Oxygen content increasing mechanism in Czochralski (CZ) silicon crystals doped with heavy antimony under a double-typed heat shield

► Effect of a heat shield geometry on the oxygen concentration has been investigated experimentally and numerically. ► Melt-flow patterns come from the competition between thermal buoyancy force around the crucible wall and centrifugal force from the seed rotation. ► Sizes of melt-flow patterns usually depend on the operation conditions. ► Under single-typed heat shield the high rotation rates allow the single crystal yield increased apparently while the oxygen concentration is kept unchanged. ► Under double-typed heat shield even at the low rotation rates oxygen content as well as the single crystal yield is augmented.