Process for producing polysilicon

摘要

Depositing (11) polycrystalline silicon on filaments in a deposition reactor by a reaction gas comprising hydrogen and a silicon-containing component, is claimed. The silicon-containing component exhibits a molar saturation of at least 25% with respect to hydrogen. An independent claim is also included for producing polysilicon, comprising (a) carrying out the above mentioned method, (b) supplying exhaust gas obtained from the deposition of the polycrystalline silicon, into a device for cooling the exhaust gas, which includes (i) supplying silicon tetrachloride containing condensed components of the exhaust gas obtained by cooling in the step (b), into a device for distillatively purifying (14) the condensate and (ii) supplying the non-condensed components resulting during cooling, into an adsorption or desorption unit (13), (c) obtaining a first material stream of non-condensing components purified by adsorption, which contains hydrogen, and (d) obtaining a second material stream of non-condensing components during regeneration of the adsorption unit by desorption and purging with a flushing gas, which contains silicon tetrachloride, and supplying the second material stream of non-condensing components to a converter for converting (15) silicon tetrachloride into trichlorosilane.