Abstract: In appropriate setting of magnetic field applied to a molten silicon 12 stored in a cylindrical quartz crucible 11, the maximum value B0 of magnetic flux density on a vertical symmetric axis 17 as a cylindrical axis of the quartz crucible 11 in horizontal magnetic field generated by a pair of exciting coils 13 and 14 calls B0. On circle at which horizontally symmetric plane 18 traversing and perpendicular to a vertically symmetric axis 17 becoming magnetic flux B0 crosses an inner diameter of the quartz crucible 11, the minimum value of magnetic flux density calls Bmin, and the maximum value of magnetic flux density calls Bmax. Those magnetic flux densities B0, Bmin and Bmax are adjusted to be given ranges, and upward flow and temperature of a molten silicon 12 at the lower part of a solid-liquid interface 15a are appropriately controlled.

Abstract: A single crystal pulling apparatus having a heater 4 melting material silicon by thermal radiation from a cylindrical exothermic part 4a which surrounds a crucible 3 inside a furnace body 2 and an electromagnet 13 which is prepared to surround the furnace body 2 and applies a transverse magnetic field to the silicon liquid melt in the crucible 3 is provided. A length h in a pull-up axis direction in the exothermic part 4a of the heater 4 is arranged to be 0.5 times to 0.9 times an inner diameter of the crucible 3, a first middle position in the pull-up axis direction in the exothermic part 4a is arranged below a second middle position in the pull-up axis direction in the electromagnet 13, and a distance difference d between the first and second middle positions is 0.15 times to 0.55 times the inner diameter R of the crucible 3.

Abstract: A single crystal pulling apparatus having a heater 4 melting material silicon by thermal radiation from a cylindrical exothermic part 4a which surrounds a crucible 3 inside a furnace body 2 and an electromagnet 13 which is prepared to surround the furnace body 2 and applies a transverse magnetic field to the silicon liquid melt in the crucible 3 is provided. A length h in a pull-up axis direction in the exothermic part 4a of the heater 4 is arranged to be 0.5 times to 0.9 times an inner diameter of the crucible 3, a first middle position in the pull-up axis direction in the exothermic part 4a is arranged below a second middle position in the pull-up axis direction in the electromagent 13, and a distance difference d between the first and second middle positions is 0.15 times to 0.55 times the inner diameter R of the crucible 3.

Abstract: In a Czochralski method for producing a silicon single crystal by growing the crystal, the pulling rate of the single crystal is gradually increased during formation of a tail part after formation of a predetermined or constant diameter part of the single crystal. The length t of the tail part is defined to be a or more, where a represents a distance from the tip end of the tail part to a position of an extraordinary oxygen precipitation area when the tail part is formed after the predetermined or constant diameter part is grown. Productivity and yield of the silicon single crystal are improved by preventing rapid change in temperature while the single crystal is separated from the melt in the tailing process, to suppress generation of an area where the amount of precipitated oxygen is extraordinarily large and an OSF ring due to rapid increase in temperature when the tail part is formed, in the predetermined or constant diameter part near the tail part.

Abstract: A method for controlling an oxygen concentration of a single crystal which is pulled up in a Czochralski-method type single crystal pulling apparatus having a hermetical chamber in which the single crystal is pulled up and an inert gas supply and exhaust system by means of which an inert gas is supplied to the hermetical chamber and exhausted therefrom; the method being characterized in that the pneumatic pressure in the hermetical chamber and the supply rate of the inert gas are controlled in accordance with a prepared control pattern with respect to the proportion of the length of the as-grown crystal to the aimed final length thereof or with respect to the passage of time.