Method for producing a polycrystalline silicon, polycrystalline silicon and solar cell

Abstract

Silicon raw material and gallium dopant are charged and mixed in a crucible. The silicon raw material is heated to a predetermined temperature, and melted under an inactive gas atmosphere. The melted silicon raw material is cooled down to be crystallized to make a polycrystalline silicon incorporating the gallium dopant.

1 . A method for producing polycrystalline silicon, comprising the steps of: 
 charging and mixing silicon raw material and gallium dopant in a crucible,    melting said silicon raw material under an inert gas atmosphere through heating to a predetermined temperature, and    cooling down said silicon raw material melted to be crystallized to make a polycrystalline silicon incorporating said gallium dopant.    
     
     
         2 . The producing method as defined in  claim 1 , wherein the content of said gallium dopant for said silicon raw material is set within 5×10 −4 -6.3×10 −2  atomic %.  
     
     
         3 . The producing method as defined in  claim 1 , wherein the cooling rate for said melted silicon raw material is set to 1° C./min or below.  
     
     
         4 . The producing method as defined in  claim 1 , wherein oxygen-including compound is added to said silicon raw material, in addition to said gallium dopant.  
     
     
         5 . The producing method as defined in  claim 4 , wherein said oxygen-including compound is silicon oxide.  
     
     
         6 . The producing method as defined in  claim 4 , wherein the oxygen content of said polycrystalline silicon is set within 10 16 -10 18 /cm 3 .