An oxygen-free diffusion method for crystalline silicon solar cells

A technology of solar cell and diffusion method, which is applied in the direction of circuits, photovoltaic power generation, electrical components, etc., can solve the problems of light-induced attenuation, solar cell performance degradation, and unsatisfactory performance improvement of crystalline silicon solar cells, etc., so as to be easy to remove and impossible to eliminate Controlled diffusion, improving the effect of impurity distribution

Active Publication Date: 2022-01-11
NANCHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For crystalline silicon solar cells, the combination of boron and oxygen will cause serious light-induced attenuation, and the high concentration of oxygen itself will form various types of defects, resulting in a decline in solar cell performance
Therefore, various types of aerobic diffusion are not ideal for improving the performance of crystalline silicon solar cells.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] For n-type polysilicon solar cells, remove the sacrificial layer and polish the surface of the silicon wafer, put it into the hot wire chemical vapor deposition chamber after cleaning, and deposit a layer of heavily boron-doped non Crystalline silicon film with a thickness of 50nm; then put the silicon wafer into a tubular high-temperature furnace, use nitrogen as a protective gas, and diffuse at 980°C for 60 minutes; cool down to 600°C and take out the silicon wafer. Put the silicon wafer into the hot wire chemical vapor deposition chamber again, and deposit a layer of heavily phosphorus-doped amorphous silicon film on the surface where the back electric field layer needs to be prepared, with a thickness of 20nm; then put the silicon wafer into the tubular In a high-temperature furnace, use nitrogen as a protective gas, diffuse at 830°C for 20 minutes; then lower the furnace temperature to 790°C, and use nitrogen-oxygen mixture with 20% oxygen content as a reaction gas,...

Embodiment 2

[0021] For n-type monocrystalline silicon solar cells, remove the loss layer and texture the surface of the silicon wafer, put it into the plasma-enhanced chemical vapor deposition chamber after cleaning, and deposit a layer of heavily doped silicon on the surface of the silicon wafer that needs to be used as the emitter. Boron-doped amorphous silicon film with a thickness of 40nm; then put the silicon wafer into a tube-type high-temperature furnace, use nitrogen with a hydrogen content of 2% as a protective gas, and diffuse at 1050°C for 40 minutes; then the furnace temperature Lowered to 800°C, annealed for 60 minutes with 10% oxygen content of nitrogen-oxygen mixture as the reaction gas. Lower the temperature to 600°C and take out the silicon wafer. At this time, there are oxide layers on both sides of the silicon wafer. The oxide layer on both sides was removed with hydrofluoric acid. For the deposition and diffusion process of the source layer of the heavily doped layer,...

Embodiment 3

[0023] For p-type monocrystalline silicon solar cells, remove the loss layer and texture the surface of the silicon wafer, put it into the plasma-enhanced chemical vapor deposition chamber after cleaning, and deposit a layer of heavily doped silicon on the surface of the silicon wafer that needs to be used as the emitter. Phosphorous amorphous silicon film with a thickness of 20nm; then put the silicon wafer into a tube-type high-temperature furnace, use argon as a protective gas, and diffuse at 820°C for 30 minutes; then lower the furnace temperature to 700°C, Nitrogen-oxygen mixed gas with 10% oxygen content was used as the reaction gas, and annealed for 200 min. Lower the temperature to 600°C and take out the silicon wafer. At this time, there are oxide layers on both sides of the silicon wafer. The oxide layer on both sides was removed with hydrofluoric acid. For the deposition and diffusion process of the source layer of the heavily doped layer, the square resistance and...

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PUM

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Abstract

An oxygen-free diffusion method for crystalline silicon solar cells, comprising: depositing a silicon wafer whose surface does not contain oxygen and a source layer film containing high-concentration dopant atoms, in a high-temperature furnace with an oxygen-free atmosphere at 810‑1050 Diffusion is carried out in the temperature range of ℃; after the diffusion is completed, the furnace temperature is lowered to 700-800°C, and an atmosphere with an oxygen volume concentration >2% is introduced, and annealing treatment is performed for 20-200min. The invention eliminates the possibility of oxygen entering the silicon wafer through the diffusion step, and can improve the impurity distribution state in the silicon wafer and the minority carrier lifetime of the silicon wafer; prevents the diffusion of oxygen to the silicon wafer and the uncontrollable elements in the doped layer diffusion. The invention is suitable for preparing p-type crystalline silicon diffusion layer and n-type crystalline silicon diffusion layer on n-type crystalline silicon chip, and also suitable for preparing n-type crystalline silicon diffusion layer and p-type crystalline silicon diffusion layer on p-type crystalline silicon chip. It is not only suitable for preparing monocrystalline silicon solar cells, but also suitable for preparing polycrystalline silicon solar cells.

Description

technical field [0001] The invention belongs to the field of solar cells and semiconductor devices. The invention relates to a preparation method of a solar cell. Background technique [0002] For crystalline silicon solar cells with a pn homojunction structure, the diffusion method is by far the most commonly used method for preparing heavily doped n-type crystalline silicon layers or p-type crystalline silicon layers. [0003] The n-type crystalline silicon thin film prepared by the diffusion method is generally used as the emitter of the p-type crystalline silicon solar cell, or as the back electric field of the n-type crystalline silicon solar cell. This method generally uses phosphorus oxychloride as the dopant source, and the dopant source and oxygen are passed into the diffusion furnace with nitrogen as the carrier gas, and are reacted and deposited on the surface of the silicon wafer at a temperature of about 800-900 ° C to form phosphorus silicon. Glass, the phosp...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L21/225H01L31/068H01L31/18H01L31/048
CPCH01L31/068H01L31/1804H01L21/2252Y02E10/546Y02E10/547Y02P70/50
Inventor 黄海宾周浪
Owner NANCHANG UNIV
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