Patent ID: 8703248

Claim:
A polycrystalline silicon reactor in which an electric current is applied to a silicon seed rod provided within a furnace, thereby heating the silicon seed rod, a source gas supplied into the furnace is brought into reaction, and polycrystalline silicon is deposited on the surface of the silicon seed rod, comprising; at a bottom plate of the furnace, an electrode holder provided so as to be electrically insulated from the bottom plate, a seed rod holding electrode connected to the electrode holder, and holding the silicon seed rod upward, wherein a concavo-convex portions exposed to a furnace atmosphere is provided at an outer peripheral surface of the seed rod holding electrode, and a cylindrical lock nut screwed on the concavo-convex portion of the seed rod holding electrode and surrounding a portion of the seed rod holding electrode for fixing the seed rod holding electrode, wherein an upper end of the seed rod holding electrode is provided with a tapered portion whose width decreases upward, and the taper angle of the tapered portion is equal to or more than 70° and equal to or less than 130°, an outer surface of the seed rod holding electrode exposed to the furnace atmosphere is composed of the tapered portion and the concavo-convex portions, and a lower boundary of the tapered portion is directly connected with an upper boundary of the concavo-convex portions.