METHOD AND APPARATUS FOR MANUFACTURING SINGLE CRYSTALS

摘要

The invention provides a method and an apparatus for manufacturing single crystals wherein the weight of the single crystal pulled is measured by a weight detector. The measured weight is compared with a reference weight signal which is generated from a reference weight signal generator. A weight deviation signal representing a difference between these two signals is generated by a weight deviation detector. The weight deviation signal is differentiated by a first differentiation circuit and a differentiation output signal obtained is corrected for compensation for the buoyancy of the liquid encapsulant by a signal which is generated by a buoyancy correction signal generator. A corrected signal thus obtained is differentiated by a second differentiation circuit and is thereafter added to the corrected signal. The addition result is phase-compensated by a phase-compensating circuit. The phase-compensated signal is supplied to a heating control circuit. At the same time, the heating control circuit generates a heating control signal to a heating device in response to a program signal which is generated from a program signal generator. In response to the output signal from the heating device, a heater which controls the temperature of the melt held in a vessel and which is arranged outside the vessel is heated according to the program.