Abstract: A method of producing a Czochralski-grown silicon single crystal stably and efficiently with high production yield comprises the steps of setting pulling conditions such that at least a portion of a growing silicon single crystal having a temperature in excess of 1150.degree. C. is spaced upwardly from a surface of silicon melt by a distance greater than 280 mm; and pulling the growing silicon single crystal upward while maintaining the pulling conditions. The silicon single crystal produced by this method has an excellent oxide film dielectric breakdown strength. An apparatus for carrying out the method is also disclosed.

Abstract: A conical portion growth control method and an apparatus used in the method grow a conical portion 32B of a single crystal rod 32 by pulling the crystal rod from a melt 16 heated by a heater 14 in the Czochralski method, and aim to enhance reproducibility of the shape of the conical portion 32B and shorten the conical portion 32B. The control method has the steps of presetting a target value pattern 66 of the temperature of a concave portion 46 formed on a heat-insulating material 18 and a target value pattern 64 of the diameter change rate of a growing portion of the crystal rod, measuring the diameter of the crystal growing portion, calculating the change rate of the diameter, measuring the temperature of the concave portion, correcting the target temperature based on a difference between the calculated value and the target value of the diameter change rate, and controlling the amount of electricity supplied to the heater so that the measured temperature becomes equal to the corrected target temperature.

Abstract: Used in an apparatus for pulling a Si single crystal 36 up from Si molten liquid 35 by using the Czochralski method. In order to produce a Si single crystal having a desired quality, the diameter of the Si single crystal is controlled by controlling the pull-up speed of the Si single crystal, the sum of a reference temperature set value T.sub.B (X), which is a function of a pull-up distance X of the Si single crystal from a certain growth point, and a value proportional to a diameter deviation .DELTA.D is regarded as a reference temperature, and electric power supplied to a heater (24) for heating the Si molten liquid is controlled so that the temperature of the vicinity of the heater is equal to the reference temperature.