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Method for increasing crystal pulling stability of large-diameter monocrystalline silicon with diameter of over 400 mm

A silicon crystal pulling and stability technology, applied in the self-melting liquid pulling method, single crystal growth, single crystal growth, etc. , dislocation increase, etc.

Inactive Publication Date: 2014-07-09
NINGXIA UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, as the size of crystalline silicon increases, the structure of the furnace increases accordingly. Compared with the traditional small-diameter single-crystalline silicon production process, the thermal field and gas flow field in the furnace change accordingly, which will greatly affect the crystallization process. The shape of the solid-liquid interface during the growth process of silicon and the mass transfer and heat transfer in the micro-area. In the initial stage of isodiametric growth of crystalline silicon, a typical "W-shaped" solid-liquid interface is formed in large-diameter single crystal silicon. This type of interface intensifies the interface fluctuation during the growth process, thereby reducing the stability of the crystal pulling process, and the probability of occurrence of defects such as crystal outages and dislocations increases during the growth process.

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  • Method for increasing crystal pulling stability of large-diameter monocrystalline silicon with diameter of over 400 mm
  • Method for increasing crystal pulling stability of large-diameter monocrystalline silicon with diameter of over 400 mm
  • Method for increasing crystal pulling stability of large-diameter monocrystalline silicon with diameter of over 400 mm

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Embodiment 1

[0024] The size of the quartz crucible in the production process of producing monocrystalline silicon by the Czochralski method is set to 800mm; in the isometric growth step of producing monocrystalline silicon by the Czochralski method, the range value of the liquid opening distance is controlled at the initial stage of equal diameter to be 15mm , and the furnace pressure is 22 Torr, the rotation speed of the quartz crucible is 5 rpm, the rotation speed of the crystal is 8 rpm, the isodiametric pulling speed is 0.75 / min, and the inlet argon flow rate is 1.2 m / s.

[0025] The analysis of single crystal silicon rods with an equal diameter of 300 mm shows that the distribution curve of the solid-liquid interface is as follows: figure 2 As shown, the height at the center of the solid-liquid interface (point A) and the maximum point of the solid-liquid interface curve (point B) are analyzed, and it can be concluded that compared with the unimproved process, the solid Fluctuation ...

Embodiment 2

[0027] The size of the quartz crucible in the production process of producing monocrystalline silicon by the Czochralski method is set to 900mm; ~20mm, and the furnace pressure is 22Torr, the rotation speed of the quartz crucible is 6rpm, the rotation speed of the crystal is 9rpm, the isometric pulling speed is 1mm / min, and the inlet argon gas flow rate is 1.2m / s.

[0028] The analysis of single crystal silicon rods with an equal diameter of 300 mm shows that the distribution curve of the solid-liquid interface is as follows: Figure 5 As shown, the height at the center of the solid-liquid interface (point A) and the maximum point of the solid-liquid interface curve (point B) are analyzed, and it can be concluded that compared with the unimproved process, the solid Fluctuation intensity of liquid interface decreased from 7.39% to 5.5%; for further details, please refer to Figure 6 and Figure 7 , Figure 6 It is the cloud diagram of the stress distribution of the monocryst...

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Abstract

The invention discloses a method for increasing the crystal pulling stability of large-diameter monocrystalline silicon with a diameter of over 400 mm. The method is applied to a production process of manufacturing monocrystalline silicon by using a direct pulling method. The method for increasing the crystal pulling stability of large-diameter monocrystalline silicon with a diameter of over 400 mm comprises the following steps that: the size of a quartz crucible used in the production process of manufacturing monocrystalline silicon by using the direct pulling method is set at 800 mm or more; in an isodiametric growth step of manufacturing monocrystalline silicon by using the direct pulling method, the range value of the liquid filling hole distance is controlled at 15-20 mm at the isodiametric initial stage.

Description

technical field [0001] The invention relates to the technical field of monocrystalline silicon manufacturing for solar power generation, in particular to a method for improving the stability of single crystal silicon with a diameter of more than 400 mm. Background technique [0002] Crystalline silicon solar cells account for more than 90% of the entire photovoltaic market. The Czochralski method is one of the main production methods for preparing crystalline silicon products. Among them, the process of preparing monocrystalline silicon by the Czochralski method is mainly divided into several stages: chemical material, seeding, shouldering, equal diameter, finishing and cooling. [0003] So far, the conversion efficiency of monocrystalline silicon cells prepared by the Czochralski method has reached more than 23%, but the cost of power generation is still high, which greatly limits the popularization of this product. Larger diameter is one of the inevitable trends in the de...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/06C30B27/02C30B15/20
Inventor 李进高忙忙薛子文李海波李国龙梁森张洪岩何力军
Owner NINGXIA UNIVERSITY