Patent ID: 8679251

Claim:
An apparatus for growing a silicon single crystal from a melt, comprising: a crucible for holding the melt; a magnetic system imposing a horizontal magnetic field on the melt, the magnetic field having a magnetic induction B at a field center C; a heat shield surrounding the silicon single crystal, the heat shield having a lower end which is connected to a bottom cover of the heat shield facing a free surface of the melt and having a non-axisymmetric shape with respect to a center axis M of the crucible, the shape of the bottom cover forcing a gas which is directed between the silicon single crystal and the heat shield to the free surface of the melt to flow over a region of the free surface of the melt in a direction substantially perpendicular to the magnetic induction B, wherein the bottom cover comprises a ring section which is surrounded by a brim section and a collar section, the brim section and the collar section forming a channel which has an opening for directing the gas over the region of the free surface of the melt.