METHOD FOR PULLING SILICON SINGLE CRYSTAL

摘要

PROBLEM TO BE SOLVED: To produce an ingot of a defect-free silicon single crystal containing oxygen in an controlled concentration with comparative ease and with relatively low consumption of electric power and in a relatively narrow space. SOLUTION: A quartz crucible 14 is rotated at a predetermined speed and the ingot 16 of the silicon single crystal is rotated at a predetermined speed. A first coil 11 and a second coil 12 are arranged at a predetermined interval in the vertical direction so that the rotation axis of the crucible 14 agrees with the center of each coil, and electric currents are made to flow through the coils in such a manner that the directions of the currents flowing through the coils 11 and 12 are reverse to each other. Thereby, cusped fields 17 passing through a neutral plane 17a between these coils are generated from the center of each coil. The ingot is pulled at a speed so that the inside of the ingot becomes a perfect zone. The position of the neutral plane 17a of the cusped fields 17, the intensity of the cusped fields 17, the speed of the rotation of the quartz crucible 14 and the speed of the rotation of the ingot 16 are controlled so that the shape of the solid-liquid interface 19 between the silicon melt 13 and the ingot 16 becomes convex upward.