Abstract: The invention relates to a method for producing highly pure, granular silicon by decomposing a gas containing silicon in a procedure comprising at least two operating states, at least one state comprising the increased formation of nucleus particles from the decomposition of said gas containing silicon and at least one other state comprising the increased separation of the silicon with expansion of the diameter of the silicon granules. The invention also relates to the use of silicon produced in this way and to highly pure, granular silicon particles which are characterised by a coreless structure.

Abstract: The invention relates to a method for producing hyper-pure granular silicon by decomposing a silicic gas in a reactor consisting of a metallic material. Said reactor is provided with a protective layer of silicon on the side thereof facing the product. The surface of the protective layer is continuously renewed by silicon deposition during the decomposition of the silicic gas, and the diffusion of impurities in the silicon produced is minimised to such an extent that high-purity silicon is obtained, suitable for use in the photovoltaic or semiconductor industry. The invention also relates to a reactor consisting of a metallic material and provided on the inside with a protective layer of silicon, the surface of said layer being continuously renewed during the operation of the reactor. The invention further relates to the use of the reactor for carrying out a method for producing high-purity granular silicon by decomposing a silicic gas.