Patent ID: 7922990

Claim:
A method for the production of granulated polycrystalline silicon comprising depositing a reaction gas containing a gaseous silicon compound as silicon metal on silicon particles in a reaction zone of a fluidized bed reactor with a hot surface at a reaction temperature of from 600 to 1100° C., the silicon particles fluidized by means of a fluidizing gas to form a fluidized bed, and removing silicon particles with deposited silicon from the reactor together with unreacted reaction gas and fluidizing gas, wherein a gas composition containing from 99.5 to 95 mol. % of hydrogen and from 0.5 to 5 mol. % of the gaseous silicon compound is present on the surface of the reactor, the surface of the reactor is at a temperature of from 700 to 1400° C. which is at the temperature of the silicon particles or is higher than the temperature of the silicon particles in the reaction zone, the reactor containing 15-60 mol % gaseous silicon compound and 40-85 mol % hydrogen based on the total amounts of gaseous silicon compound gas and hydrogen gas in the reactor, and a reactor space inward from the surface of the reactor and within the reaction zone containing 20 mol % to 80 mol % gaseous silicon compound.