A kind of p-type monocrystalline silicon boron back field bifacial battery and preparation method thereof

Abstract

The invention discloses a P-type single crystal silicon boron back field double-sided battery and a preparation method thereof. The invention belongs to the technical field of solar cells, and solves the problem that boron doping cannot be realized on a P-type single crystal silicon substrate by using a laser in the prior art. The invention provides a method for preparing a P-type monocrystalline silicon-boron back-field double-sided battery, comprising the following steps: providing a P-type silicon substrate, cleaning and texturing the P-type silicon substrate; Phosphorus diffusion is performed on the textured surface to form a phosphorus expansion area; wet etching is performed on the back of the P-type silicon substrate to remove side junctions and partial back junctions; after the wet etching of the back of the P-type silicon substrate is completed, deposit on it Borosilicate glass layer; deposit absorbing layer dielectric film on borosilicate glass layer; use laser to scan surface of absorbing layer dielectric film; remove absorbing layer dielectric film and borosilicate glass layer; then perform thermal annealing on silicon wafer to obtain boron back field . The invention can realize the preparation of P-type monocrystalline silicon boron back field double-sided battery, and the battery performance is better.

Description

technical field [0001] The invention belongs to the technical field of solar cells, and particularly relates to a P-type single crystal silicon boron back field double-sided cell and a preparation method thereof. Background technique [0002] As a kind of clean energy, solar cells are one of the effective solutions to solve energy problems in the future. Especially after the vigorous development in recent years, its application is becoming more and more extensive, the technology is becoming more and more mature, and its power generation cost has been equal to that of coal power. [0003] As a traditional battery, the P-type monocrystalline silicon battery is usually printed on the whole surface of the aluminum paste and then sintered to form a back electric field to reduce the minority carrier recombination. However, large-area metal-aluminum paste sintering leads to large metal recombination, which limits the improvement of cell efficiency. However, boron doping directly ...

AI Technical Summary

Problems solved by technology

However, the sintering of a large area of ​​metal aluminum paste will lead to a large metal recombination, which limits the improvement of battery efficiency.

However, boron doping directly on the P-type single crystal silicon substrate requires a very high temperature, usually above 900 degrees, which will greatly damage the minority carrier lifetime in the substrate, and the silicon wafer will also introduce some other defects during the high temperature process; and currently Boron doping cannot be achieved directly on the P-type single crystal silicon substrate by laser

The back electric field structure of boron has long been proposed, but it is difficult or impractical to realize

In the prior art, boron diffusion is directly performed on the P-type silicon substrate to form a back electric field, but this will require continuous high temperature, such as above 900 degrees (usually 950-980 degrees), and 30-60 minutes of advance time. This will greatly damage the minority carrier life of the P-type silicon substrate and significantly reduce the output performance of the battery; there are also technologies that deposit boron sources on the back passivation layer of the P-type silicon substrate, and then use lasers to drive boron into the substrate In order to form a local back electric field, the applicant has found through in-depth research that the boron source cannot be penetrated directly by laser operation. No matter what parameters are changed, not only cannot penetrate, but also the boron will be blown away, so the back of boron cannot be achieved. doping

Images