Seed crystal splicing structure for like single crystal silicon cast ingot

Abstract

The invention relates to a seed crystal splicing structure for a like single crystal silicon cast ingot. The seed crystal splicing structure comprises mutually spliced seed crystal blocks, a splicing surface between adjacent seed crystal blocks is a plane, an included angle alpha is formed between the plane and the bottom of a crucible and ranges from 30 degrees to 60 degrees, a rectangular slot is formed in the seed crystal block on one side of each splicing surface, and a rectangular bump suitable for inserting into the slot is arranged on the seed crystal block on the other side of the splicing surface. After the adjacent seed crystal blocks are spliced, the bumps are inserted into the slots, and the gaps between the splicing surfaces are smaller than 0.5mm. The splicing surfaces of the seed crystal blocks are provided with bumps and the slots which are mutually matched to form mortise and tenon joint structures, and the fitting degree of the splicing surfaces of the seed crystal blocks is improved. In the heating process, seed crystals at the edge are heated to expand, so that the mortise and tenon joint structures are closer, welding seams are changed smaller, the adjacent seed crystal blocks are closely fitted, largeness of the gaps caused by projecting of the edges of the seed crystal blocks are prevented, so that dislocation of the crystals is furthest decreased, and single crystal area ratio is increased.

Description

technical field [0001] The invention relates to a seed crystal splicing structure for a monocrystalline silicon ingot, and belongs to the field of silicon crystal manufacturing. Background technique [0002] In recent years, silicon single crystal and silicon polycrystalline have been widely used in photovoltaic solar cells, liquid crystal display and other fields. At present, the commonly used manufacturing method of silicon-like single crystal is the directional solidification method. In this method, cuboid seed crystals are laid on the bottom of a flat-bottomed crucible, and the seed crystals are regularly arranged to form a seed crystal layer. The silicon material is placed in a flat-bottomed crucible and laid on the seed layer. Through the temperature control in the melting stage, after the silicon material is melted, the seed crystal gradually melts from the surface in contact with the silicon liquid, and then the directional growth of the silicon ingot is realized on...

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Problems solved by technology

[0005] However, the inventor has found through experiments that the above-mentioned method still has defects.

Although the bevel splicing reduces the generation of gaps to a certain extent, due to the smooth bevel, the seed crystal splicing method may cause deformation of the seed crystal splicing due to pressure during the seed crystal splicing and silicon filling process, thus affecting the quality of the subsequent single crystal ingot. , the splicing of the seed crystal puts forward very high technical requirements, and the process tolerance performance becomes worse

At the same time, during the heating process, the tightly arranged seed crystals may warp due to thermal expansion, and the splicing gap between the seed crystals will become larger, resulting in the proliferation of subsequent crystal dislocations, or the formation of polycrystalline grain boundaries

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