Method for assisting polycrystalline silicon ingot casting by electrostatic field

Abstract

The invention discloses a method for assisting polycrystalline silicon ingot casting by an electrostatic field. The method includes the steps: (1) placing two electrode plates on the upper side and the lower side of a polycrystalline ingot casting crucible and keeping the two electrode plates parallel; (2) externally connecting the electrode plates with a high-voltage power supply and outputting stable voltage to the electrode plates; (3) keeping electric field intensity stabilized at a certain concrete value within the range of 1V / cm-100000V / cm, and performing a polycrystalline silicon ingot casting process; (4) finishing ingot casting and powering off the electrode plates to obtain a polycrystalline silicon cast ingot with an excellent performance. Polycrystalline silicon grains can be enlarged, orientation is enhanced, various charged impurities in polycrystalline silicon can be efficiently removed, polycrystalline silicon quality is substantially improved, operation is simple, stability is good, and batch production can be performed. A figure 1 is an electric field application diagram in embodiments 1 and 2 and includes a lead 1, a graphite electrode 2, the ingot casting crucible 3 and the high-voltage power supply 4.

Description

Technical field [0001] The invention belongs to the field of crystalline silicon production, and relates to a method for producing polysilicon, in particular to a method for producing polysilicon assisted by an electrostatic field. Background technique [0002] In recent years, the new energy industry led by solar energy has developed extremely rapidly. The main raw material in the field of solar cells is silicon, which accounts for 90% of the total raw materials. Among silicon materials, polycrystalline silicon materials account for the majority, so the quality of polycrystalline silicon wafers It directly affects the improvement of product quality and cost reduction in the solar cell industry. [0003] At present, the key problems in the production of polysilicon are the poor crystal quality, the difficulty of controlling the crystal flower size and orientation, and the difficulty of removing impurity ions in the crystal. These impurity ions seriously affect the performance param...

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Problems solved by technology

[0003] At present, the key problems in the production of polysilicon are poor crystal quality, difficult to control the size and orientation of crystal flowers, and difficult to remove impurity ions in the crystal. These impurity ions seriously affect the performance parameters of polysilicon, hindering the improvement of solar cell efficiency and cost reduction

In the production of polysilicon, quasi-single crystal technology, semi-melting stepping technology, directional solidification technology, etc. are mostly used in order to improve the quality of silicon wafers and remove impurity ions, but no good results have been obtained.

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