Seed crystal jointing structure for oriented solidification of cast ingots

Abstract

The invention relates to a seed crystal jointing structure for oriented solidification of cast ingots. The seed crystal jointing structure comprises jointed seed crystal blocks, wherein jointing surface betweens two seed crystal blocks are planes which are vertical to the bottom of a crucible; a transverse columnar hole vertical to the jointing planes is formed in each seed crystal block; after adjacent seed crystal blocks are jointed, the transverse columnar holes are jointed to form a bar-shaped columnar cavity; a silicon rod inserts the columnar cavity. The transverse columnar holes are formed in the seed crystal blocks; two ends of the silicon rod insert the columnar holes of adjacent seed crystal blocks, thus jointing of the seed crystal blocks is realized; the jointing manner has a mortise-and-tenon jointing structure, thus lamination of the seed crystal jointing surfaces is improved. During heating, seed crystal at the edges is expanded by heating and the mortise-and-tenon jointing structure becomes relatively tight, thus expanding of seams caused by wrapped edges of the seed crystal blocks is prevented. The silicon rod and the columnar holes can be processed at one time through a drilling machine and are easily realized in industries; the jointing (inserting) method is simple, is easy to be mastered by operators and has relatively high practical value.

Description

technical field [0001] The invention relates to a splicing structure of seed crystals for directional solidification ingots, 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 common manufacturing method of silicon-like single crystal is the directional solidification method. In this method, cuboid seed crystals are laid on the bottom of the flat-bottomed crucible, and the seed crystals are arranged regularly to form a seed crystal layer. The silicon material is placed in a flat-bottomed crucible and laid on the seed crystal 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 re...

AI Technical Summary

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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