15000C. According to the information about graphite heater, the temperature of graphite heater in Czochralski single crystal furnace is 15000℃. The solid massive polysilicon is put into a timely crucible in a single crystal furnace, and the polysilicon is heated and melted by a graphite heater in the single crystal furnace. The temperature in the furnace is as high as15000 C. After melting, the single crystal silicon rod is drawn through the processes of seeding, shouldering, equal diameter, ending and stopping the furnace. The whole process takes 40-60 hours, and the oxides of silicon and various dopants in molten silicon are constantly volatilized during the whole process.