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P-type monocrystalline silicon boron back surface field double-sided battery and preparation method thereof

A monocrystalline silicon boron, double-sided battery technology, applied in the field of solar cells, can solve the problems of lower battery output performance, limit the improvement of battery efficiency, and failure to enter, so as to achieve good battery electrical performance, reduce metal recombination, and process simple effect

Active Publication Date: 2020-10-09
JA SOLAR TECH YANGZHOU
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the sintering of a large area of ​​metal aluminum paste will lead to a large metal recombination, which limits the improvement of battery efficiency.
However, boron doping directly on the P-type single crystal silicon substrate requires a very high temperature, usually above 900 degrees, which will greatly damage the minority carrier lifetime in the substrate, and the silicon wafer will also introduce some other defects during the high temperature process; and currently Boron doping cannot be achieved directly on the P-type single crystal silicon substrate by laser
The back electric field structure of boron has long been proposed, but it is difficult or impractical to realize
In the prior art, boron diffusion is directly performed on the P-type silicon substrate to form a back electric field, but this will require continuous high temperature, such as above 900 degrees (usually 950-980 degrees), and 30-60 minutes of advance time. This will greatly damage the minority carrier life of the P-type silicon substrate and significantly reduce the output performance of the battery; there are also technologies that deposit boron sources on the back passivation layer of the P-type silicon substrate, and then use lasers to drive boron into the substrate In order to form a local back electric field, the applicant has found through in-depth research that the boron source cannot be penetrated directly by laser operation. No matter what parameters are changed, not only cannot penetrate, but also the boron will be blown away, so the back of boron cannot be achieved. doping

Method used

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  • P-type monocrystalline silicon boron back surface field double-sided battery and preparation method thereof
  • P-type monocrystalline silicon boron back surface field double-sided battery and preparation method thereof
  • P-type monocrystalline silicon boron back surface field double-sided battery and preparation method thereof

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preparation example Construction

[0041] The invention discloses a preparation method of a P-type single crystal silicon boron back field double-sided battery, comprising the following steps:

[0042] S1. Provide a P-type silicon substrate 1, and clean and texture the P-type silicon substrate 1;

[0043] S2, performing phosphorus diffusion on the textured surface of the front side of the P-type silicon substrate to form a phosphorus expansion area 2;

[0044] S3. Wet etching the back of the P-type silicon substrate to remove side junctions and partial back junctions;

[0045] S4, after the wet etching on the back of the P-type silicon substrate is completed, depositing a borosilicate glass layer 3 thereon;

[0046] S5, depositing the absorbing layer dielectric film 4 on the borosilicate glass layer 3;

[0047] S6, scanning the surface of the absorbing layer dielectric film 4 with a laser;

[0048] S7, removing the dielectric film of the absorbing layer and the borosilicate glass layer (i.e. BSG); then perfo...

Embodiment 1

[0073] This embodiment provides a P-type monocrystalline silicon boron back field double-sided cell, such as figure 2 As shown, including a P-type silicon substrate 1, the front of the P-type silicon substrate 1 is sequentially provided with a phosphorus diffusion region 2, an anti-reflection film 5, and a front electrode 7 along a direction away from the P-type silicon substrate 1; Boron back field 6, anti-reflection film 5 and back electrode 8 are sequentially provided along the direction away from P-type silicon substrate 1; wherein, the thickness of boron back field 6 is 400nm, see image 3 .

[0074] The P-type monocrystalline silicon-boron back-field double-sided cell of this example is prepared by the following method:

[0075] Step 101, select a P-type single crystal silicon substrate with a certain thickness (150-200 μm) and resistivity (1-3 ohm*cm), and clean and texture the P-type silicon substrate;

[0076] Step 102, perform phosphorus diffusion on the textured ...

Embodiment 2

[0086] This embodiment provides a P-type monocrystalline silicon boron back field double-sided cell, such as figure 2 As shown, including a P-type silicon substrate 1, the front of the P-type silicon substrate 1 is sequentially provided with a phosphorus diffusion region 2, an anti-reflection film 5, and a front electrode 7 along a direction away from the P-type silicon substrate 1; A boron back field 6, an antireflection film 5 and a back electrode 8 are sequentially provided along the direction away from the P-type silicon substrate 1; wherein, the thickness of the boron back field 6 is 350nm, see Figure 4 .

[0087] The preparation method of the P-type monocrystalline silicon-boron back-field double-sided cell in this embodiment is the same as that in Embodiment 1, and will not be repeated here. The difference lies in:

[0088] In step 105, a silicon oxynitride (SiON) film is deposited on the above-mentioned borosilicate glass layer by plasma enhanced chemical vapor depo...

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Abstract

The invention discloses a P-type monocrystalline silicon boron back surface field double-sided battery and a preparation method thereof. The invention belongs to the technical field of solar cells, and solves the problems that boron doping cannot be realized on a P-type monocrystalline silicon substrate by adopting laser and the like in the prior art. The invention provides a preparation method ofthe P-type monocrystalline silicon boron back surface field double-sided battery, which comprises the following steps: providing a P-type silicon substrate, and cleaning and texturing the P-type silicon substrate; performing phosphorus diffusion on the texturing surface of the front surface of the P-type silicon substrate to form a phosphorus diffusion region; carrying out wet etching on the backsurface of the P-type silicon substrate to remove edge junctions and part of back junctions; depositing a borosilicate glass layer on the P-type silicon substrate after wet etching of the back surface of the P-type silicon substrate is completed; depositing an absorption layer dielectric film on the borosilicate glass layer; carrying out surface scanning on the absorption layer dielectric film byusing laser; removing the absorption layer dielectric film and the borosilicate glass layer; and then carrying out thermal annealing on the silicon wafer to obtain a boron back surface field. According to the invention, the preparation of the P-type monocrystalline silicon boron back surface field double-sided battery can be realized, and the battery performance is better.

Description

technical field [0001] The invention belongs to the technical field of solar cells, and in particular relates to a P-type single-crystal silicon-boron back-field double-sided cell and a preparation method thereof. Background technique [0002] As a clean energy source, solar cells are one of the effective solutions to energy problems in the future. Especially after vigorous development in recent years, its application is becoming more and more extensive, the technology is becoming more and more mature, and its power generation cost is equivalent to that of coal power. [0003] As a traditional battery, P-type monocrystalline silicon cells are usually printed with aluminum paste on the entire surface and then sintered to form a back electric field to reduce minority carrier recombination. However, the sintering of a large area of ​​metal aluminum paste will lead to a large metal recombination, which limits the improvement of battery efficiency. However, boron doping directl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L31/18H01L31/0216H01L31/068
CPCH01L31/02167H01L31/02168H01L31/1804H01L31/186H01L31/1868H01L31/1864H01L31/0684H01L31/0682Y02E10/547Y02P70/50
Inventor 曹兵
Owner JA SOLAR TECH YANGZHOU