Method for reducing content of carbon in single crystal bar

Abstract

The invention discloses a method for reducing content of carbon in a single crystal bar. The method specifically comprises steps as follows: (1) a thermal field below a liquid level is mounted at thelower end of a furnace tube; (2) a material block is put in a crucible by means of a hoisting procedure, material protecting cloth is uniformly spread, wherein traction wires are uniformly arranged onone surface of the material protecting cloth, all the traction wires are connected together through a traction wire guide block, the traction wire guide block is arranged in the center of the material protecting cloth, the surface without traction wires completely covers the material blocks put in the crucible, and the crucible is descended to the lower limit position in the furnace tube and located at the upper end of the thermal field below the liquid level; (3) a thermal field above the liquid level is mounted, and the furnace tube is started to be closed after mounting; (4) after the furnace tube is closed, the traction wire guide block is lifted upwards, the material protecting cloth is directly taken out, and the furnace is continuously closed; (5) after the tube is closed, the material protecting cloth is turned over in the designated position of a workshop, so that lifted graphite powder and other impurities are lifted, then, the material protecting cloth is blown clean on thewhole with a blower, and the material protecting cloth and a sucker are transported to a charging chamber.

Description

technical field [0001] The invention relates to a method for reducing the carbon content in a single crystal rod. Background technique [0002] The existing carbon content control methods in the single crystal industry mainly include the following two types: (1) Strictly control the service life of graphite parts, and replace graphite parts once slag or slight cracks appear, which greatly reduces carbon content. The service life of graphite parts is shortened, and graphite parts must be calcined for each major graphite part replacement, which increases the invalid working hours of the furnace, which increases the overall price of monocrystalline silicon wafers; (2) in a The first method is to increase the last pot bottom material to control the carbon content at the tail of the crystal rod. This method can greatly reduce the carbon content at the tail of the crystal rod, but the waste of silicon material is serious. Contents of the invention [0003] The technical problem...

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Problems solved by technology

[0002] The existing carbon content control methods in the single crystal industry mainly include the following two types: (1) Strictly control the service life of graphite parts, and replace graphite parts once slag or slight cracks appear, which greatly reduces carbon content. The service life of graphite parts is shortened, and graphite parts must be calcined for each major graphite part replacement, which increases the invalid working hours of the furnace, which increases the overall price of monocrystalline silicon wafers; (2) in a The first method is to increase the last pot bottom material to control the carbon content at the end of the ingot. This method can greatly reduce the carbon content at the end of the ingot, but the waste of silicon material is serious

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