Patent ID: 8043660

Claim:
A method for manufacturing polycrystalline silicon, in which a plurality of silicon seed rods stood in a reaction furnace is heated and polycrystalline silicon is deposited on surfaces of the silicon seed rods by a raw material gas ejected from gas ejection ports located in an inner bottom part of the reaction furnace, the method comprising: a stabilizing step of deposition wherein a velocity of ejecting the raw material gas from the gas ejection ports is gradually increased in a first stage of the deposition of the polycrystalline silicon; a shaping step wherein first the ejection velocity is increased at an increasing rate higher than that in the stabilizing step and then the ejection velocity is gradually increased at a rate lower than the increasing rate; and a growing step wherein, after the shaping step, the ejection velocity is made slower than that at the end of the shaping step.