Method and device for improving uniformity of axial resistivity of czochralski monocrystalline silicon

Abstract

The invention discloses a method and a device for improving the uniformity of the axial resistivity of czochralski monocrystalline silicon. The device comprises a doping agent container, a mass flowmeter, an electromagnetic valve and a conveying pipe. The method comprises the following steps of (1), preparation before the start of the pulling of monocrystalline silicon; (2), melting of a polycrystalline-silicon raw material; (3), seeding; (4), shouldering; (5), shoulder rotation; (6), diameter equaling; (7), ending. The method and the device for improving the uniformity of the axial resistivity of the czochralski monocrystalline silicon have the advantages that (1), a conventional doping way in a czochralski process is changed, the uniformity of an axial doping element in the monocrystalline silicon is improved, and further, the uniformity of the axial resistivity is improved; (2), the device provided by the invention is simple in structure and is convenient to operate.

Description

[0001] Technical field: [0002] The invention relates to the field of semiconductor materials, in particular to a method and a device for improving the axial resistivity uniformity of Czochralski single crystal silicon. [0003] Background technique: [0004] Monocrystalline silicon is an important material for solar power generation. With the development of crystalline silicon cell technology, the uniformity of axial resistivity of single crystal silicon is required to be increased (the axial resistivity range is required to be narrowed). The resistivity in single crystal silicon is related to the amount of doping elements entering the single crystal silicon, the more the amount of doping elements, the lower the resistivity. [0005] The conventional doping method in the Czochralski process is: directly put the doping elements into the crucible when charging the material, melt together with the silicon material, and melt into the silicon melt. The solubility in phase silicon...

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Problems solved by technology

[0005] The conventional doping method in the Czochralski process is: directly put the doping elements into the crucible when charging the material, melt together with the silicon material, and melt into the silicon melt. The solubility in phase silicon is less than that in liquid phase silicon, that is, the segregation coefficient in silicon is less than 1. During the crystal pulling process, some doping elements will enter the silicon single crystal, and some doping elements will be discharged into the molten silicon. In the bulk silicon, the concentration in the molten silicon gradually increases, and then the resistivity gradually decreases. There are differences in the concentration of doping elements at the head and tail of the entire single crystal silicon rod, and the drawn single crystal silicon cannot meet the axial requirements. Requirements for uniform resistivity

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