Reactor For Producing Polycrystalline Silicon and Method For Removing A Silicon-Containing Layer On A Component Of Such A Reactor

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.

What is claimed: 
     
         1 . A reactor for producing polycrystalline silicon, comprising a reactor vessel, a multiplicity of substrates of silicon within the reactor vessel for depositing polycrystalline silicon thereon, one or more reaction gas feed nozzles which feed silicon-containing reaction gas to the reactor vessel, an off-gas exit, an off-gas heat exchanger for cooling the reactor off-gas and a feed for feeding reactor off-gas and silicon-containing particles to the off-gas heat exchanger. 
     
     
         2 . The reactor of  claim 1 , wherein the reactor is a CVD reactor for producing polycrystalline silicon in rod form and the substrates are filament rods of silicon, further comprising a power supply which heats the filament rods by direct passage of current. 
     
     
         3 . The reactor of  claim 1 , wherein the reactor is a fluidized-bed reactor for producing granular polysilicon and the substrates are silicon seed particles, further comprising an inner reactor tube for containing a fluidized bed of granular polysilicon and a reactor base within the reactor vessel, a heater for heating the fluidized bed in the inner reactor tube, at least one bottom gas nozzle for feeding fluidizing gas, and at least one reaction gas nozzle for feeding reaction gas, a feed for feeding silicon seed particles, and a take-off conduit for a granular polysilicon product. 
     
     
         4 . The reactor of  claim 3 , further comprising a filter connected downstream of the off-gas heat exchanger for separating particles and gas. 
     
     
         5 . The reactor of  claim 3 , further comprising a cyclone connected downstream of the off-gas heat exchanger for continuous separation of particles from the reactor off-gas and which communicates with a feed for silicon-containing particles. 
     
     
         6 . The reactor of  claim 5 , further comprising a filter connected downstream of the cyclone for separating reactor off-gas dust.