METHOD FOR PRODUCING POLYCRYSTALLINE SILICON AND POLYCRYSTALLINE SILICON FOR SOLAR CELL PRODUCED BY THE METHOD

摘要

[Problems] Provided is a method for the preparation of polycrystalline silicon in which, in conducting preparation of polycrystalline silicon by the Siemens method or by the monosilane method, no outer heating means is necessitated for the core member (seed rod), onto which polycrystalline silicon is deposited, from the initial stage of heating, the deposition rate is high and the core member seed rod can be used repeatedly. [Means for solution] The method for deposition of high-purity polycrystalline silicon, at a high temperature, onto a white-heated seed rod in a closed reaction furnace by pyrolysis or hydrogen reduction of a starting silane gas supplied thereto, is characterized in that the seed rod is a member made from an alloy having a recrystallization temperature of 1200 °C or higher. It is preferable that the alloy member is of an alloy of Re-W, W-Ta, Zr-Nb, titanium-zirconium, or a carbon-added molybdenum (TZM) in the form of a wire member having a diameter of at least 0.5 mm, a plate member having a thickness of at least 1 mm or a prismatic member, or a tubular member having a diameter of at least 1 mm, wall thickness of at least 0.2 mm with an inner diameter not exceeding 5 mm, that the plate member, wire member, prismatic member or tubular member has a tapered form and further that the tubular member is a tapered duplex tube.