Solar-grade Czochralski (CZ) silicon single crystal thermal donor control process

A solar-grade, thermal donor technology, applied in the direction of single crystal growth, crystal growth, chemical instruments and methods, etc., can solve the problems of unfavorable solar-grade single crystal silicon wafers, reduced quality, high resistivity, etc., to achieve obvious control of thermal donors, The effect of significant cost reduction and simple process method

Inactive Publication Date: 2011-03-30
王正园
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Problems solved by technology

Therefore, the thermal donor of oxygen will directly affect the resistivity of the head of the solar-grade monocrystalline rod, making the resistivity higher and even turning into N-type, which is extremely unfavorable to the production of solar-grade monocrystalline silicon wafers, which leads to the rear end in order to reduce the resistance The annealing process is used to reduce the rate, and the annealing process further affects the yield of silicon wafers and the efficiency of cells after being made into cells, which increases production costs and reduces quality.

Method used

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Embodiment Construction

[0016] The specific process is introduced below:

[0017] 1. Preparation before production

[0018] 1. Feeding is according to the specified feeding amount of CZ single crystal furnace.

[0019] 2. The size of the opening of the guide tube near the liquid surface: the diameter of the silicon rod ≥ 5:3.

[0020] 3. When charging, the primary silicon is kept away from the crucible wall.

[0021] 2. Production process

[0022] 1. Production of whole rods;

[0023] 2. The highest chemical power: after 3 hours of equal diameter, the power is ≤8:5;

[0024] 3. After the chemical is finished, slag hanging, doping, (or pre-mixing) is carried out, and the volatilization process is carried out after completion;

[0025] 4. The volatilization time is 3-5 hours. Reduce the power to slightly higher than the seeding power (3-5KW is better), the air pressure is less than 800Pa (300-500Pa is better), the crucible rotation is less than 5r / min (1r / min is better), The height of the guide ...

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PUM

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Abstract

The invention relates to a solar-grade Czochralski (CZ) silicon single crystal thermal donor control process. The technical problems to be solved are to control the thermal donor concentration at the head of a CZ silicon single crystal and reduce or avoid silicon wafers needing annealing treatment. The process comprises the following main steps of: 1, charging, dissolving, making residues fall, and doping or pre-doping; 2, volatilizing; 3, seeding, shouldering, turning a shoulder, ensuring equal diameter and closing; and 4, closing, catching, lifting the crystal and cooling. Compared with the process in the conventional industry, the process can reduce the thermal donor concentration by 60 to 75 percent, effectively reduces the silicon wafers needing the annealing treatment, reduces cost and improves quality.

Description

technical field [0001] The invention relates to a process for controlling heat donors by solar-grade CZ single crystal silicon rods. Background technique [0002] At present, when producing solar-grade CZ silicon single crystal silicon rods, when the silicon rods are between 350-500 degrees Celsius, a large amount of thermal donors of oxygen will be produced, and the thermal donors are in a double donor state. [0003] At present, in the production of solar-grade CZ silicon single crystal, the existing processes are: [0004] 1. Loading and chemical material (the power of chemical material is generally 1.8-1.9 times the power of equal diameter for 3 hours); [0005] 2. After compounding, doping, hanging shoulders, seeding, laying shoulders, turning shoulders, equal diameter, finishing, and the pulling speed of shoulder turning is 2-4mm / min; [0006] 3. After finishing, the casting speed is 2mm / min, and after cooling for 5 hours, disassemble the furnace and take out the rod...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B15/00C30B15/14C30B29/06
Inventor 石坚
Owner 王正园
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