Double-sided selective emitter high-efficiency crystalline silicon cell and preparation method thereof

Abstract

The invention belongs to the field of solar photovoltaic industry and particularly provides a double-sided selective emitter efficient crystalline silicon cell and a preparation method thereof. The double-sided selective emitter efficient crystalline silicon cell is characterized in that a double-sided selective emitter structure is adopted, a boron-doped heavily-doped region is a polycrystallinesilicon structure in which aluminum oxide replaces silicon oxide to serve as a tunneling layer, a constant surface concentration increase fill factor (FF) exceeding 1E20atom/cm <3> can be achieved, alightly-expanded region is pure boron doping, a heavily-expanded boron doping process and a lightly-expanded boron doping process can be realized in one step, and the process is simplified. Silicon oxide is adopted as a tunneling layer for a phosphorus-doped region, a heavily-doped region is of a double-layer poly structure, the surface concentration is high, metallization contact is improved, a lightly-expanded region is of a single-layer lightly-doped poly structure, and then the open-circuit voltage (Voc) is increased. The formation of the double-sided selective emitter effectively utilizesa mask etching mode. The double-sided selective emitter efficient crystalline silicon cell is advantaged in that the structure can effectively improve battery efficiency, and is suitable for batch production.

Description

technical field [0001] The invention belongs to the field of solar crystal silicon cells, in particular to a double-sided selective emitter high-efficiency crystal silicon cell and a preparation method thereof. Background technique [0002] The pursuit of high-efficiency cells is a development trend in the photovoltaic industry. The solution that takes into account both cost and process is the n-TOPCon cell, which uses an ultra-thin oxide layer and doped thin-film silicon to passivate the back of the cell. Among them, the backside oxide layer has a thickness of 1.4nm and is grown by wet chemical method. Then on the oxide layer, 20nm phosphorous-doped amorphous silicon is deposited, and then annealed to recrystallize and strengthen the passivation effect. It will become the next-generation mainstream product after PERC. For the existing n-TOPCon battery mass production process, its efficiency has not widened the gap with PERC batteries, and the efficiency difference is only...

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Problems solved by technology

However, the efficiency of the existing mass production process of n-TOPCon batteries has not widened the gap with PERC batteries, and the efficiency difference is only 0.5%. Therefore, how to improve the efficiency of batteries with this structure has become a top priority.

[0003] The conventional boron-doped selective emitter on the front side is difficult to realize by conventional etching and laser or APCVD, and the current technology is immature

However, the use of silicon oxide as the tunneling layer cannot passivate boron-doped

The conventional selective emitter on the back side is the existing technical solution of etching and laser, but the laser method cannot be used for phosphorus-doped polysilicon, because the laser will damage the tunnel oxide layer, and the simple etching solution is suitable for polysilicon with uniform doping concentration The structure is also infeasible

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