PRODUCTION OF HIGH-PURITY GRANULAR SILICON

PURPOSE:To obtain the dense silicon having a low void coefficient and a smooth outer surface, by evenly supplying a fluidization gas to the horizontal cross section of a fluidized-bed reactor packed with silicon crystal grains to fluidize the grains, and supplying silicon hydrides, etc., from the center part. CONSTITUTION:Silicon crystal grains are packed as seeds from a line 4 into the fluidized-bed reactor 6 made of the SiC, quartz, Si3N4, etc., with the contact part with the grains and gases coated with a high-purity silicon layer. A fluidization gas consisting of gaseous H2 and/or an inert gas such as Ar is introduced from a line 1 at the >=1.2 times supply velocity for the minimum fluidization velocity, and evenly supplied through a gas diffusing plate 7 to the horizontal cross section vertical to the gravitational direction to fluidize the grains. The grains are heated to 550-1,000 deg.C by a heater 10, silicon hydrides such as monosilane and/or disilane or the hydrides and gaseous H2 and/or an inert gas are supplied from a line 2 at the center part at the velocity higher than the terminal velocity of the largest silicon crystal grain, a reaction is initiated, and the titled silicon having 500-1,500mu grain diameter is obtained.