Crystalline silicon and preparation method thereof

Abstract

The invention relates to a preparation method of crystalline silicon. The preparation method comprises the following steps: laying a filling material at the center of the bottom of a crucible, laying monocrystalline silicon seeds on the filling material to form a monocrystalline silicon seed layer, and laying polycrystalline silicon blocks at the periphery of the filling material and the monocrystalline silicon seed layer to form a polycrystalline silicon seed layer; arranging a silicon material in a molten state on the monocrystalline silicon seed layer and the polycrystalline silicon seed layer, controlling the temperature in the crucible and entering into a crystal growth stage when 10%-90% of the monocrystalline silicon seed layer is molten; and controlling the temperature during crystal growth, forming a temperature gradient which is gradually increased from bottom to top in the direction which is vertical to the bottom of the crucible, and solidifying molten silicon liquid in the fixed direction along the crystal direction of the monocrystalline silicon seed to get the crystalline silicon with monocrystalline silicon at the middle part and polycrystalline silicon at the edge. By adopting the method, the using quantity of the monocrystalline silicon seed is reduced, and the conversion efficiency of an edge silicon chip is improved. The invention further provides the crystalline silicon prepared through the method.

Description

technical field [0001] The invention relates to the field of solar photovoltaic material preparation, in particular to crystalline silicon and a preparation method thereof. Background technique [0002] Solar photovoltaic power generation is one of the fastest-growing forms of sustainable energy utilization, and it has developed rapidly in various countries in recent years. At present, the method of producing monocrystalline silicon for solar energy by casting method has received more and more attention. Cast single crystal silicon has the advantages of low defects of Czochralski single crystal silicon, and can form a pyramid-shaped texture by alkali texturing method, which can improve the absorption of light, thereby improving the conversion efficiency; at the same time, cast single crystal silicon also has the advantages of casting Polysilicon has the advantages of low production cost and high output. Therefore, cast monocrystalline silicon inherits the advantages of Czo...

AI Technical Summary

Problems solved by technology

However, affected by the nucleation of the crucible wall and the solid-liquid interface during crystal growth, polycrystalline nucleation occurs in the silicon ingot near the crucible surface, and a large number of dislocations accumulate, resulting in a silicon wafer in which polycrystalline and single crystal interact. , the conversion efficiency of these edge silicon wafers is low, even lower than that of ordinary polycrystalline silicon wafers

At the same time, due to the high production cost of monocrystalline silicon seed crystals in monocrystalline silicon, the cost of cast monocrystalline silicon wafers is higher than that of ordinary polycrystalline silicon wafers, which seriously restricts the mass production of cast monocrystalline silicon wafers

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