Halogen assisted physical vapor transport method for silicon carbide growth

Abstract

A physical vapor transport growth technique for silicon carbide is disclosed. The method includes the steps of introducing a silicon carbide powder and a silicon carbide seed crystal into a physical vapor transport growth system, separately introducing a heated silicon-halogen gas composition into the system in an amount that is less than the stoichiometric amount of the silicon carbide source powder so that the silicon carbide source powder remains the stoichiometric dominant source for crystal growth, and heating the source powder, the gas composition, and the seed crystal in a manner that encourages physical vapor transport of both the powder species and the introduced silicon-halogen species to the seed crystal to promote bulk growth on the seed crystal.

1 - 37 . (canceled) 
     
     
         38 . A system for bulk growth of silicon carbide, the system comprising:
 a crucible configured to receive a seed crystal and a silicon carbide source; and   an inlet for introducing a silicon-halogen gas composition into the crucible at a position in which the silicon-halogen gas composition can react with gas species generated by the silicon carbide source rather than directly with the silicon carbide source itself.   
     
     
         39 . A system according to claim  1 , wherein said inlet is proportionally large enough to direct a significant amount of the gas species to the growth zone while small enough to prevent extensive vapor loss from the silicon carbide source. 
     
     
         40 . A system according to claim  1 , further comprising a powder silicon carbide source, wherein the inlet extends into said crucible between the seed crystal and the powder silicon carbide source to facilitate reaction of the silicon halogen gas composition with vaporized species generated from the powder silicon carbide source. 
     
     
         41 . A system according to claim  4 , further configured to limit carbon-containing source gases to the gaseous species generated from the powder silicon carbide source. 
     
     
         42 . A system according to claim  4 , wherein a portion of the inlet extends into the crucible through the powder silicon carbide source. 
     
     
         43 . A system according to claim  4 , further configured for using a non-stoichiometric powder silicon carbide source and/or a powder silicon-rich source. 
     
     
         44 . A system according to claim  1 , wherein the crucible is graphite. 
     
     
         45 . A system according to claim  1 , further configured to receive 100 mm seed crystal. 
     
     
         46 . A system according to claim  1 , further comprising a source of silicon-halogen gas composition operably couplable to the inlet. 
     
     
         47 . A system for bulk growth of silicon carbide, the system comprising:
 a crucible configured to receive a seed crystal and a silicon carbide source separated from the seed crystal; and   an inlet extending into the crucible configured to introduce a silicon-halogen gas composition into said crucible;   the system configured to maintain the silicon-halogen gas composition in an amount that is less than the stoichiometric amount of silicon carbide source during bulk crystal growth.   
     
     
         48 . A system according to claim  10 , wherein said inlet is proportionally large enough to direct a significant amount of the species to the growth zone while small enough to prevent extensive vapor loss from the silicon carbide source. 
     
     
         49 . A system according to claim  10 , further comprising a powder silicon carbide source, wherein the inlet extends into said crucible between the seed crystal and the powder silicon carbide source to facilitate reaction of the silicon halogen gas composition with vaporized species generated from the powder silicon carbide source. 
     
     
         50 . A system according to claim  12 , wherein a portion of the inlet extends into the crucible through the powder silicon carbide source. 
     
     
         51 . A system according to claim  12 , further configured to limit carbon-containing source gases to the gaseous species generated from the powder silicon carbide source. 
     
     
         52 . A system according to claim  10 , further configured for using a non-stoichiometric powder silicon carbide source and/or a powder silicon-rich source. 
     
     
         53 . A system according to claim  10 , wherein the crucible is comprised of graphite. 
     
     
         54 . A system according to claim  10 , further configured to receive 100 mm seed crystal. 
     
     
         55 . A system according to claim  10 , further comprising a source of silicon-halogen gas composition operably couplable to the inlet. 
     
     
         56 . A system for bulk growth of silicon carbide, the system comprising:
 (i) a crucible; the crucible configured to:
 receive a powder graphite source capable of generating a gas species; 
 receive a seed crystal separated from the powder silicon carbide source; and 
   (ii) an inlet operably couplable to a source of silicon-halogen gas composition, the inlet having a portion extending into the crucible between the seed crystal and the powder silicon carbide source;   the system configured to facilitate reaction of the silicon halogen gas composition with vaporized species generated from the powder silicon carbide source.   
     
     
         57 . A system according to claim  19 , further configured to limit carbon-containing source gases to the gaseous species generated from the powder silicon carbide source. 
     
     
         58 . A system according to claim  19 , wherein a portion of the inlet extends into the crucible through the powder silicon carbide source. 
     
     
         59 . A system according to claim  19 , wherein the seed crystal is 100 mm.