Method for growing silicon single crystal

Abstract

A method for growing silicon single crystal uses as materials, silicon granules prepared by the silane process and having a residual hydrogen concentration of 7.5 wtppm or less, silicon granules prepared by the trichlorosilane process and having a residual chlorine concentration of 15 wtppm or less. In the case where such silicon granules are used, a bursting phenomenon does not occur when the silicon granules are melted. As a result, there is no scattered matter due to the bursting phenomenon, whereby the growth condition of the single crystal is not disturbed.

What is claimed is: 
     
       1. A method for producing silicon single crystal using silicon granules, comprising: preparing powdered silicon;   growing silicon granules by decomposing silane gas on the surface of said powdered silicon;   heating said silicon granules in an atmosphere of an inert gas so as to have a residual hydrogen concentration of 7.5 wtppm or less; and   growing silicon single crystal by pulling a silicon seed crystal from a melt of liquid silicon prepared by melting said silicon granules.   
     
     
       2. A method for producing silicon single crystal as set forth in claim 1, wherein in the step of growing silicon single crystal, said silicon granules are put in a crucible and melted, said silicon seed crystal is brought into contact with said melt of liquid silicon in said crucible, and said silicon single crystal growing at an end of with said seed crystal is pulled up together with said seed crystal. 
     
     
       3. A method for producing silicon single crystal as set forth in claim 1, wherein in the step of growing silicon single crystal, said silicon granules are supplied in a crucible as additional charge silicon materials. 
     
     
       4. A method for producing silicon single crystal as set forth in claim 3, wherein said silicon granules are supplied in said crucible as initial charge silicon materials. 
     
     
       5. A method for producing silicon single crystal as set forth in claim 1, wherein in the step of growing silicon single crystal, a bulkhead for dividing a crucible into an inner region and an outer region is provided in said crucible in the state that both regions communicate with each other under a surface of said liquid silicon, said silicon seed crystal is brought into contact with said liquid silicon in said inner region, said silicon granules are supplied into said outer region as additional charge silicon materials, and said silicon single crystal growing at an end of said seed crystal is pulled up together with said seed crystal. 
     
     
       6. A method for producing silicon single crystal as set forth in claim 5, wherein said silicon granules are supplied into said inner region of said crucible as initial charge silicon materials. 
     
     
       7. A method for producing silicon single crystal as set forth in claim 5, wherein said silicon granules are supplied into said outer region from plural positions in a circumferential direction of said crucible. 
     
     
       8. A method for producing silicon single crystal using silicon granules, comprising: preparing powdered silicon;   growing silicon granules by reducing trichlorosilane gas on the surface of said powdered silicon, wherein the growth rate of silicon is set to more than 0.4 m/min so as to have a residual chlorine concentration of 15 wtppm or less; and   growing silicon single crystal by pulling a silicon seed crystal from a melt of liquid silicon prepared by melting said silicon granules.   
     
     
       9. A method for producing silicon single crystal as set forth in claim 8, wherein in the step of growing silicon single crystal, said silicon granules are put in a crucible and melted, said silicon seed crystal is brought into contact with said melt of liquid silicon in said crucible, and said silicon single crystal growing at an end of said seed crystal is pulled up together with said seed crystal 
     
     
       10. A method for producing silicon single crystal as set forth in claim 8, wherein in the step of growing silicon single crystal, said silicon granules are supplied in said crucible as additional charge silicon materials. 
     
     
       11. A method for producing silicon single crystal as set forth in claim 10, wherein said silicon granules are supplied in said crucible as initial charge silicon materials. 
     
     
       12. A method for producing silicon single crystal as set forth in claim 8, wherein in the step of growing silicon single crystal, a bulkhead for dividing a crucible into an inner region and an outer region is provided in said crucible in the state that both regions communicate with each other under a surface of said liquid silicon, said silicon seed crystal is brought into contact with said liquid silicon in said inner region, said silicon granules are supplied into said outer region as additional charge silicon materials, and said silicon single crystal growing at an end of said seed crystal is pulled up together with said seed crystal. 
     
     
       13. A method for producing silicon single crystal as set forth in claim 12, wherein said silicon granules are supplied into said inner region of said crucible as initial charge silicon materials. 
     
     
       14. A method for producing silicon single crystal as set forth in claim 12, wherein said silicon granules are supplied into said outer region from plural positions in a circumferential direction of said crucible. .Iadd. 
     
     
       15.  A method for producing silicon single crystal using silicon granules comprising: preparing powdered silicon;   growing silicon granules by decomposing silane gas on the surface of said powdered silicon;   heating said silicon granules in a heating container to release the hydrogen included in the silicon granules as H 2  which is removed therefrom, said heating being carried out until the silicon granules have a residual hydrogen concentration of 7.5 wtppm or less; and   growing silicon single crystal by pulling a silicon seed crystal from a melt of liquid silicon prepared by melting said silicon granules. .Iaddend. .Iadd.   
     
     
       16.  The method of claim 15, wherein the H 2  is exhausted to outside of said heating container. .Iaddend.