METHOD OF DETERMINING DIAMETER OF SINGLE CRYSTAL, PROCESS FOR PRODUCING SINGLE CRYSTAL USING SAME, AND DEVICE FOR PRODUCING SINGLE CRYSTAL

摘要

A method of determining the diameter length of a single crystal when the single crystal is pulled, in the Czochralski process, out of silicon melt held in a crucible.  The method for single-crystal diameter determination is characterized by using two cameras disposed apart from the single crystal at a distance not shorter than a desired diameter length of the straight part of the single crystal, which is being formed, so that the two cameras respectively face both ends of a diameter of the single crystal, the diameter being located at the single-crystal growth point, i.e., the contact between the single crystal and the melt surface.  The method is further characterized in that the cameras are used to take photographs of both ends of the single-crystal growth point from outside the furnace, and the diameter length of the single crystal is determined from the images obtained.  The diameter length of a single crystal is thus determined with improved accuracy.  Also provided are: a process for single-crystal production in which diameter length control is implemented with satisfactory accuracy on the basis of the results of the determination and a single crystal is industrially stably grown in a satisfactory yield; and a device for the production.