Polycrystalline silicon ingot, preparation method of polycrystalline silicon ingot and polycrystalline silicon slice

Abstract

The invention discloses a preparation method of a polycrystalline silicon ingot. The preparation method comprises the steps that after a layer of silicon nitride is coated on the inner wall of a crucible, a layer of porous materials are paved on the bottom of the crucible, and then, silicon materials are filled on the porous materials; the crucible filled with silicon materials is heated, the silicon materials are molten to form silicon melts, then, a heat field is regulated, and the silicon melts start to form core crystallization; and when silicon melt interfaces move in a direction away from the bottom of the crucible, and the directional crystallization solidification is completed, the polycrystalline silicon ingot is obtained through annealing cooling. When the preparation method is adopted, the polycrystalline silicon ingot can obtain good initial nucleation, and the dislocation propagation of the polycrystalline silicon ingot in the growth process is reduced. The invention also simultaneously discloses the polycrystalline silicon ingot obtained by the preparation method, and a polycrystalline silicon slice prepared by using the polycrystalline silicon ingot as raw materials.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a polycrystalline silicon ingot, a preparation method thereof and a polycrystalline silicon wafer. Background technique [0002] In recent years, solar energy, as an emerging renewable green energy, has become a hotspot of development and research. With the rapid development of the solar cell industry, polysilicon, which is low in cost and suitable for large-scale production, has become one of the most important photovoltaic materials in the industry, and has gradually replaced the traditional Czochralski monocrystalline silicon in the solar cell material market. [0003] At present, the preparation method of polycrystalline silicon ingot mainly adopts the directional solidification system method (DSS for short) furnace crystal growth technology provided by GT Solar, and this method usually includes steps such as heating, melting, solidification growth, annealing and co...

AI Technical Summary

Problems solved by technology

However, since the initial nucleation is not controlled, dislocations are easily generated during the nucleation process, resulting in disordered crystal orientation and uneven grains, so the quality of polycrystalline silicon ingots prepared by this method is low

The photoelectric conversion efficiency of solar cells made from this polycrystalline silicon ingot is low

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