Reutilization method of seed crystals for casting monocrystals

Abstract

The invention provides a reutilization method of seed crystals for casting monocrystals, which comprises the following steps: (1) providing a crucible, and splicing and laying monocrystal silicon seed crystals on the bottom of the crucible to obtain a seed crystal layer; arranging a molten silicon material on the seed crystal layer, and controlling the temperature so that the molten silicon material grows on the monocrystal silicon seed crystal by continuing the crystal orientation structure of the monocrystal silicon seed crystal, thereby obtaining a monocrystal-like silicon bulk; (2) taking out the monocrystal-like silicon bulk, and cutting the seed crystal position on the bottom of the monocrystal-like silicon bulk to obtain a whole seed crystal, wherein the size and shape of the top of the seed crystal are basically the same as those of the bottom of the monocrystal-like silicon bulk; and (3) laying the seed crystal obtained in the step (2) on the bottom of the crucible, and preparing the monocrystal-like silicon bulk according to the step (1). The method provided by the invention can not cause the phenomena of edge breakage and broken corner in the seed crystals, and can not introduce new splice seams into the seed crystals. The prepared monocrystal-like silicon bulk has the advantages of less dislocation and good quality, and greatly lowers the seed crystal cost for casting monocrystals.

Description

technical field [0001] The invention relates to the field of quasi-single crystal silicon ingots, in particular to a method for reusing seed crystals for casting quasi-single crystals. Background technique [0002] At present, casting single crystal mainly adopts the method of laying single crystal silicon seed crystal on the bottom of the crucible. Taking G5 silicon ingot as an example, according to figure 1 As shown, the monocrystalline silicon seed crystals with a length × width × height of 156 mm × 156 mm × 30 mm were spliced ​​in a 5 × 5 manner in a crucible with an inner diameter of length × width 840 mm × 840 mm to obtain a seed crystal layer, and then The silicon material in molten state is set above the crystal layer, and the temperature at the bottom of the crucible is controlled to be lower than the melting point of the seed crystal, so that the seed crystal is not completely melted; the temperature drops to enter the growth stage, and the silicon material grows o...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the above problems, the present invention provides a method for reusing seed crystals for casting single crystals. The method of the present invention is simple in process, and the seed crystals are not prone to edge chipping and chipping, and the seed crystals do not increase during the recycling process. The new splicing seam can obtain less single-crystal dislocations, which solves the problems of edge chipping and large dislocations that are easy to occur in the process of reusing the seed crystals in the prior art

Images