| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technology for obtaining high purity polycrystalline silicon and recovering the heat generated in the production of the polycrystalline silicon, in a highly valuable state. <P>SOLUTION: The inner wall 11 of a reaction furnace 10 has a two-layer structure, wherein a corrosion-resistant layer 11a made of an alloy material having high corrosion resistance is formed in the inner side of the furnace to be in contact with a corrosive process gas, and a thermal conductive layer 11b is formed outside of the furnace (outer wall) so as to efficiently conduct the heat in the reaction furnace 10 from the inner wall surface to a coolant flow passage 13. The coolant flow passage has enough pressure resistance to allow hot water having the temperature equal to or higher than the standard boiling point to circulate. The corrosion-resistant layer 11a is made of an alloy material having such a composition that, when the percentages of mass contents of chromium (Cr), nickel (Ni) and silicon (Si) are denoted by [Cr], [Ni] and [Si], respectively, an R value defined by R=[Cr]+[Ni]-1.5[Si] is 40% or more. A precipitation reaction of polycrystalline silicon is carried out while the furnace inner surface temperature of the inner wall of the reaction furnace is controlled to 370°C or lower. <P>COPYRIGHT: (C)2011,JPO&INPIT |
