A kind of preparation method of selective emitter solar cell

Abstract

The invention relates to a preparation method of a solar cell with a selective emitter. The method comprises the following steps: providing a P-type doped silicon chip, which comprises a first surface and a second surface opposite to the first surface; forming an N-type low doped layer on the first surface of the silicon chip by way of ion implantation; printing a phosphorus slurry on the N-type low doped layer according to front electrode graphical shape; performing annealing operation on the silicon chip, so that phosphor atoms in the slurry diffuse to the interior of the silicon chip, to form an N-type heavily doped layer in the silicon chip located below and close to the slurry; removing the remaining slurry; and forming a front electrode on the first surface of the silicon chip, and forming a back electrode on the second surface. According to the invention, the selective emitter is formed by way of combining phosphorous slurry printing and ion implantation, a PN junction with high quality and high uniformity can be formed, and the process is simple and easy to practice, and is easy for industrial production.

Description

technical field [0001] The invention relates to the field of solar cells, in particular to a method for preparing a selective emitter solar cell. Background technique [0002] In conventional crystalline silicon solar cells, in order to reduce the contact resistance between the electrode and the silicon wafer, it is generally required to control the sheet resistance of the surface of the silicon wafer and the area in contact with the electrode between 55Ω / □ and 70Ω / □, but At this time, the recombination on the surface of the silicon wafer will be relatively large, which will limit the conversion efficiency of the solar cell. Selective emitter solar cells can solve this problem well. [0003] Compared with the structure of conventional crystalline silicon solar cells, the selective emitter solar cell has a heavily doped region in the area where the front metal electrode contacts the silicon wafer, and a lightly doped area in the area between the front metal electrodes. Such...

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Problems solved by technology

However, these methods have certain shortcomings

Among them, the two-step diffusion method needs to go through two high-temperature annealing processes, which will cause greater damage to the surface of the silicon wafer and damage to the diffusion junction; the laser doping method will cause greater damage to the surface of the silicon wafer and cause damage to the diffusion junction. damage, which in turn affects the conversion efficiency of solar cells; while the conventional phosphorous slurry diffusion method forms a PN junction through diffusion, which will bring junction defects and make the conversion efficiency of solar cells enter a bottleneck, and the shallow junction formed by diffusion Uniformity is not easy to control

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