Method for manufacturing rear side local contact silicon solar cell

Abstract

The invention provides a method for manufacturing a rear side local contact silicon solar cell. In the prior art, local contact and a silicon wafer cannot form good ohmic contact, or the electrical performance of the silicon wafer, which is provided with local contact but no passivation layer at the rear side, is reduced because of heat treatment is carried out on the silicon wafer. The method provided by the invention comprises the steps of: firstly, texturing and cleaning a corresponding silicon wafer of the silicon solar cell, forming a PN junction at the front side of the silicon wafer through diffusion, thereafter removing the PN junction outside a front side region of the silicon wafer through etching, then forming an antireflection film at the front side of the silicon wafer and forming the same type of local contact as the silicon wafer in the local region of the rear side, thereafter forming a passivation layer at the rear side, then sintering the silicon wafer so as to enable the local contact to be heavily doped into the silicon wafer to form a heavily doped region, and finally forming a front side electrode and a rear side electrode at the front side and the rear side of the silicon wafer respectively. The method provided by the invention can improve the ohmic contact between the local contact and the silicon wafer, and can reduce damages produced by heat treatment in the absent of the passivation layer.

Description

technical field [0001] The invention relates to a silicon solar cell manufacturing process, in particular to a method for manufacturing a silicon solar cell with partial back contact. Background technique [0002] A silicon solar cell is essentially a PN junction device. The photo-generated carriers generated by light are driven to both sides of the PN junction through the electric field of the PN junction to form a photo-generated current, thereby achieving the effect of photoelectric conversion. In order to reduce the recombination of photogenerated carriers and improve the electrical performance of silicon solar cells, structures or measures to reduce the recombination mechanism are added in the silicon wafer body and surface. In the body, high-purity, low-defect, low-oxygen silicon single crystal or polycrystalline materials should be selected; on the back, the back electric field is formed by heavily doping the same type of material as the silicon wafer, and the drift s...

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Problems solved by technology

[0006] The above-mentioned method of corroding a local area of ​​the passivation layer with a corrosive slurry to make a local contact has the problems that the manufacturing process is complicated and it is difficult to form a good ohmic contact between the local contact and the silicon wafer due to reasons such as poor corrosion; and The above-mentioned method of printing paste directly on the local area of ​​the passivation layer on the back of the silicon wafer and sintering to form a local contact is also difficult to form a good ohmic contact because it is difficult to accurately burn through the passivation layer

[0007] In order to solve the above-mentioned problem that it is difficult to form a good ohmic contact between the local contact and the silicon wafer, the existing technology also forms a local contact on the local area of ​​the back of the silicon wafer by means of screen printing before forming a passivation layer on the back, Then through sintering, the local contact is heavily doped into the silicon wafer to form a heavily doped back field, and then a passivation layer is formed

This method can form a good ohmic contact between the silicon wafer and the back contact, but there is no passivation layer on the back of the silicon wafer during the sintering process, and the high temperature of sintering is likely to cause the silicon wafer to be contaminated by impurities, thereby reducing the electrical capacity of the silicon solar cell. performance

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