Abstract: A polycrystalline silicon rod comprises a seed rod made of polycrystalline silicon, and a polycrystalline silicon deposit which is deposited on the outer circumferential surface of the seed rod by the CVD process. A diameter of the polycrystalline silicon rod is 77 mm or less. When the polycrystalline silicon rod is observed by an optical microscope with respect to the cross section perpendicular to an axis of the seed rod, needle-shaped crystals each having a length of 288 ?m or less are uniformly distributed radially with the seed rod being as the center in the polycrystalline silicon deposit. The needle-shaped crystals account for 78% or more of the cross section.

Abstract: A polycrystalline silicon rod comprises a seed rod made of polycrystalline silicon, and a polycrystalline silicon deposit which is deposited on the outer circumferential surface of the seed rod by the CVD process. A diameter of the polycrystalline silicon rod is 77 mm or less. When the polycrystalline silicon rod is observed by an optical microscope with respect to the cross section perpendicular to an axis of the seed rod, needle-shaped crystals each having a length of 288 ?m or less are uniformly distributed radially with the seed rod being as the center in the polycrystalline silicon deposit. The needle-shaped crystals account for 78% or more of the cross section.

Abstract: A cylindrical grinder is disclosed that includes a support unit including an upper support device and a lower support device, in which an ingot of silicon single crystal is interposed in a direction of axis line between the upper support device and the lower support device and is clampingly held to be rotated around the axis line, and a grinding unit that relatively moves along the direction of axis line of the ingot to traverse grind an outer circumference of the ingot. The upper support device is placed at an upper position and the lower support device is placed at a lower position, so that the support unit clampingly holds the ingot in a state in which the direction of the axis line of the ingot is disposed along a vertical direction.

Abstract: A cylindrical grinder is disclosed that includes a support unit including an upper support device and a lower support device, in which an ingot of silicon single crystal is interposed in a direction of axis line between the upper support device and the lower support device and is clampingly held to be rotated around the axis line, and a grinding unit that relatively moves along the direction of axis line of the ingot to traverse grind an outer circumference of the ingot. The upper support device is placed at an upper position and the lower support device is placed at a lower position, so that the support unit clampingly holds the ingot in a state in which the direction of the axis line of the ingot is disposed along a vertical direction.

Abstract: A method of shoulder formation in growing silicon single crystals by the CZ method which comprises causing the taper angle to vary in at least two stages, desirably three stages or four stages, can inhibit the occurrence of dislocations in the shoulder formation step and thereby improve the yield and increase the productivity. As the number of stages resulting from varying the taper angle is increased, possible disturbances to occur at crystal growth interfaces and incur dislocations can be reduced and, further, when the above shoulder formation method is applied under application of a transverse magnetic field having a predetermined intensity, the occurrence of dislocations can be inhibited and defect-free silicon single crystals suited for the manufacture of wafers can be grown with high production efficiency. Therefore, the method is best suited for the production of large-diameter silicon single crystals with a diameter of 450 mm which are to be applied to manufacturing semiconductor devices.

Abstract: By giving a shoulder portion height of at least 100 mm in growing silicon single crystals having a diameter of 450 mm (weighing up to 1100 kg) by the CZ method, it becomes possible to inhibit the occurrence of dislocations in the shoulder formation step to thereby achieve a yield improvement and increase productivity. Furthermore, when this method is applied under application of a transverse magnetic field with a predetermined intensity, the occurrence of dislocations can be further inhibited and, accordingly, defect-free silicon single crystals suited for wafer manufacture can be grown with high production efficiency. Thus, the method is best suited for the production of large-diameter silicon single crystals having a diameter of 450 mm, which are applied in the manufacture of semiconductor devices.

Abstract: By providing a length of not less than 100 mm to a tail portion to be formed following the cylindrical body portion in growing silicon single crystals having a cylindrical body portion with a diameter of 450 mm using the CZ method, it becomes possible to inhibit the occurrence of dislocations in the tail portion and thus achieve improvements in yield and productivity. A transverse magnetic field having an intensity of not less than 0.1 T is preferably applied on the occasion of formation of that tail portion.