Abstract: A method for measuring a diameter of a single crystal ingot pulled up in a single crystal pulling apparatus comprising: calculating the weight of the pulled-up single crystal, calculating the descent amount of the melt surface relative to the crucible wall from the calculated pulled-up weight of the grown single crystal, and then either correcting the value of the ingot diameter actually measured by the optical sensor in response to the descent amount of the melt surface level or raising the crucible by an amount equal to the descent amount of the surface level.

Abstract: A Czochralski-type single crystal pulling apparatus in which the heater device is adapted to shift vertically, and a control device is provided for controlling the vertical shifting of the heater and the crucible assembly in predetermined manners, of which a preferred manner is to control the vertical shifting of the heater and the crucible assembly such that the vertical velocities of the crucible assembly and the heater are in direct proportion to the vertical velocity of the pull means.

Abstract: Disclosed is a method of controlling the diameter of a single crystal produced by the Czochralski method. The diameter of a tapered portion of the single crystal is controlled by controlling the temperature of a melt in a crucible and the rotational speed of the crucible. The control range of the rotational speed of the crucible is made narrower as the diameter of the tapered portion approaches closer to that of a body portion, and the rotational speed is made constant while the body portion is grown.

Abstract: An apparatus is used in the production of a monocrystalline rod by Czochralski method and is adapted for measuring the diameter of the monocrystalline rod at the melt surface of the melt by processing image signal derived from an image sensor. The measurement of the diameter is conducted by determining the diameter of the monocrystalline rod at the melt surface by processing the output signal from the image sensor, and multiplying the rod image diameter with a function of the difference between the initial melt surface level and a melt surface corrected in accordance with a change in the temperature in the apparatus chamber or a change in the leval of the electrical power supplied to a heater for heating a crucible.

Abstract: A device for use in a monocrystal producing apparatus based on the FZ method and designed to detect a crystallization interface (20) between a melt (16) and a monocrystalline rod (12) even if the luminous line of the crystallization interface is partly curved downward. This device samples a series of luminance signals from the side of the melt to the side of the monocrystalline rod along a sensing line intersecting the crystallization interface, thereby successively outputs a series of sampled luminance signals (Sj), determines a value as a reference level (S.sub.0) relative to this specific level of the luminance signals, e.g., a peak value thereof, and discriminates the crystallization interface when one of the series of sampled luminance signals exceeds the reference level. A pixel position corresponding to this discrimination is determined as a pixel position corresponding to the crystallization interface.

Abstract: A load measuring device for measuring the pulling up load of a monocystalline rod (38) grown by the Czochralski method utilizes a strain gauge (20). The monocrystalline rod (38) is pulled up by wire rope (36) consisting of multiple strands. The pulley (34) guiding the wire rope between a drum (36) and a crystal holder (44) has a guide groove which has a cross-sectional shape which is substantially identical to a semicircle circumscribing the wire rope.

Abstract: A melt-surface initial position adjusting apparatus which is suitable for use in a monocrystal growing system employing the Czochralski method to adjust the vertical position of the melt surface before the growing of a monocrystal. The apparatus can ensure a highly precise measurement of a crystal-diameter measuring device, thereby enabling a reduction in the costs of producing a monocrystal bar. Before the growing of a crystal, the vertical position (H) of the surface (16A) of a melt within a crucible is measured. The crucible is moved vertically on the basis of the measured value in such a manner as to maintain the distance (L) between the melt surface (16A) and an image sensor (28) for measuring the crystal diameter at a predetermined value.

Abstract: An apparatus for measuring the diameter of a crystal in which an optical sensor scans along a sensing line which crosses at one point a luminous ring formed at the interface between a crystalline rod and a melt; the picture element position corresponding to a maximum luminance is discriminated when the optical sensor scans; the mean value of the picture element position is calculated over at least one revolution of the crystalline rod; and the diameter D of the crystalline rod at a portion thereof interfacing with the melt is calculated from the mean value and the level of the melt. Similarly, the minimum crystal diameter can be calculated by obtaining the picture element position corresponding to the minimum crystal diameter instead of obtaining the mean of the picture element position.