To produce a single crystal excellent in oxide film dielectric strength characteristics by simply performing the temp. gradient control of a semiconductor single crystal grown with a CZ (Czochralski) method and particularly inhibiting the generation of as-grown defects.
In this device, a shielding cylinder placed so as to encircle single crystal silicon 7 during pulling-up is divided into a first shielding cylinder section 4, a second shielding cylinder section 5 and a third shielding cylinder section 6 to form a telescopic shielding cylinder. A wire 8 wound around a wind-up reel 10 is fastened to the third shielding cylinder section 6 to extend/contract the shielding cylinder by rotating the wind-up reel 10. Also, the first shielding cylinder section 4 is fixed to elevating/lowering rods 3 to elevating/lowering the shielding cylinder by vertically moving the rods 3. At the time of pulling up the single crystal silicon 7, an optional part of the shielding cylinder is contracted by driving the wind-up reel 10 to subject a specific region of the single crystal silicon 7 to heat insulation by using overlapping parts of the shielding cylinder with each other and to reduce the temp. gradient of the single crystal silicon 7 at the time of passing it through the temp. region of 1,200 to 1,000°C.
KUBOTA TOSHIMICHI
KOTOOKA TOSHIROU
KAMOGAWA MAKOTO
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