Cooling process of czochralski single-crystal method

Abstract

The invention provides cooling process of a czochralski single-crystal method. During cooling, cooling gas is stopped being introduced in a furnace body, at the same time, a vacuum pump is closed, and therefore sealed space is formed. Gas in the furnace body serves as a medium and transmits more heat to flowing water of a furnace wall, and therefore cooling efficiency is high. On the condition that quality, the crystal rate and the production period of czochralski single-crystal bars are guaranteed, the cooling process enables czochralski method cooling process to be remarkably efficient, greatly lowers use amount of the cooling gas, and therefore lowers production cost of the czochralski method to a large extent.

Description

technical field

[0001] The invention relates to a cooling process of a Czochralski single crystal method, which belongs to the field of solar photovoltaics. Background technique

[0002] More than 80% of the solar cells produced in the world use crystalline silicon, of which monocrystalline silicon accounts for about 40%. The biggest advantage of monocrystalline silicon is its high conversion efficiency, but the production cost is relatively high. Therefore, how to ensure the quality of silicon wafers Under the premise of the industry, reducing production costs has become the direction of the industry's joint efforts and concerns.

[0003] Under normal circumstances, the cooling process of the Czochralski single crystal method is carried out under the environment of feeding a cooling gas (usually argon). Since the whole system is in an open state, the residence time of the fed argon in the furnace is relatively short, and finally The heat taken away is 80%-85% of the total ...

Examples

Embodiment 1

[0009] A cooling process of the Czochralski single crystal method. After the cooling stage is carried out for 0.8 hours, the temperature in the furnace drops to 1220 ° C and the pressure is 30 Pa. Stop feeding argon into the furnace and turn off the vacuum pump to form a In the pressure-holding state, the pressure is 50 Pa, and it is maintained for 4.2 hours until the whole Czochralski method single crystal preparation process ends.

Embodiment 2

[0011] A cooling process of the Czochralski single crystal method. After the cooling stage is carried out for 1.0h, the temperature in the furnace drops to 1250°C and the pressure is 32Pa. Stop feeding argon into the furnace and turn off the vacuum pump to form a In the pressure-holding state, the pressure is 53 Pa, and it is maintained for 4.5 hours until the whole Czochralski method single crystal preparation process ends.

Embodiment 3

[0013] A cooling process of the Czochralski single crystal method. After the cooling stage is carried out for 1.2 hours, the temperature in the furnace drops to 1280 ° C and the pressure is 34 Pa. Stop feeding argon into the furnace and turn off the vacuum pump to form a In the pressure-holding state, the pressure is 56 Pa, and it is maintained for 4.8 hours until the whole Czochralski method single crystal preparation process ends.

technical field

[0001] The invention relates to a cooling process of a Czochralski single crystal method, which belongs to the field of solar photovoltaics. Background technique

[0002] More than 80% of the solar cells produced in the world use crystalline silicon, of which monocrystalline silicon accounts for about 40%. The biggest advantage of monocrystalline silicon is its high conversion efficiency, but the production cost is relatively high. Therefore, how to ensure the quality of silicon wafers Under the premise of the industry, reducing production costs has become the direction of the industry's joint efforts and concerns.

[0003] Under normal circumstances, the cooling process of the Czochralski single crystal method is carried out under the environment of feeding a cooling gas (usually argon). Since the whole system is in an open state, the residence time of the fed argon in the furnace is relatively short, and finally The heat taken away is 80%-85% of the total ...

Examples

Embodiment 1

[0009] A cooling process of the Czochralski single crystal method. After the cooling stage is carried out for 0.8 hours, the temperature in the furnace drops to 1220 ° C and the pressure is 30 Pa. Stop feeding argon into the furnace and turn off the vacuum pump to form a In the pressure-holding state, the pressure is 50 Pa, and it is maintained for 4.2 hours until the whole Czochralski method single crystal preparation process ends.

Embodiment 2

[0011] A cooling process of the Czochralski single crystal method. After the cooling stage is carried out for 1.0h, the temperature in the furnace drops to 1250°C and the pressure is 32Pa. Stop feeding argon into the furnace and turn off the vacuum pump to form a In the pressure-holding state, the pressure is 53 Pa, and it is maintained for 4.5 hours until the whole Czochralski method single crystal preparation process ends.

Embodiment 3

[0013] A cooling process of the Czochralski single crystal method. After the cooling stage is carried out for 1.2 hours, the temperature in the furnace drops to 1280 ° C and the pressure is 34 Pa. Stop feeding argon into the furnace and turn off the vacuum pump to form a In the pressure-holding state, the pressure is 56 Pa, and it is maintained for 4.8 hours until the whole Czochralski method single crystal preparation process ends.