Silicon purification method and silicon purification device

Abstract

The silicon purification method uses a silicon purification device including at least a crucible for loading a silicon metal and a plasma torch, and purifies the silicon metal by injecting a plasma gas from the plasma torch toward a melt surface of the silicon metal loaded in the crucible in a state where an angle formed by the melt surface and the plasma gas is set in the range of 20° to 80°.

What is claimed is: 
     
         1 - 6 . (canceled) 
     
     
         7 . A silicon purification device comprising:
 a crucible for loading a silicon metal; and   a plasma torch having an angle-controlling unit that controls a direction of a plasma gas, said plasma torch injecting the plasma gas to a melt surface of the silicon metal loaded in the crucible.   
     
     
         8 . The silicon purification device according to  claim 7 , further comprising
 a plurality of plasma torches, wherein   the plasma torches are arranged such that, by injecting plasma gases from the respective plasma torches, a plurality of recesses is formed on the melt surface, and a circulation flow is caused along the recesses.   
     
     
         9 . The silicon purification device according to  claim 8 , wherein directions of nozzle ports of the plasma torches are aligned in a forward direction of the circulation flow. 
     
     
         10 . The silicon purification device according to  claim 7 , further comprising a plurality of plasma torches, wherein
 nozzle ports of the plasma torches are arranged such that a virtual circle A having, on a circumference thereof, a plurality of recesses formed on the melt surface by injecting plasma gases from the plasma torches is concentric with a virtual circle F having, on a circumference thereof, points obtained by projecting the nozzle ports of the plasma torches on the melt surface.   
     
     
         11 . The silicon purification device according to  claim 10 , wherein directions of the nozzle ports of the plasma torches are aligned in any one of a clockwise direction and a counterclockwise direction of the concentric circles. 
     
     
         12 . The silicon purification device according to  claim 7 , wherein an angle formed by the melt surface of the silicon metal loaded in the crucible and a direction of the nozzle port of each of the plasma torches is set in the range of 20° to 80°. 
     
     
         13 . The silicon purification device according to  claim 7 , further comprising:
 a supplying port for a plasma working gas, and a supplying port for an oxidation gas different from said supplying port for the plasma working gas at positions near the nozzle port of the plasma torch.   
     
     
         14 - 16 . (canceled) 
     
     
         17 . A silicon purification device for purifying silicon comprising:
 a plasma torch including a nozzle port, a supplying port for a plasma working gas, and a supplying port for steam different from the supplying port for the plasma working gas at positions near the nozzle port of the plasma torch;   wherein said plasma torch is configured to inject a plasma gas from the plasma torch toward a melt surface of the silicon metal loaded in the crucible to purify the silicon metal, and   wherein said plasma torch is further configured to adjust an amount of steam supplied by the supplying port for steam to control a melt temperature of the silicon metal to be in the range of 1700° C. to 1900° C.   
     
     
         18 - 20 . (canceled) 
     
     
         21 . A silicon purification device for purifying silicon comprising:
 a plasma torch including a nozzle port configured to inject a plasma gas toward a melt surface of the silicon metal loaded in the crucible to purify the silicon metal, and   a driving unit configured to keep constant a distance from a center of a top end of the nozzle port to the melt surface in a direction of the plasma gas injected from the nozzle port.   
     
     
         22 . The silicon purification device according to  claim 21 , further comprising
 a supplying port for a plasma working gas, and a supplying port for an oxidation gas different from the supplying port for the plasma working gas at positions near the nozzle port.