Diffusion process for making solar cells

A solar cell and diffusion process technology, which is applied in the field of solar cell diffusion process, can solve the problems that the phosphorus concentration affects the uniformity of diffusion sheet resistance, reduces the concentration of phosphorus, and affects the uniformity of sheet resistance, etc.

Inactive Publication Date: 2015-09-09
JETION SOLAR HLDG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For polysilicon, reducing the concentration of more phosphorus in the second step will directly affect the uniformity of the diffusion sheet resistance
Because there are more grain boundaries on the surface of polysilicon, the difference in the absorption

Method used

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  • Diffusion process for making solar cells
  • Diffusion process for making solar cells

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Embodiment 1

[0025] The embodiment of the present invention discloses a diffusion process for making a solar cell, which includes the following steps:

[0026] 1) Control the temperature in the furnace at 840°C;

[0027] 2) At this temperature, feed 200ml / min of oxygen and 750ml / min of small nitrogen concentration, and at the same time feed 11000mL / min of large nitrogen to diffuse on the polysilicon wafer to form the first layer of diffusion thin layer, and the treatment time is 8min ;

[0028] 3) Introduce 200ml / min of oxygen and 700ml / min of small nitrogen concentration, and at the same time, inject 11000mL / min of large nitrogen, and diffuse again, and the treatment time is 11min;

[0029] 4) Stop the flow of the phosphorus source, and lower the temperature to 700°C in 25 minutes. During the entire cooling process, 2000ml / min of oxygen and 10000mL / min of nitrogen are continuously introduced to promote the impurity. Deep push, reduce the surface impurity concentration, thereby reducing ...

Embodiment 2

[0032] The embodiment of the present invention discloses a diffusion process for making a solar cell, which includes the following steps:

[0033] 1) Control the temperature in the furnace at 840°C;

[0034] 2) At this temperature, feed 500ml / min of oxygen and 1000ml / min of small nitrogen concentration, and at the same time feed 15000mL / min of large nitrogen to diffuse on the polysilicon wafer to form the first layer of diffusion thin layer, and the processing time is 8min ;

[0035] 3) Pass through 500ml / min of oxygen and 900ml / min of small nitrogen concentration, and at the same time pass through 15000mL / min of large nitrogen, and diffuse again, and the treatment time is 16 minutes;

[0036] 4) Stop the flow of the phosphorus source, and reduce the temperature to 700°C in 40 minutes. During the entire cooling process, 2500ml / min of oxygen and 15000mL / min of nitrogen are continuously introduced to promote the impurity. Deep push, reduce the surface impurity concentration, t...

Embodiment 3

[0039] The embodiment of the present invention discloses a diffusion process for making a solar cell, which includes the following steps:

[0040] 1) Control the temperature in the furnace at 840°C;

[0041] 2) At this temperature, feed 300ml / min of oxygen and 900ml / min of small nitrogen concentration, and at the same time feed 12000mL / min of large nitrogen to diffuse on the polysilicon wafer to form the first layer of diffusion thin layer, and the treatment time is 12min ;

[0042] 3) Pass 300ml / min of oxygen and 900ml / min of small nitrogen concentration, and at the same time pass through 12000mL / min of large nitrogen, and diffuse again, and the treatment time is 15min;

[0043] 4) Stop the flow of the phosphorus source, and lower the temperature to 780°C in 30 minutes. During the entire cooling process, 2300ml / min of oxygen and 12000mL / min of nitrogen are continuously introduced to promote the impurity. Deep push, reduce the surface impurity concentration, thereby reducing...

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Abstract

The invention discloses a diffusion process for making solar cells, comprising the following steps: controlling the temperature inside a furnace at 840 DEG C; feeding oxygen at 200-500ml/min and small nitrogen at 700-1000ml/min under the temperature, and feeding big nitrogen at 10000-15000mL/min, wherein the duration is 8-12min; continuing feeding oxygen at 200-500ml/min and small nitrogen at 700-900ml/min, and feeding big nitrogen at 10000-15000mL/min, wherein processing lasts 11-16min; stopping feeding phosphorus source, reducing the temperature to 700-780 DEG C in 25-40min, continuously feeding oxygen at 2000-2500ml/min and feeding big nitrogen at 10000-15000ml/min in the whole cooling process, and then taking a silicon wafer out. The problem that ohmic contact difference is caused by too much reduction of the phosphorus concentration in the diffusion process and the problem that the uniformity is poor due to the difference between crystal boundary and crystal lattice positions on polycrystalline silicon in phosphorus source absorption in the prior art are solved.

Description

technical field [0001] The invention relates to the field of manufacturing crystalline silicon solar cells, in particular to a diffusion process for solar cells. Background technique [0002] At present, the main manufacturing process of monocrystalline and polycrystalline silicon solar cells has been standardized. The main production steps are: cleaning and preparing the suede on the surface of silicon wafers, diffusion to form PN junctions, dry and wet etching to remove peripheral and back junctions, and PECVD to form anti-reflection nitriding Silicon film, screen printing to form electrodes, and sintering to form ohmic contact resistance. [0003] The PN junction formed by diffusion in the core process of solar cells has always been the heart of solar cells. There are also many researches on the process realization technology of this process. The basic diffusion steps used in production mainly include POCl 3 Phosphorus diffusion step and propulsion step. [0004] POCl ...

Claims

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Application Information

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IPC IPC(8): H01L31/18H01L21/228
CPCH01L21/228H01L31/1804Y02E10/547Y02P70/50
Inventor 钱小芳杨冬生
Owner JETION SOLAR HLDG
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