Seed crystal splicing method used for monocrystal-like silicone cast ingot

Abstract

The invention discloses a seed crystal splicing method used for monocrystal-like silicone cast ingot, and used for directional solidification method monocrystal-like silicone cast ingot. Seed crystal layers are formed by seed crystal closely arrayed. An alpha angle is formed between the tangential direction of at least one of spliced surfaces of every two blocks of seed crystal and the normal direction of a plane at the bottom of a crucible, wherein 0 degree < alpha <90 degrees. The seed crystal splicing method that the splicing surface is tangent to the normal direction of the plane at the bottom of the crucible, and the splicing surface does not coincides with the normal direction of the plane at the bottom of the crucible is adopted. The shape of the seed crystal is changed to reduce dislocation source and even the generation of polycrystalline grain boundaries, all-momocrystal is achieved, and monocrystal-like with less dislocation source grows. Therefore, dislocation defect of silicon slices is reduced, monocrystal area proportion is increased, photoelectric conversion efficiency of a solar battery is improved, the service life of the battery is prolonged, and therefore the performance of a photovoltaic device is improved.

Description

technical field [0001] The invention relates to the field of silicon crystal manufacturing, in particular to a method for splicing seed crystals for quasi-monocrystalline silicon ingots. 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 contained 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...

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Problems solved by technology

[0007] In summary, under the splicing method of regular arrangement of cuboid seed crystals, dislocation sources are easy to be generated during the growth of quasi-single crystals by directional solidification method, which in turn leads to the proliferation of dislocations in subsequent crystals, or the formation of polycrystalline grain boundaries.

[0008] Studies have shown that grain boundaries lead to a decrease in the proportion of single crystal area, dislocations lead to the formation of a large number of defects in silicon wafers, the photoelectric conversion efficiency of solar cells is reduced, and the service life is shortened, thereby affecting the performance of photovoltaic devices

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