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PERC cell back side passivation technology

A backside passivation and battery technology, which is applied in the field of solar cells, can solve the problems of poor matching between aluminum oxide and silicon of the backside passivation layer, poor surface passivation effect, and increased EL degradation, so as to improve field passivation. effect, increase the passivation effect, improve the effect of anti-PID performance

Inactive Publication Date: 2017-07-28
TONGWEI SOLAR HEFEI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The technical problem to be solved by the present invention is that in the prior art, the matching between aluminum oxide and silicon in the back passivation layer is not very good, and the surface passivation effect is not good. Aluminum oxide will amplify some back surface defects, thereby causing increased EL degradation, A The problem of grade rate drop

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  • PERC cell back side passivation technology
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  • PERC cell back side passivation technology

Examples

Experimental program
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Effect test

Embodiment 1

[0033] A passivation process for the back of PERC cells, including texturing, diffusion, etching and back polishing, followed by hot air drying of silicon wafers, turning the silicon wafers 180° so that the back of the silicon wafers face up, and ozone treatment to form SiO on the back 2 film, the front side is oxidized, the back is plated with a passivation film, and the front side is plated with a passivation film; the front side is oxidized to be annealed to form SiO 2 membrane.

[0034]Specifically, 1. Texturing: use a chemical solution to etch the surface of the crystalline silicon wafer to form a suede surface with a light-trapping effect. The PN junction is formed on the silicon wafer at the bottom, and at present, the liquid source diffusion method of phosphorus oxychloride is mainly used.

[0035] 3. Etching and back polishing: acid bath (HF / HNO 3 / H 2 SO 4 ) etch to remove the edge PN junction and polish the backside - alkali bath (KOH) to neutralize the acid and...

Embodiment 2

[0044] A passivation process for the back of PERC cells, including texturing, diffusion, etching and back polishing, followed by hot air drying of silicon wafers, turning the silicon wafers 180° so that the back of the silicon wafers face up, and ozone treatment to form SiO on the back 2 film, the front side is oxidized, the back is plated with a passivation film, and the front side is plated with a passivation film; the front side is oxidized to be annealed to form SiO 2 membrane.

[0045] Specifically, 1. Texturing: use a chemical solution to etch the surface of the crystalline silicon wafer to form a surface textured surface with a light-trapping effect

[0046] 2. Diffusion: Put the crystalline silicon wafer into the diffusion furnace, and use the diffusion method to form a PN junction on the silicon wafer of the P-type substrate. At present, it is mainly the phosphorus oxychloride liquid source diffusion method.

[0047] 3. Etching and back polishing: acid bath (HF / HNO ...

Embodiment 3

[0056] A method for preparing a PERC cell, comprising: 1. Texturing: corroding the surface of a crystalline silicon wafer with a chemical solution to form a surface textured surface with a light-trapping effect

[0057] 2. Diffusion: Put the crystalline silicon wafer into the diffusion furnace, and use the diffusion method to form a PN junction on the silicon wafer of the P-type substrate. At present, it is mainly the phosphorus oxychloride liquid source diffusion method.

[0058] 3. Etching and back polishing: acid bath (HF / HNO 3 / H 2 SO 4 ) etch to remove the edge PN junction and polish the backside - alkali bath (KOH) to neutralize the acid and remove the porous silicon - acid bath (HF / HCL) to remove the front phosphosilicate glass, dry the silicon wafer with hot air, and turn the film with the turning machine. Ozone treatment on the back.

[0059] 4. Annealing treatment: Put the silicon wafer into the annealing furnace, pass a certain amount of oxygen during annealing, ...

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Abstract

The invention belongs to the solar energy cell field and more particularly, to a PERC cell back side passivation technology, comprising: texturing, diffusing, etching and backside polishing, followed by silicon wafer baking in hot wind; turning the backside of the silicon wafer upward by 180 degrees for ozone treatment to develop the front side oxidation treatment of the SiO2 film with the backside plated by a passivation film and the front side plated by a passivation film wherein the front side oxidation treatment is annealing treatment thermal oxidation method to develop the SiO2 film. According to the PERC cell back side passivation technology proposed by the invention, a silicon oxide film is developed whose backside thickness is even and the SiO2 and Si match better, effectively reducing the interface state density of the Si surface and increasing the field passivation effect of the AI203. The probability of EL degrading is reduced while the A-grade qualified rate is increased. In addition to that, the manufacturing cost for PERC cells is reduced and the cell performance is increased, therefore, making the technology of great significance in the energy aspect.

Description

technical field [0001] The invention belongs to the field of solar cells, and in particular relates to a back passivation process of PERC cells. Background technique [0002] PERC technology, that is, passivated emitter back contact, can greatly reduce the electrical recombination rate of the back surface by forming a passivation layer on the back of the solar cell, form a good internal optical back reflection mechanism, and increase the open circuit voltage and short circuit current of the battery, thereby improving The conversion efficiency of the battery. [0003] PERC solar cell has the advantages of simple process, low cost, and high compatibility with existing cell production lines. It is a newly developed high-efficiency solar cell. It has received extensive attention from the industry and is expected to become the mainstream direction of high-efficiency solar cells in the future. . [0004] For the production of conventional silicon solar cells, the production step...

Claims

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Application Information

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IPC IPC(8): H01L31/18H01L31/068H01L31/0216
CPCH01L31/02167H01L31/068H01L31/1868Y02E10/547Y02P70/50
Inventor 闫涛张冠纶吴俊旻常青扈静
Owner TONGWEI SOLAR HEFEI
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