Method for manufacturing silicon crystal plate for solar battery

A technology of solar cells and silicon wafers, applied in chemical instruments and methods, circuits, crystal growth, etc., can solve the problems of low material utilization rate, inversion, silicon wafers that cannot be used to prepare solar cells, etc., to improve the utilization rate , high material utilization, and the effect of reducing material cost

Inactive Publication Date: 2008-07-16
CSI CELLS CO LTD
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Problems solved by technology

The cost price of refined metallurgical silicon is low, but the content of phosphorus and boron impurities is relatively high. When using this material to prepare silicon wafers that can be used in solar cells, because boron is an acceptor impurity, when the content of boron is high, silicon The material is P-type, and phosphorus is a donor impurity. When the phosphorus content is high, the silicon material is N-type, because the segregation coefficient of boron in silicon is 0.8, and the segregation coefficient of phosphorus in silicon is It is 0.33, boron is more evenly distributed in the silicon rod after crystal growth, and the content of phosphorus is higher at the rear end. Therefore, in the middle and later stages, the increase of phosphorus content will lead to the inversion of the silicon crystal rod (ingot) material. Some materials cannot be used to make silicon wafers for solar cells
resulting in lower utilization of materials

Method used

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  • Method for manufacturing silicon crystal plate for solar battery
  • Method for manufacturing silicon crystal plate for solar battery

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Embodiment 1

[0017] Embodiment 1: Referring to accompanying drawing 1, a kind of preparation method of the silicon wafer that is used for solar cell, after refined metallurgical silicon is crushed to appropriate size (if the interlayer of incoming material contains more impurity, the diameter of the broken silicon block No more than 4cm), after preliminary selection to remove impurities, put it into an ultrasonic cleaner for cleaning, take it out and put it into a mixed acid solution of nitric acid and hydrofluoric acid for cleaning to remove surface impurities, and then put it into a high-purity quartz crucible , add gallium with an atomic concentration of 12.0ppma, put the quartz crucible into the graphite crucible in the single crystal furnace, then evacuate the single crystal furnace, and then fill it with argon as a protective gas, heat the furnace body, and the heating temperature exceeds The melting point of the silicon material melts the raw material in the crucible and keeps it war...

Embodiment 2

[0024] Example 2: A method for preparing silicon wafers for solar cells. After crushing refined metallurgical silicon to an appropriate size, after preliminary selection to remove impurities, put it into an ultrasonic cleaner for cleaning, and then put nitric acid and hydrogen into it after taking it out. Fluoric acid mixed acid solution to remove surface impurities; then put into a high-purity quartz crucible, and add gallium with an atomic concentration of 12.2ppma, place the quartz crucible on a heat exchange table (polycrystalline growth furnace), and Vacuumize to reduce the pressure to 0.05-0.1mbar, feed argon as a protective gas, and maintain the pressure in the furnace at about 400-600mbar; slowly heat to about 1200-1300°C, and the process takes 4 to 5 hours; gradually increase the heating power , so that the temperature in the quartz crucible reaches about 1500 ° C, the silicon raw material begins to melt, and the heat preservation is completed until the chemical materi...

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Abstract

The invention discloses a preparing method of a silicon wafer used in a solar cell. At first refining metallurgical silicon is crushed, and visible impurity is removed, and then the silicon is chemically cleaned and thrown into a crystal bar (or ingot) growth furnace, and at the same time, gallium or gallium phosphide is added into the furnace, and the amount is 5 to 14ppma calculated according to the atomic concentration of gallium. After the crystal rod (or ingot) finishes growing, ingot sections processing measurement is operated, and then the needed silicon wafer can be obtained. The method of the invention can use refining metallurgical silicon for producing solar cells, and the method reduces the material cost and is beneficial to the popular application of silicon solar cells.

Description

technical field [0001] The invention relates to a method for manufacturing a silicon substrate for a solar cell, in particular to a method for preparing a low-cost silicon wafer for a solar cell by using refined metallurgical silicon. Background technique [0002] With the development of modern industry, the demand for energy is increasing, but the use of conventional energy will release a large amount of carbon dioxide gas, resulting in a global "greenhouse effect", so countries are trying to get rid of the dependence on conventional energy, Accelerate the development of renewable energy. As one of the most ideal renewable energy sources, the utilization of solar energy has been highly valued. Although research on solar cells has been carried out for three to forty years, solar cells have only been widely used in recent years. The rapid development of the solar industry has greatly reduced its manufacturing cost, but at the same time it has also led to a rapid rise in the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/06C30B15/04
CPCC30B28/06H01L31/182C30B11/00C30B29/06Y02E10/546Y02P70/50
Inventor 陈根茂彭江
Owner CSI CELLS CO LTD
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