Susceptor Designs for Silicon Carbide Thin Films

Abstract

A susceptor is disclosed for minimizing or eliminating thermal gradients that affect a substrate wafer during epitaxial growth. The susceptor includes a first susceptor portion including a surface for receiving a semiconductor substrate wafer thereon, and a second susceptor portion facing the substrate receiving surface and spaced from the substrate-receiving surface. The spacing is sufficiently large to permit the flow of gases therebetween for epitaxial growth on a substrate on the surface, while small enough for the second susceptor portion to heat the exposed face of a substrate to substantially the same temperature as the first susceptor portion heats the face of a substrate that is in direct contact with the substrate-receiving surface.

1 . A susceptor for minimizing or eliminating thermal gradients across a substrate wafer, said susceptor comprising:
 a first susceptor portion formed of a material that is thermally responsive to electromagnetic radiation and having a top surface for receiving a semiconductor substrate wafer thereon; and   a second susceptor portion parallel to and spaced apart from said wafer-receiving surface of said first susceptor portion and formed of a material that is thermally responsive to electromagnetic radiation, said spacing being sufficiently large to permit the flow of gases therebetween for epitaxial growth on a substrate wafer on said surface, while small enough for said second susceptor portion to heat the exposed face of a substrate wafer to substantially the same temperature as said first suseeptor portion heats the face of a substrate wafer that is in direct contact with said substrate-receiving surface.   
   
   
       2 . The susceptor according to  claim 1 , wherein said first and second susceptor portions are horizontally oriented. 
   
   
       3 . The susceptor according to  claim 1 , wherein said first and second susceptor portions are formed of the same material and are responsive to the same frequencies of electromagnetic radiation. 
   
   
       4 . The susceptor according to  claim 1 , wherein said first and second susceptor portions are thermally responsive to radio frequency electromagnetic radiation. 
   
   
       5 . The susceptor according to  claim 1 , wherein said first susceptor portion is formed of graphite coated with silicon carbide, 
   
   
       6 . The susceptor according to  claim 1 , wherein said second susceptor portion is formed of graphite coated with silicon carbide. 
   
   
       7 . The susceptor according to  claim 1 , wherein said top surface of said first susceptor portion includes a plurality of wafer pockets. 
   
   
       8 . A susceptor for minimizing or eliminating thermal gradients across a substrate wafer, said susceptor comprising horizontally oriented first and second susceptor portions, wherein:
 said first susceptor portion is formed of graphite coated with silicon carbide that is thermally responsive to electromagnetic radiation and has a top surface including a plurality of wafer pockets for receiving a plurality of semiconductor substrate wafers; and   said second susceptor portion is parallel to and spaced above said wafer-receiving surface of said first susceptor portion and is formed of graphite coated with silicon carbide that is thermally responsive to electromagnetic radiation, said spacing being sufficiently large to permit the flow of gases therebetween for epitaxial growth on a substrate wafer on said surface, while small enough for said second susceptor portion to heat the exposed face of a substrate wafer to substantially the same temperature as said first susceptor portion heats the face of a substrate wafer that is in direct contact with said substrate-receiving surface.   
   
   
       9 . A chemical vapor deposition system comprising:
 a reaction vessel;   a gas supply system in fluid communication with said reaction vessel;   a source of electromagnetic radiation; and   a susceptor within said reaction vessel and comprising a first susceptor portion formed of a material that is thermally responsive to selected frequencies of electromagnetic radiation and having a top surface for receiving semiconductor substrate wafers thereon; and a second susceptor portion parallel to and spaced apart from said wafer-receiving surface of said first susceptor portion and formed of a material that is thermally responsive to selected frequencies of electromagnetic radiation, said spacing being sufficiently large to permit the flow of gases therebetween for epitaxial growth on a substrate wafer on said surface, while small enough for said second susceptor portion to radiantly and directly heat the exposed face of a substrate wafer to substantially the same temperature as said first susceptor portion heats the face of a substrate wafer that is in direct contact with said substrate-receiving surface to thereby minimize or substantially eliminate radial and axial temperature gradients across a substrate wafer.   
   
   
       10 . The system according to  claim 9 , wherein said first and second susceptor portions are horizontally oriented. 
   
   
       11 . The system according to  claim 9 , wherein said first and second susceptor portions are formed of the same material and are responsive to the same frequencies of electromagnetic radiation. 
   
   
       12 . The system according to  claim 9 , wherein said first and second susceptor portions are thermally responsive to radio frequency electromagnetic radiation. 
   
   
       13 . The system according to  claim 9 , wherein said first susceptor portion is formed of graphite coated with silicon carbide. 
   
   
       14 . The system according to  claim 9 , wherein said second suseeptor portion is formed of graphite coated with silicon carbide. 
   
   
       15 . The system according to  claim 9 , wherein said top surface of said first susceptor portion includes a plurality of wafer pockets. 
   
   
       16 . The system according to  claim 9 , wherein said source of electromagnetic radiation is inside said reaction vessel. 
   
   
       17 . The system according to  claim 9 , wherein said reaction vessel is formed of a material substantially transparent to electromagnetic radiation. 
   
   
       18 . The system according to  claim 17 , wherein said reaction vessel is made of quartz. 
   
   
       19 . The system according to  claim 9 , wherein said reaction vessel is made of stainless steel. 
   
   
       20 . The system of  claim 9 , wherein said gas supply system comprises an injector oriented substantially perpendicular to surface for receiving semiconductor substrate wafers thereon of said first susceptor portion. 
   
   
       21 . A chemical vapor deposition system comprising:
 a reaction vessel formed of a material substantially transparent to electromagnetic radiation;   a gas supply system in fluid communication with said reaction vessel;   a source of electromagnetic radiation; and   a susceptor within said reaction vessel and comprising a first susceptor portion formed of graphite coated with silicon carbide that is thermally responsive to selected frequencies of electromagnetic radiation and having a top surface including a plurality of wafer pockets for receiving a plurality of semiconductor substrate wafers; and a second susceptor portion parallel to and spaced apart from said wafer-receiving surface of said first susceptor portion and formed of graphite coated with silicon carbide that is thermally responsive to selected frequencies of electromagnetic radiation, said spacing being sufficiently large to permit the flow of gases therebetween for epitaxial growth on a substrate wafer on said surface, while small enough for said second susceptor portion to radiantly and directly heat the exposed face of a substrate wafer to substantially the same temperature as said first susceptor portion heats the face of a substrate wafer that is in direct contact with said substrate-receiving surface to thereby minimize or substantially eliminate radial and axial temperature gradients across a substrate wafer.