Patent ID: 7935327
Filing Date: 2011-05-03
Classification: C01B,Y02P

Abstract:
1. A process comprising: feeding a Siemens feed gas stream comprising silane or trichlorosilane in an amount of from 5 to 75 mol % to one or more Siemens reactors containing polycrystalline silicon seed rods; producing polycrystalline silicon in the one or more Siemens reactors and forming a vent gas stream having 20 to 50 mol % chlorosilanes; directly feeding the vent gas stream from the one or more Siemens reactors without intervening treatment steps to one or more fluidized bed reactors containing seed particles of silicon, where the temperature of the one or more fluidized bed reactors ranges from 900 to 1420° C., where residence time in the fluidized bed ranges from 0.5 to 2 seconds, and where polycrystalline silicon is produced in the one or more fluidized bed reactors.