main body; the tunneling oxide layer, the field passivation layer, the back passivation film and the back electrode are sequentially laid on the back surface of the silicon wafer main body; and the field passivation layer is provided with a first region and a second region which are different in doping concentration. The field passivation layer is provided with the first region and the second region which are different in doping concentration, the first region is in contact with the back electrode of the cell, namely a metal contact area, the high doping concentration is achieved, and it is guaranteed that the first region has small electrode contact resistance and electron tunneling resistance; and the second region is not in contact with the back electrode of the cell, namely a non-metal contact region, so that the doping concentration is relatively low, auger recombination of the non-metal contact region is reduced, parasitic absorption of the non-metal contact region is further reduced, and the conversion efficiency of the tunneling oxidation passivation contact cell is improved.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a local back field passivation contact cell and a preparation method thereof. Background technique [0002] TOPCon batteries and HIT batteries, as the next generation of high-efficiency batteries that can be mass-produced at present, have been extensively studied by companies and scientific research institutions. Judging from the compatibility of existing PERC cell production lines, TOPCon only needs to add polysilicon coating equipment and boron diffusion equipment to achieve lower transformation costs to improve cell efficiency. Therefore, TOPCon battery is more compatible with the current production line of PERC battery, and it is the most popular high-efficiency battery technology. [0003] Among the factors currently restricting the efficiency improvement of TOPCon cells, one of them is the parasitic absorption produced by the thicker polysilicon layer on the back. Para...

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Problems solved by technology

Due to the use of wet process in this method, the possibility of battery pollution is increased, which will lead to a decrease in battery yield and even affect the effic

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