Polycrystalline silicon ingot and manufacturing method thereof as well as solar cell

Abstract

The embodiment of the invention discloses a polycrystalline silicon ingot and a manufacturing method thereof as well as a solar cell. The manufacturing method comprises the following steps: placing or spraying a high-purity material at the bottom of a container in a polycrystalline growth furnace to form an isolation protecting layer; paving seed crystals on the isolation protecting layer to form a seed crystal layer; loading a solid silicon raw material on the seed crystal layer; heating the container, melting the silicon raw material and a part of seed crystal layer to form a liquid layer, wherein at least the part contacting the isolation protecting layer, of the seed crystal layer is kept to be solid; and controlling the thermal field in the polycrystalline silicon ingot growth furnace, and crystallizing the liquid layer to lead the solid-liquid interface to move along the direction away from the bottom of the container until the polycrystalline silicon grows completely. The polycrystalline silicon ingot cast by the invention comprises most of monocrystalline silicon areas, the impurity content in the polycrystalline ingot is reduced due to the isolation protecting layer, and the solar cell produced by the polycrystalline silicon ingot has improved photoelectric conversion efficiency.

Description

technical field [0001] The invention relates to a polysilicon manufacturing technology, in particular to a polysilicon ingot, a manufacturing method thereof, and a solar cell. Background technique [0002] Energy and the environment are two major issues that are widely concerned in the world today. As a renewable green energy, solar energy has naturally become the focus of people's development and research. With the rapid development of the solar cell industry, polysilicon, which is low in cost and suitable for mass production, has become one of the most important photovoltaic materials and gradually replaced the traditional Czochralski monocrystalline silicon in the solar cell material market. [0003] At present, the method of preparing polycrystalline silicon ingots for solar cells is mainly the directional solidification method, that is, during the solidification process of molten raw silicon, by controlling the temperature gradient of the solid-liquid interface to imple...

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Problems solved by technology

[0005] However, in the actual production process, it is found that the solar cells made of polycrystalline silicon ingots produced by the DSS method often have problems such as low photoelectric conversion efficiency. The inventors have found that the reason for the above problems is that the polycrystalline silicon ingots produced in the prior art The impurity content and defect density are high, which directly affects the photoelectric conversion efficiency of solar cells.

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