Silicon crystal keel block having nucleation promoting particles and method for manufacturing the same

Abstract

The invention relates to a silicon crystal keel block and a method for manufacturing the same. The method uses a plurality of nucleation promoting particles to allow a plurality of silicon crystal particles in a silicon melt soup to nucleate on the plurality of nucleation promoting particles and to grow in a vertical direction until the silicon melt soup is fully cured. Each nucleation promoting particle is composed of a main particle and a plurality of subparticles jointed on the surface of the main particle. The average particle size of the plurality of subparticles is smaller than the average particle size of the plurality of main particles.

Description

technical field [0001] The present invention relates to a silicon crystal ingot (crystalline silicon ingot) and its manufacturing method, in particular, to a method of using nucleation promotion particles to make the bottom of the ingot small-sized silicon crystal grains and the overall defect density Low silicon crystal ingots and methods of making the same. Background technique [0002] Most solar cells absorb sunlight to generate a photovoltaic effect (photovoltaic effect). At present, most of the solar cell materials are mainly silicon, mainly because silicon is the second most easily available element on the earth, and it has the advantages of low material cost, no toxicity, high stability, and Its application in semiconductors has a solid foundation. [0003] Silicon-based solar cells are divided into three categories: monocrystalline silicon, polycrystalline silicon, and amorphous silicon. The use of polysilicon as the raw material of solar cells is mainly based on...

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Problems solved by technology

[0008] However, the localized subcooling techniques described above have only been successfully demonstrated in the laboratory

When extended to industrial-grade size, it becomes more difficult for polysilicon casting to control the growth of dendrites on the crystal face and fill the bottom of the crucible with local supercooling

Industrial-grade polysilicon casting is affected by the crucible and the overall heating uniformity. The difference in the control of increasing the initial supercooling degree makes it easy for polysilicon to grow into large grains at the bottom of the crucible and become a region with a high defect density, which grows faster when extending Increase the defect density, resulting in the deterioration of the overall crystal quality of the silicon crystal ingot, and the photoelectric conversion efficiency of the subsequent solar cells is also low

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