Seed crystal growth process method

Abstract

The invention discloses a seed crystal growth process method, which comprises the following steps: placing a silicon material in a furnace body, and heating; heating the furnace body to a first preset stage, wherein the pressure in the furnace body is set to be 90-100 mbar, and the air inlet amount and the air outlet amount in the furnace body are both smaller than 10 nl / min; and heating the furnace body to a second preset stage, wherein the pressure in the furnace body is set to be 250-350 mbar, and the air inlet amount and the air outlet amount in the furnace body are both smaller than 10 nl / min. According to the seed crystal growth process method, the pressure in the furnace body is controlled, and the air inlet amount and the air outlet amount are both smaller than 10 nl / min, so that the airflow flowing speed can be reduced, the airflow can be prevented from flowing to the bottom of the furnace body, impurities at the bottom in the furnace body can be prevented from being excited by the airflow, the impurities can be prevented from being fused with a silicon material, and the seed crystal purity is improved.

Description

technical field [0001] The invention relates to the technical field of quasi-single crystal technology, in particular to a seed crystal growth process method. Background technique [0002] The growth of a quasi-single crystal requires a completely symmetrical thermal field structure. An obvious feature of a symmetrical thermal field structure is that the melt fluidity will be weaker. During the casting process, when the gas flows to the bottom of the crucible, the The inside of the coating contains more impurities, and the gas itself will also carry impurities. The gas arouses the "floating dust" of coating impurities. As the gas flows upward, it reacts with silicon vapor at high temperature to form silicon nitride, silicon carbide, Silicon oxide and other composite oxides, etc., are deposited in the gap of the seed crystal or on the silicon material, and different colored films will appear. [0003] The impurities deposited in the gap between the seed crystals flow upward ...

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Problems solved by technology

[0003] The impurities deposited in the gap between the seed crystals flow upward with the gas into the upper silicon material, but the symmetric thermal field structure of the single crystal, the melt fluidity is weak, and it is difficult for the impurities to be discharged to the silicon ingot through segregation head, while remaining in the silicon ingot, thereby detecting black impurity spots

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