DEVICE FOR PULLING UP SINGLE CRYSTAL

摘要

PURPOSE:To provide a device for pulling up especially a large-diameter and high-quality single crystal with the controlled oxygen concn. and uniform oxygen distribution (ORG) in the wafer plane and with uniform oxygen concn. in the axial direction. CONSTITUTION:A flow straightener 2 has an outer diameter (d) smaller than the inner diameter D of a crucible 3 and consists of a cylindrical part 4 extending almost vertically along the flow direction of a descending carrier gas G, a reduced-diameter part 6 contracted from the lower end of the cylindrical part 4 and forming a lower gap 5 with a pulled up single crystal S and a detaining part 7 forming an upper gap 18 outside the straightener 2 by partially supporting the straightener 2 in a pulling-up chamber 1. The carrier gas passage is separated by the straightener 2 into a first passage P1 for the carrier gas branched at the upper end of the cylindrical part 4 and extending into the cylindrical part 4 and the second passage P2 in which the carrier gas G passes through the lower gap 5 from the first passage P1 and then between the molten material surface and the straightener 2, branches at the upper part of the cylindrical part 4 and passes through the upper gap 18.