Method to convert waste silicon to high purity silicon
AssigneeSemlux Technologies, Inc.
InventorsAlleppey V. Hariharan, Jagannathan Ravi
Life of this patent
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Abstract
A process for the recovery of silicon includes providing silicon-containing solids recovered from a silicon manufacturing process, said recovered silicon-containing solids being substantially free of semiconductor dopants; converting the recovered silicon-containing solids into gaseous silicon forms; subjecting to purification by minimal distillation; collecting the gaseous silicon forms as a condensed liquid of silicon-containing compounds; and utilizing the silicon-containing compounds for silicon deposition.
Claims7
A method of processing silicon-containing powder recovered from a silicon manufacturing process, the method consisting essentially of:
- providing a high purity silicon powder recovered from a silicon manufacturing process-wherein said recovered high purity silicon powder has at least 99.999 wt % purity, less than 10 ppm metallic impurities, and has mean particle size of about 1-10 microns;
- converting the high purity silicon powder into trichlorosilane by a hydrochlorination reaction of said high purity silicon at a temperature of 200-250° C. by continuously providing a feed of a mixture of hydrogen chloride and hydrogen gases;
- and
- separating the nonvolatile metal chlorides and process HCl and H2 gases;
- and
- performing no more than one distillation-purification step on the trichlorosilane prior to converting the trichlorosilane to solar grade silicon and performing at least one or no more than two distillation-purification steps on the trichlorosilane prior to converting the trichlorosilane to electronic grade silicon.
Dependencies are inferred from the claim text.