Diffusion technique for silicon solar cell emitter

A silicon solar cell and diffusion process technology, applied in the field of diffusion process, can solve the problems of solar cell short-wave degradation, device efficiency reduction, solar cell short-circuit current loss, etc., achieve simple process and reduce the effect of Auger recombination

Inactive Publication Date: 2009-04-08
INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the high doping concentration on the surface, the recombination process of photogenerated carriers in the emitter is dominated by Auger recombination, which cau

Method used

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  • Diffusion technique for silicon solar cell emitter
  • Diffusion technique for silicon solar cell emitter
  • Diffusion technique for silicon solar cell emitter

Examples

Experimental program
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Effect test

Embodiment 1

[0031] Use P-type monocrystalline silicon or polycrystalline silicon wafers, go through conventional surface texture, cleaning, drying and other processes, and then diffuse. The diffusion steps are as follows:

[0032] (1) The temperature is 820°C, 18 liters / min of protective nitrogen gas is introduced, and the quartz boat on which the silicon wafer is placed is slowly pushed into the diffusion furnace.

[0033] (2) After the quartz boat is pushed into a proper position, the temperature is raised from 820° C. to 840° C., and 4 liters / minute of oxygen is introduced for 5 minutes.

[0034] (3) At a temperature of 840°C, perform pre-diffusion: 1.8 liters / min of POCl is passed through 3 The source of nitrogen, the oxygen flow rate was changed to 3 L / min, and the time was 45 minutes.

[0035] (4) Carry out propulsive diffusion: stop carrying POCl 3 Source nitrogen and oxygen are introduced, the temperature rises from 840°C to 860°C for 8 minutes, and stabilizes at 860°C for 10 m...

Embodiment 2

[0040] Use P-type monocrystalline silicon or polycrystalline silicon wafers, go through conventional surface texture, cleaning, drying and other processes, and then diffuse.

[0041] (1) The temperature is 800°C, 18 liters / min of protective nitrogen gas is introduced, and the quartz boat on which the silicon wafer is placed is slowly pushed into the diffusion furnace.

[0042] (2) At 800° C., 4 liters / minute of oxygen was introduced for 5 minutes.

[0043] (3) At a temperature of 800°C, carry out a pre-diffusion process: feed 1.8 liters / minute to carry POCl 3 The source of nitrogen, the oxygen flow rate was changed to 3.0 L / min for 10 minutes.

[0044] (4) Carry out propulsive diffusion: stop carrying POCl 3 Source nitrogen and oxygen are introduced, the temperature rises from 800°C to 830°C for 5 minutes, and stabilizes at 830°C for 35 minutes. The total propulsion diffusion time was 40 minutes.

[0045] (5) After the diffusion is finished, cool down to the initial furnac...

Embodiment 3

[0049] Use P-type monocrystalline silicon or polycrystalline silicon wafers, go through conventional surface texture, cleaning, drying and other processes, and then diffuse.

[0050] (1) The temperature is 800°C, 18 liters / min of protective nitrogen gas is introduced, and the quartz boat on which the silicon wafer is placed is slowly pushed into the diffusion furnace.

[0051] (2) At 800° C., 4 liters / minute of oxygen was introduced for 5 minutes.

[0052] (3) At a temperature of 800°C, carry out a pre-diffusion process: 0.8 liters / min of POCl is introduced 3 The source of nitrogen, the flow rate of oxygen was changed to 1.2 L / min for 10 minutes.

[0053] (4) Carry out propulsive diffusion: stop carrying POCl 3 Source nitrogen and oxygen are introduced, the temperature rises from 800°C to 830°C for 5 minutes, and stabilizes at 830°C for 15 minutes. The total propulsion diffusion time was 20 minutes.

[0054] (5) After the diffusion is finished, cool down to the initial fur...

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Abstract

The invention discloses a diffusion technique of a silicon solar cell emitter. The technique comprises the following steps: (1) low-temperature prediffussion is carried out: a silicon wafer is placed into a diffusion furnace and inlet with protective nitrogen as well as nitrogen and oxygen carrying a POCl3 source at the diffusion temperature of 800-840 DEG C for 10-50 minutes; (2) promoting diffusion at higher temperature: the nitrogen and the oxygen carrying a phosphorus source are cut off and the diffusion temperature is raised to 820-860 DEG C to promote the diffusion of phosphorus atoms in the course of rising and stabilizing the temperature for 10-40 minutes; and (3) the diffusion furnace is cooled and the silicon wafer is taken out. By adopting the technique, a moderate surface doping concentration and a thicker emitter doping curve can be achieved, therefore, the compound effect caused by the high surface doping concentration of the emitter is reduced, and short circuit current of the solar cell is enhanced. The technique can realize a broader range of square resistance distribution, and obtain a square resistance value meeting the contact with a metal electrode.

Description

technical field [0001] The invention relates to a diffusion process, in particular to an emitter diffusion process applied to crystalline silicon solar cells. Background technique [0002] Diffusion is a very useful step in the semiconductor manufacturing process. It is a process of moving atoms or molecules from a high-concentration area to a low-concentration area at high temperature. The purpose is to control the concentration, uniformity and repeatability of impurities. Generally, there are two ways for impurities to diffuse at high temperature in semiconductors: constant surface concentration and constant total doping concentration. In the first case, the impurity is usually a gas-phase source, and the atoms are transported from the source vapor to the silicon surface and diffuse into the silicon wafer. During the entire diffusion period, since there is always a gas phase source, the source vapor maintains a constant surface concentration; another method of doping impu...

Claims

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Application Information

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IPC IPC(8): H01L31/18
CPCY02P70/50
Inventor 周春兰王文静
Owner INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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