Method for determining and regulating a diameter of a single crystal during pulling of the single crystal

摘要

The diameter (d_K) of a cylindrical section and of an end cone of a single crystal being pulled from a melt in a crucible, is determined by measuring the diameter (d_K) of the single crystal at an interface with the melt while taking into account a lowering rate (v_s) of a surface of the melt relative to the crucible, a lifting rate (v_K) with which the crystal is raised relative to the crucible, and a conservation of mass, wherein a diameter of a cylindrical section of the single crystal, determined by means of observing a bright ring on the surface of the melt, and is used for a correction, a plausibility check or a comparison of the diameter (d_K) of the single crystal.