Polysilicon ingot casting device

Abstract

The invention discloses a polysilicon ingot casting device and ingot casting method. The ingot casting device disclosed by the invention comprises a crucible containing a silicon material. The ingot casting device is characterized by also comprising a gas delivery pipe and a power unit, wherein the gas delivery pipe is used for delivering argon gas to silicon liquid obtained by melting the silicon material; the power unit is used for driving the gas outlet end of the gas delivery pipe to charge and discharge the silicon liquid; the gas inlet end of the gas delivery pipe is arranged outside the crucible; and the power output end of the power unit is fixedly connected with the gas outlet end of the gas delivery pipe. The argon gas introduced into the silicon liquid can accelerate the separation of impurities in the silicon liquid from the silicon liquid, so that the impurities contained in the silicon material are quickly separated from the silicon liquid in the molecular motion process and reach to the silicon liquid surface to be volatilized so as to carry the impurities in the silicon liquid away, thereby increasing the impurity volatilization amount, reducing the impurity content in the silicon ingot, and enhancing the quality of the silicon ingot. Meanwhile, the delivery of the argon gas into the silicon liquid is carried out after melting the silicon material into the silicon liquid, and is finished before the silicon liquid crystal growth process; and the process can not prolong the existing ingot casting time or influence the existing ingot casting procedure, and thus, is convenient to implement.

Description

technical field [0001] The invention relates to the technical field of photovoltaic cell production, in particular to a polysilicon ingot casting device. Background technique [0002] Silicon wafers cut from silicon ingots are the most fundamental material for making photovoltaic cells. The quality of silicon ingots directly affects the conversion efficiency of photovoltaic cells, and the most important factor affecting the quality of silicon ingots is the amount of impurities. [0003] The current ingot casting process firstly goes through the spraying-charging process, and then enters the ingot casting process. [0004] Spraying: After the silicon material is melted at high temperature, it will react with the crucible, introduce impurities, and cause the pot to stick to the quality of the silicon ingot. Therefore, it is necessary to spray a layer of silicon nitride solution between the crucible and the silicon material. Using silicon nitride can effectively Separate the s...

AI Technical Summary

Problems solved by technology

However, too long time after the silicon material is melted will lead to the destruction of the silicon nitride coating inside the crucible. Therefore, after the silicon material is melted, it will start to cool down to the crystal growth temperature. The free volatilization time is short, and most of the volatile impurities Before volatilization, it enters the crystal growth stage and solidifies impurities in the silicon ingot, seriously affecting the quality and performance of the silicon ingot itself

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