Abstract:
Contamination of fluidized bed-produced polycrystalline granules by phosphorus is reduced by employing as seals and/or packings, graphite containing
Abstract:
Silicon deposited by CVD and/or silico dust is removed from a polycrystalline silicon deposition reactor component by abrasion with silicon-containing particles in a gas stream.
Abstract:
A reactor for preparing granular polysilicon by deposition of polycrystalline silicon on silicon seed particles has a reaction vessel, an inner reactor tube for a fluidized bed comprising granular polysilicon and a reactor bottom within the reactor vessel, a heating device for heating the fluidized bed in the inner reactor tube, at least one bottom gas nozzle for introduction of fluidizing gas and at least one reaction gas nozzle for introduction of reaction gas, a feed device to introduce silicon seed particles, an offtake line for granular polysilicon, and a device for discharging reactor offgas from the reactor vessel, and has a cylindrical component which has openings on its cylindrical surface, with at least 5% and not more than 95% of the cylindrical surface being open located between the inner reactor tube and the heating device.
Abstract:
Yield of products of increased purity from a fluidized bed reactor where silicon is produced or consumed is enhanced by purging with inert gas, purging with hydrogen gas, and purging with a chlorosilane-containing gas. The purging with hydrogen is conducted at an elevated temperature.
Abstract:
Assembly of a fluidized bed reactor for the preparation of polycrystalline silicon granules by chemical vapor deposition of silicon onto seed particles and removal of polycrystalline silicon granules is facilitated without breakage and with gas tightness by a specific assembly sequence.
Abstract:
Granular polysilicon is produced in a fluidized-bed reactor by fluidizing silicon particles by means of a gas flow in a fluidized bed heated to a temperature of 850-1100° C., adding a silicon-containing reaction gas by means of a nozzle and depositing of silicon on the silicon particles, wherein, in at least 56% of an axially symmetric region around a nozzle opening of the nozzle,the reaction gas concentration is greater than 75% of the maximum concentration of the reaction gas (10 to 50 mol %),the fluidized-bed temperature is greater than 95% of the fluidized-bed temperature outside the axially symmetric region (850-1100° C.) andthe solids concentration is greater than 85% of the solids concentration at the edge of the fluidized bed (55 to 90% by volume).
Abstract:
Silicon deposited by CVD and/or silico dust is removed from a polycrystalline silicon deposition reactor component by abrasion with silicon-containing particles in a gas stream.