Preparation method of solar cell for reutilizing diffusion oxide layer

A solar cell and oxide layer technology, which is applied in the manufacture of circuits, electrical components, and final products, can solve the problems of high boron diffusion temperature, difficult removal, deep back junctions, etc.

CN102364698AInactive Publication Date: 2012-02-29TRINASOLAR CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2012-02-29
Estimated Expiration
Not applicable · inactive patent
Patent Text Reader

Abstract

The invention relates to a preparation method of a solar cell for reutilizing a diffusion oxide layer. The method comprises the following steps of: not removing a silicon oxide layer (such as BSG (Boron Silicate Glass) and PSG (Phosphosilicate Glass)) formed by diffusion on a front face immediately but plating a layer of film on the oxide layer after a diffusion process is completed to form a double-layer film for serving as a mask for quickly removing back face junctions subsequently and for use in a procedure for making a back face electric field by back diffusion; and removing the film and the silicon oxide layer on the front face, and a silicon oxide layer on the back face together with hydrofluoric acid in a post cleaning procedure. Due to the adoption of the method, back junctions formed by diffusion can be removed quickly, the production process flow is optimized, the cell producing and manufacturing time is shortened greatly, and mass production is available.
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Description

technical field

[0001] The invention relates to a production process of a high-efficiency single-crystal silicon solar cell, in particular to a production process of a high-efficiency single-crystal silicon solar cell. Background technique

[0002] Compared with P-type batteries, N-type batteries have the characteristics of less efficiency loss due to light-induced attenuation, and are more resistant to pollution by metal impurities. Existing high-efficiency cells are all realized on N-type substrates. The boron diffusion temperature of N-type B-junction cells is high, the time is long, and the depth of the formed back junction is relatively deep. It is difficult to remove it in the post-cleaning steps of ordinary production lines. At the same time, in the existing silicon cell production process, immediately remove the phosphosilicate glass or borosilicate glass and cut the edge after the diffusion, and when phosphorus diffusion or Peng diffusion is required to control the...

Examples

Embodiment 1

[0019] Select an N-type Czochralski monocrystalline silicon wafer with a doping concentration of 5Ωcm.

[0020] 1. Clean the silicon wafer, remove the damaged layer, and make the surface alkali-textured;

[0021] 2. Boron diffuses to form a P-N junction with a square resistance of 70ohm / Sq;

[0022] 3. While retaining the BSG (thickness 100nm), deposit a SiNx thin film on the front side by PECVD with a thickness of about 90nm.

[0023] 4. 20% KOH to remove the back knot, the time is 30s.

[0024] 5. Phosphorus diffuses to form a back field, and the square resistance is 30ohm / sq;

[0025] 6. Clean with 5% HF to remove the mask layer on the front side and the PSG on the back side.

[0026] 7. Plasma etching to remove edges.

[0027] 8. Al2O330nm deposited by PECVD on the front side.

[0028] 9. Anti-reflection coating SiNx 40nm deposited by PECVD on the front side.

[0029] 10. Deposit SiNx 90nm on the back side by PECVD.

[0030] 11. Printed AgAl grid lines on the front ...

Embodiment 2

[0036] Select a P-type Czochralski monocrystalline silicon wafer with a doping concentration of 1Ωcm.

[0037] 1. Clean the silicon wafer, remove the damaged layer, and make the surface alkali-textured;

[0038] 2. Phosphorus diffuses to form a P-N junction, with a square resistance of 70ohm / Sq;

[0039] 3. Preserve PSG (thickness 30nm) while depositing SiO on the front side by PECVD 2 thin film with a thickness of approximately 150 nm.

[0040] 4. 20% KOH to remove the back knot, the time is 30s.

[0041] 5. Boron diffusion forms a back field, and the square resistance is 30ohm / sq;

[0042] 6. Wash with 5% HF to remove the mask layer on the front side and the BSG on the back side.

[0043] 7. Plasma etching to remove edges.

[0044] 8. The front PECVD deposits SiNx90nm.

[0045] 9. Al2O330nm deposited by PECVD on the back;

[0046] 10. Deposit SiNx50nm on the back side by PECVD.

[0047] 11. Ag grid lines are printed on the front side;

[0048] 12. Drying;

[0049] ...