Polycrystalline silicon ingot, manufacturing method thereof and solar cell

Abstract

The invention discloses a manufacturing method of a polycrystalline silicon ingot. The manufacturing method comprises the steps of paving seed crystals on the bottom of a container in a polycrystalline silicon ingot growth furnace to form a seed crystal layer; loading solid silicon raw materials on the seed crystal layer; heating the container to melt the silicon raw materials and part of seed crystal layer to form a liquid layer, and at least keeping part of the seed crystal layer contacted with the bottom of the container to be in the solid state; controlling a thermal field in the polycrystalline silicon ingot growth furnace, and crystallizing the liquid layer to form a crystallization layer so as to move a solid-liquid interface to the direction far away from the bottom of the container; moving the solid-liquid interface to the direction far away from the bottom of the container by a corresponding distance, then conducting the meltback crystallization process, at least implementing the meltback crystallization process once to obtain the polycrystalline silicon ingot. The polycrystalline silicon ingot produced by adopting the method disclosed by the invention is low in impurity content, the produced solar cell is low in cost and attenuation coefficient, and the photoelectric conversion efficiency is high.

Description

technical field [0001] The invention relates to the manufacturing technology of monocrystalline silicon and polycrystalline silicon and the field of optoelectronics, in particular to a polycrystalline silicon ingot, a manufacturing method thereof, and a solar battery. Background technique [0002] Solar cells can convert light energy into electrical energy. The photoelectric conversion efficiency and the speed of battery attenuation are important parameters to measure the quality of solar cells. At present, according to different materials, solar cells are mainly divided into two types: monocrystalline silicon solar cells and polycrystalline silicon solar cells. [0003] Among them, the monocrystalline silicon ingot is formed by melting the silicon raw material containing dopant, and then pulling the crystalline silicon out of the melting region to crystallize. Usually, the method of producing single crystal silicon ingot is the melt Czochralski method (Czochralski method, r...

AI Technical Summary

Problems solved by technology

Compared with monocrystalline silicon ingots, there are more defects in polycrystalline silicon ingots, the grains are small, and there are more grain boundaries and dislocations between conventional polycrystalline silicon grains, resulting in rapid recombination of charge carriers, resulting in low minority carrier lifetime. , and, because the orientation between crystal grains is random, it is difficult to texture the surface of the wafer well, so that the photoelectric conversion efficiency of conventional polycrystalline silicon solar cells is lower than that of monocrystalline silicon solar cells, but the oxygen content in polycrystalline silicon ingots It can be controlled at a good level, so that the attenuation coefficient of polycrystalline silicon solar cells is low

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