Preparation method of solar cell

Abstract

The invention discloses a preparation method of a solar cell. The method comprises the following steps: providing a plurality of polycrystalline silicon wafers for texturization; overlapping the textured silicon wafers, depositing a silicon nitride or silicon oxide masking film on the periphery of the silicon wafers, then diffusing a phosphorus doping layer on the front surface of the to-be-prepared positive electrode of the silicon wafers to form a PN junction, wherein the periphery of the silicon wafers can not form the diffusion PN junction owning to the existence of the masking film; removing the peripheral masking film and the surface phosphosilicate glass; preparing a passivation layer and an antireflection layer; and performing screen printing and sintering to form a back Ag electrode, a back Al-back surface and a front Ag electrode. In the preparation method of the solar cell provided by the invention, the masking film is formed before the impurity source diffusion used for preparing the PN junction; owning to the existence of the masking film, the periphery of the silicon wafers can not form the PN junction; and the silicon wafers after diffusion is washed with acid to remove the masking film on the periphery of the silicon wafers and the phosphosilicate glass on the diffusion surface, thus achieving the aim of replacing the etching step.

Description

technical field [0001] The invention relates to a method for manufacturing a semiconductor element, in particular to a method for preparing a solar cell, and belongs to the technical field of solar cell production. Background technique [0002] At present, the production process of conventional silicon solar cells is as follows: surface pre-cleaning, texturing to remove the damaged layer and form an anti-reflection textured structure, chemical cleaning and drying; the method of liquid source diffusion forms uniform doping at each point on the surface of the silicon wafer. Remove the peripheral PN junction and surface phospho-silicate glass formed during the diffusion process; deposit passivation and anti-reflection film on the surface; make the back electrode, back electric field and front electrode of the solar cell; sinter to form an ohmic contact, thus completing the entire battery film making process. Among them, the step of removing the peripheral PN junction formed d...

AI Technical Summary

Problems solved by technology

However, dry etching has a poor etching selectivity ratio for the underlying material, and plasma etching is often accompanied by ion bombardment and radiation, and these phenomena will cause great damage to the device.

In addition, reaction residues are often deposited on the edge of the wafer leading to particle contamination and defects

These will seriously affect the stability of etching, affect the electrical performance of the product, and cause the parallel resistance of the battery sheet to be small and the leakage current to be large.

Wet etching generally uses liquid chemical reagents (such as acid, alkali and solvent, etc.) to chemically remove the material on the surface of the silicon wafer. It has a high selectivity ratio to the underlying material and will not cause physical damage to the device, but its The chemical reaction has no direction, there will be side etching and undercutting, it is difficult to control the parameters of the etching tank to ensure its uniformity, and the treatment cost of chemical reagents is expensive, etc.

Images