Barrier coating for vitreous materials

Abstract

A chemical vapor deposition apparatus comprises a reaction chamber and one or more vitreous components having an outer surface that is covered at least in part by a devitrification barrier layer. In some arrangements, the one or more vitrious components can include a thermocouple. In a preferred arrangement, the devitrification barrier coating is formed from silicon nitride, which can be deposited on the vitreous component using chemical vapor deposition (CVD).

1 . A thermocouple configured for use in a chemical vapor deposition process chamber, said thermocouple comprising: 
 thermocouple wires;    a vitreous sheath surrounding the wires; and    a devitrification barrier coating covering at least a portion of said sheath.    
     
     
         2 . The thermocouple of  claim 1 , wherein said vitreous sheath is formed from quartz.  
     
     
         3 . The thermocouple of  claim 2 , wherein said devitrification barrier coating comprises silicon nitride.  
     
     
         4 . The thermocouple of  claim 1 , where said devitrification barrier coating has a thickness between about 1 and 10,000 angstroms.  
     
     
         5 . The thermocouple of  claim 4 , where said devitrification barrier coating has a thickness between about 50 and 5000 angstroms thick.  
     
     
         6 . The thermocouple of  claim 5 , where said devitrification barrier coating has a thickness between about 500 and 3,000 angstroms thick.  
     
     
         7 . The thermocouple of  claim 1 , where said devitrification barrier coating is formed from the group consisting silicon nitride, diamond, titanium nitride, titanium carbon nitride and combinations thereof.  
     
     
         8 . The thermocouple of  claim 1 , wherein said devitrification barrier coating covers an entire portion of said thermocouple.  
     
     
         9 . The thermocouple of  claim 1 , wherein devitrification barrier coating covers a portion of the thermocouple that is most susceptible to devitrification.  
     
     
         10 . The thermocouple of  claim 1 , wherein devitrification barrier coating covers a tip of said thermocouple.  
     
     
         11 . A method of minimizing divitrification in one or more vitreous components of a chemical vapor deposition process chamber, said method comprising the step of coating at least a portion of said one or more vitreous components with a barrier layer to protect said one or more vitreous components from processing gases in the chemical vapor deposition process chamber.  
     
     
         12 . The method of  claim 11 , wherein coating at least a portion of said one or more vitreous components with a barrier layer includes using chemical vapor deposition to form said barrier layer.  
     
     
         13 . The method of  claim 11 , wherein coating at least a portion of said one or more vitreous components includes forming the barrier layer from silicon nitride.  
     
     
         14 . The method of  claim 13 , wherein said step of forming the barrier layer out of silicon nitride includes using chemical vapor deposition to form said barrier layer.  
     
     
         15 . The method of  claim 13 , wherein said step of forming the barrier layer out of silicon nitride includes forming said barrier layer such that said barrier layer has a thickness between about 1 and 10,000 angstroms.  
     
     
         16 . The method of  claim 15 , wherein said step of forming the barrier layer out of silicon nitride includes forming said barrier layer such that said barrier layer has a thickness between about 500 and 3,000 angstroms thick.  
     
     
         17 . The method of  claim 11 , wherein coating at least a portion of said one or more vitreous components with a barrier layer includes forming the barrier layer from the group consisting of silicon nitride, diamond, titanium nitride, titanium carbon nitride, and combinations thereof.  
     
     
         18 . The method of  claim 11 , wherein coating at least a portion of said one or more vitreous components includes coating at least a portion of a thermocouple sheath.  
     
     
         19 . The method of  claim 18 , wherein coating at least a portion of said thermocouple includes coating a portion of the thermocouple sheath that is most susceptible to devitrification.  
     
     
         20 . The method of  claim 18 , wherein coating at least a portion of said thermocouple sheath includes covering a tip of said thermocouple sheath.  
     
     
         21 . The method of  claim 18 , wherein coating at least a portion of said thermocouple includes covering a portion of the thermocouple that is near a susceptor of said chemical vapor deposition process chamber.  
     
     
         22 . The method of  claim 11 , wherein coating at least a portion of said one or more vitreous components includes coating an entire portion of a thermocouple sheath.  
     
     
         23 . A chemical vapor deposition apparatus comprising a thermocouple, said thermocouple comprising thermocouple wires; a vitreous sheath surrounding the wires; and means for minimizing devitrification in said thermocouple.  
     
     
         24 . The apparatus of  claim 23 , wherein said means comprises a silicon nitride coating.  
     
     
         25 . A support device configured to support a susceptor in a chemical vapor deposition chamber, said support device including a plurality of arms, each of said arms having a distal end configured to directly contact and support said susceptor, said distal end being covered at least in part by a devitrification barrier coating.  
     
     
         26 . The support device of  claim 25 , wherein said support device includes three arms.  
     
     
         27 . The support device of  claim 25 , wherein said distal end comprises an upwardly extending projection.  
     
     
         28 . The support device of  claim 25 , wherein said distal end is formed from quartz.  
     
     
         29 . The support device of  claim 25 , wherein said devitrification barrier coating comprises silicon nitride.  
     
     
         30 . The support device of  claim 25 , where said devitrification barrier coating is formed from the group consisting silicon nitride, diamond, titanium nitride, titanium carbon nitride and combinations thereof.  
     
     
         31 . The support device of  claim 25 , wherein said devitrification barrier coating covers an entire portion of said distal end.