Method for bonding and splicing seed crystals for monocrystalline silicon ingots and crucible for ingots

Abstract

The invention provides a bonding and splicing method of seed crystals for monocrystal silicon-like cast ingots. According to the method, an inorganic bonder is adopted for bonding and splicing adjacent seed crystals together to form a seed crystal layer, wherein the inorganic bonder is filled into splicing seams of the seed crystals in the seed crystal layer. When the seed crystal layer is applied to the monocrystal silicon-like cast ingots, defects such as polycrystal and dislocation at seed crystal splicing seams in the ingot casting process can be effectively avoided, the monocrystal silicon-like cast ingots with small defects and high conversion efficiency can be obtained, and the ratio that full-monocrystalline silicon pieces are obtained is greatly improved. The invention further provides a crucible for casting ingots with seed crystal layers. The crucible is applicable to on-scale production of high-quality monocrystal silicon.

Description

technical field [0001] The invention relates to the field of silicon crystal manufacturing, in particular to a method for bonding and splicing seed crystals for quasi-monocrystalline silicon ingots and a crucible for ingots. Background technique [0002] At present, the common manufacturing method of silicon-like single crystal is the directional solidification method. In this method, the seed crystal is laid on the bottom of the flat-bottomed crucible, and the seed crystals are tightly spliced ​​to form a seed crystal layer; then the silicon material is loaded on the seed crystal layer; Through welding control, the molten silicon material is seeded and grown on the seed crystal at the bottom to obtain similar or identical grains to the seed crystal. [0003] Using the above method to grow quasi-single crystals, the main disadvantages include: [0004] Seed crystals are obtained by mechanical cutting, so there will be damaged layers or crystal dangling bonds on the surface....

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Problems solved by technology

[0004] Seed crystals are obtained by mechanical cutting, so there will be damaged layers or crystal dangling bonds on the surface. During the seeding process of quasi-single crystals, the surface defects of seed crystals can easily lead to the generation of dislocations, which will continue to multiply and develop, affecting subsequent crystals. quality;

[0005] The seed crystal layer is made of multiple single-crystal seed crystals by physical splicing, so it is difficult to ensure that there are no gaps between the seed crystals and the seed crystals; during the materialization process, the silicon liquid that is first melted on the upper part of the seed crystals will flow down along the gaps , even into the bottom of the seed crystal; and when the silicon liquid flows down in the gap, the cooling rate is relatively fast, so it is easy to generate dislocation defects and polycrystals in the gap; dislocations or polycrystals in these gaps are in the process of seeding It is easy to seed it up, resulting in polycrystalline regions and dislocation defects in the side and seed crystal gaps in the subsequent stage. Polycrystalline and dislocations affect the texturing effect and conversion efficiency of similar monocrystalline silicon wafers, thereby affecting similar The quality of monocrystalline silicon ingot

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