Passivation process for back of crystalline silicon solar cell and structure of back-passivated crystalline silicon solar cell

Abstract

The invention relates to a passivation process for a back of a crystalline silicon solar cell and a structure of a back-passivated crystalline silicon solar cell. The passivation process comprises: firstly, based on silicon nitride used as a mask on the back of a P-type silicon wafer, forming holes on the mask, then carrying out B diffusion to form heavy doping at the hole positions, washing away the silicon nitride mask, depositing a laminated film of aluminum oxide and silicon nitride, forming back contact patterns on the back of a cell, and manufacturing an aluminum electrode on the back of the cell. The invention has the beneficial effects that: the back-passivated solar cell has the following two characteristics: (1) a high-doped heavy-diffusion region is formed at the back contact and near position thereof of the cell, and the high-doped heavy-diffusion region is in good ohmic contact with the plated aluminum electrode, thus the series resistance of the cell is reduced; and (2) by annealing aluminum oxide, the back surface can be well passivated and the surface compounding rate is reduced, and silicon nitride has an action of protecting aluminum oxide, thus the destroy of aluminum oxide passivation effect in subsequent sputtering or evaporation process is avoided.

Description

technical field [0001] The invention relates to a rear passivation process and structure of a crystalline silicon solar cell. Background technique [0002] Traditional solar cell fabrication methods, such as figure 1 As shown, the process flow is cleaning texture, diffusion, edge etching and PSG removal, PECVD SiNx film plating, screen printing, sintering and electrical performance testing. This traditional process determines that the efficiency of solar cells cannot be greatly improved, and the back passivation can reduce the surface recombination rate of the battery, which can greatly improve the efficiency. The existing methods of back passivation batteries are: 1. Backside plating Alumina is passivated, holes are opened using a corrosive paste, and then aluminum paste is printed for sintering. 2. The back is plated with silicon oxide for passivation, using corrosive paste to open holes, and then printing aluminum paste for sintering. 3. The back is plated with silicon...

AI Technical Summary

Problems solved by technology

[0003] These processes of depositing dielectric films, opening holes with corrosive paste, and printing aluminum paste for sintering all have a common problem. The sintering process often destroys the passivation effect.

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