Preparation method of efficient polycrystalline silicon ingot and efficient polycrystalline silicon ingot

Abstract

The invention is suitable for the technical field of photovoltaic cells, and provides a preparation method of efficient polycrystalline silicon ingot and efficient polycrystalline silicon ingot. The method includes the following steps of: coating a protective layer on the inner surface of a crucible, wherein the materials of the protective layer includes silicon nitride and pure water; coating a seeding layer on the upper surface of the protective layer coated on the bottom surface of the crucible, wherein the materials of the seeding layer comprises silicon nitride, pure water and silicon powder; placing polycrystalline silicon raw material in the crucible coated with the seeding layer, and placing the crucible in an ingot furnace, and vacuumizing the ingot furnace; heating the ingot furnace to a first preset temperature to completely melt the polycrystalline silicon raw material and the silicon powder to form silicon liquid; forming a super-cooling state at the bottom of the crucibleso that the silicon liquid forms crystal a nucleus at the bottom of the crucible; and the silicon liquid except for forming the crystal nucleus crystallize on the basis of the crystal nucleus to growinto efficient polycrystalline silicon ingot. According to the invention, the process difficulty can be reduced, and the material melting time can be saved.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic cells, and in particular relates to a method for preparing a high-efficiency polycrystalline silicon ingot and the high-efficiency polycrystalline silicon ingot. Background technique [0002] High-efficiency polycrystalline silicon ingot has the advantages of low dislocation density, regular grain boundary structure and uniform grain distribution, and is a common material for making photovoltaic cells. At present, the common method of preparing high-efficiency polysilicon ingots is to lay crushed silicon material on the bottom of the crucible, and then put the polysilicon raw material into the crucible. The silicon material is used as the seed crystal, from which the nucleation begins to grow, and finally a high-quality silicon ingot is obtained. However, in this method, since it is necessary to ensure that when the polysilicon raw material is completely melted, the crushed silicon material ...

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Problems solved by technology

[0003] In view of this, the embodiment of the present invention provides a method for preparing a high-efficiency polycrystalline silicon ingot and a high-efficiency polycrystalline silicon ingot to solve the problems in the prior art that it is difficult to control the melting state of the crushed silicon material and the process is difficult when preparing a high-efficiency polycrystalline silicon ingot

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