Method for cleaning polysilicon
AssigneeMitsubishi Materials Silicon Corporation
InventorKenji Hori
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Abstract
A method for cleaning polysilicon comprises steps of cleaning solid or granular polysilicon with an aqueous solution of dissolved ozone, and of cleaning with hydrofluoric acid the polysilicon receiving the above cleaning based on an aqueous solution of dissolved ozone, wherein the above steps are executed once in this order, or the above steps are repeated once or more in this order. Subsequent to the last cleaning step using hydrofluoric acid, a still other step of cleaning the polysilicon with pure water and then drying it is preferably added. This method for cleaning polysilicon allows organic materials, particles and metal impurities adsorbed on the surface of polysilicon to be removed at a low cost, and to increase the freeing rate.
Claims5
A method for cleaning solid or granular polysilicon to serve as a material for manufacturing a single crystal by melting and polysilicon in a quartz crucible, immersing a crystal seed into the thus obtained melt used raising the crystal seed, comprising steps of cleaning said polysilicon with an aqueous solution of dissolved ozone, and of cleaning with hydrofluoric acid the polysilicon which has undergone the cleaning stop using the aqueous solution of dissolved ozone, wherein the cleaning stop using an aqueous solution of dissolved ozone comprises the steps of jointing an aqueous solution of dissolved ozone at said polysilicon contained in a chemically resistant basket and immersing the basket containing the polysilicon in an aqueous solution of dissolved ozone, and the above steps are executed once in this order, or the above steps are repeated once or more in this order.
Dependencies are inferred from the claim text.