Seed crystal holder for pulling up single crystal and method of manufacturing silicon single crystal using the same

Abstract

A seed crystal holder for pulling up a single crystal is made of a carbon fiber-reinforced carbon composite material, and has a substantially cylindrical shape with a hollow space having a shape matching an outer shape of a substantially rod-shaped seed crystal. A direction of carbon fibers at a part in contact with at least an outer peripheral surface of the seed crystal has isotropy as viewed from a central axis of the hollow space.

What is claimed is: 
     
       1. A seed crystal holder for pulling up a single crystal that is made of a carbon fiber-reinforced carbon composite material and that has a substantially cylindrical shape with a hollow space having a shape matching the outer shape of a substantially rod-shaped seed crystal, including
 a core part in which a direction of carbon fibers has isotropy as viewed from a center axis of the hollow space; and 
 a clad part in which the direction of the carbon fibers has anisotropy as viewed from the center axis of the hollow space, wherein 
 the core part is provided at least at a part contacting an outer peripheral surface of the seed crystal. 
 
     
     
       2. The seed crystal holder as claimed in  claim 1 , wherein
 the direction of the carbon fibers constituting the core part has a circumferential direction component. 
 
     
     
       3. The seed crystal holder as claimed in  claim 2 , wherein
 the direction of the carbon fibers constituting the core part has a component parallel to the center axis. 
 
     
     
       4. The seed crystal holder as claimed in  claim 1 , comprising:
 a cylindrical upper section having a first hole diameter, 
 a cylindrical intermediate section positioned below the cylindrical upper section and being gradually reduced in diameter from the first hole diameter to a second hole diameter, and 
 a cylindrical lower section positioned below the cylindrical intermediate section and having the second hole diameter, wherein 
 the core part is provided at least in an inner peripheral side region of the cylindrical intermediate section, and 
 the clad part is provided in a region other than a formation region of the core part. 
 
     
     
       5. The seed crystal holder as claimed in  claim 4 , wherein
 the core part is provided in the cylindrical intermediate section and cylindrical lower section, and 
 the clad part is provided in the cylindrical upper section. 
 
     
     
       6. The seed crystal holder as claimed in  claim 4 , wherein
 the core part is provided in the inner peripheral side regions of the respective cylindrical upper section, cylindrical intermediate section, and cylindrical lower section, and 
 the clad part is provided in the outer peripheral side regions of the respective cylindrical upper section, cylindrical intermediate section, and cylindrical lower section. 
 
     
     
       7. The seed crystal holder as claimed in  claim 1 , wherein
 the core part is removable from the clad part.