Patent ID: 7077905
Filing Date: 2006-07-18
Classification: C30B,Y10T

Abstract:
1. An apparatus for pulling a single crystal comprising a chamber, a crucible located in the chamber, a heater for heating a material provided in the crucible so that the material is melted, a radiation shield arranged in the chamber so as to surround a region in which a single crystal is pulled, for regulating flow of inert gas introduced therein, wherein a seed crystal is immersed into the melted material to pull the single crystal, the radiation shield comprises a graphite based material coated with silicon carbide, the radiation shield comprising a main shield body, a horizontal part, and a rising part, the main shield body being arranged so as to surround the single crystal and comprising a hollow pipe shape, the horizontal part extending inward and substantially horizontally, relative to a surface of the melt material, from the main shield body and comprising a ring shape, wherein the rising part rises upward along the single crystal and comprises a ring shape, a first curvature formed between the main shield body and the horizontal part, a second curvature formed between the horizontal part and the rising part, wherein each of the first curvature and the second curvature comprises an inside corner with a curved surface, a mounting part extending outward from an upper end of the main shield body, the mounting part comprises a ring shape, and a third curvature with a curved surface, which is formed between the main shield body and the mounting part, wherein each curved surface of the first, second and third curvatures is formed of a circular arc or an elliptic arc in cross section, and has a radius of curvature of 5 mm or more.