Boron diffusion method for N-type crystalline silica solar cell

A technology of solar cells and diffusion methods, applied in the directions of crystal growth, diffusion/doping, chemical instruments and methods, etc., can solve the problems of reducing the photoelectric conversion efficiency of the battery, increasing the series resistance of the battery, and reducing the surface boron concentration, and avoiding the The difficulty of metallization and sintering, the effect of increasing the surface boron concentration and the simple preparation method

Active Publication Date: 2012-08-29
CSI CELLS CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This may be due to the fact that the current diffusion process takes a long time to advance, resulting in the continuous diffusion of boron on the silicon surface into the body, resulting in a decrease in the surface boron concentration, which will bring great difficulties to the subsequent metallization sintering. Once the metallization sintering process Metal electrodes cannot form a good ohmic contact with the surface of the silicon wafer, which will lead to an increase in the series resistance of the battery, thereby reducing the photoelectric conversion efficiency of the battery

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] A method for boron diffusion of N-type crystalline silicon solar cells. A group of N-type monocrystalline silicon wafers (50 pieces) after texturing and cleaning are processed as follows:

[0019] (1) Heat treatment in a nitrogen atmosphere at 800°C for 5 minutes, with a nitrogen flow rate of 5L / min;

[0020] (2) Diffusion with boron source at 1000°C for 20 minutes, nitrogen flow rate is 13 L / min, oxygen flow rate is 0.5 L / min, BBr 3 Flow 1.5L / min;

[0021] (3) Continue to cool down to 760°C to complete the diffusion process; the nitrogen flow rate is 8 L / min.

[0022] After the diffusion is completed, 5 silicon wafers are extracted from each uniform position in the silicon wafers obtained in the foregoing embodiments, and the electrochemical capacitance voltage method is used to test the sheet resistance, and the following surface boron concentration test data are obtained:

[0023] Embodiment one:

[0024] Location Surface boron concentration (cm -3 ) ...

Embodiment 2

[0027] A method for boron diffusion of an N-type crystalline silicon solar cell, comprising the following steps of treating a group of N-type monocrystalline silicon wafers (50 pieces) after texturing and cleaning as follows:

[0028] (1) Heat treatment in a nitrogen atmosphere at 850°C for 5 minutes, with a nitrogen flow rate of 6L / min;

[0029] (2) Diffusion with boron source at 1050°C for 20 minutes, nitrogen flow at 15 L / min, oxygen flow at 0.6 L / min, BBr 3 Flow 1.6L / min;

[0030] (3) Continue to cool down to 800°C to complete the diffusion process; the nitrogen flow rate is 6 L / min.

[0031] After the diffusion was completed, 5 silicon wafers were taken from a uniform position to test the boron concentration on the surface to obtain the following data:

[0032] Location Surface boron concentration (cm -3 ) 5 4.4×10 20 13 4.6×10 20 26 4.8×10 20 35 4.5×10 20 46 4.3×10 20

[0033] As can be seen from the above two examples, th...

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Abstract

The invention discloses a boron diffusion method for N-type crystalline silica solar cell. The method comprises the following steps: carrying out an etching wash treatment on a N-type silicon chip, carrying out a heat treatment on the N-type silicon chip in nitrogen which followed by heating up and access of a boron source to start boron diffusion; carrying out a cooling treatment on the silicon chip and introducing nitrogen gas to complete the diffusion process. According to the diffusion method in the invention, the boron concentration of the N-type silicon chip is substantially improved, the difficulty of subsequent metallization sintering is avoided, which facilitating the improvement of the electrical performance of the whole N-type crystalline silica solar cell.

Description

technical field [0001] The invention relates to a diffusion junction process for N-type crystalline silicon solar cells, in particular to a boron diffusion method for N-type crystalline silicon solar cells, and belongs to the field of crystalline silicon solar cell manufacturing. Background technique [0002] Conventional fossil fuels are being exhausted day by day. Among the existing sustainable energy sources, solar energy is undoubtedly the cleanest, most common and most potential alternative energy source. At present, among all solar cells, silicon solar cells are one of the solar cells that have been widely commercialized. This is due to the extremely abundant reserves of silicon materials in the earth's crust. With excellent electrical and mechanical properties, silicon solar cells occupy an important position in the field of photovoltaics. Therefore, developing cost-effective silicon solar cells has become one of the main research directions of photovoltaic companies...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B31/08
Inventor 杨智王栩生章灵军
Owner CSI CELLS CO LTD
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