Fluidized bed reactor and method of producing granular polysilicon
AssigneeWacker Chemie AG
InventorsSimon PEDRON, Gerhard FORSTPOINTNER
Life of this patent
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Abstract
The fluidized bed process for preparing polysilicon by chemical vapor deposition is improved by positioning at least one Laval nozzle upstream from a gas inlet into the reactor.
Claims10
-10. (canceled)
A fluidized bed reactor for producing granular polysilicon, comprising:
- a vessel having an inner reactor tube for a fluidized bed of granular polysilicon, and a reactor base;
- a heating device for heating the fluidized bed in the inner reactor tube;
- at least one opening in the reactor base for feeding fluidizing gas, and at least one opening in the reactor base for feeding reaction gas;
- a device for removing reactor offgas;
- a feed apparatus for feeding silicon seed particles;
- and a withdrawal conduit for granular polysilicon product, wherein a Laval nozzle is situated upstream of at least one of the openings in the reactor base, suitable for supercritically expanding at least one mass stream fed to the fluidized bed reactor.
A method for producing granular polysilicon in a fluidized bed reactor, comprising fluidizing silicon particles by means of a fluidizing gas that is fed via at least one opening in the reactor base of the fluidized bed reactor, forming a fluidized bed which is heated via a heater to a temperature of 850-1200° C., feeding a silicon-containing reaction gas via at least one opening in the reactor base of the fluidized bed reactor, and depositing silicon onto the silicon particles, wherein at least one mass stream of fluidizing gas or reaction gas fed to the fluidized bed reactor is expanded supercritically, by a Laval nozzle situated upstream of at least one of the openings in the reactor base which expands the at least one mass stream by overpressure prevailing in the Laval nozzle.
Dependencies are inferred from the claim text.