Annealing single crystal chemical vapor deposition diamonds

Abstract

A method to improve the optical clarity of CVD diamond where the CVD diamond is single crystal CVD diamond, by raising the CVD diamond to a set temperature of at least 1500 degrees C. and a pressure of at least 4.0 GPa outside of the diamond stable phase.

1 . A method to improve the optical clarity of CVD diamond where the CVD diamond is single crystal CVD diamond, by raising the CVD diamond to a set temperature of at least 1500 degrees C. and a pressure of at least 4.0 GPa outside of the diamond stable phase.  
   
   
       2 . The method of  claim 1  wherein, the CVD diamond is a single crystal coating upon another material.  
   
   
       3 . The method of  claim 1 , wherein the step of raising the temperature of the single crystal CVD diamond further comprises the step of: 
 raising the single crystal CVD diamond to a set temperature of about 1800 degrees C. to about 2900 degrees C.    
   
   
       4 . The method of  claim 1 , wherein the step of raising the temperature of the single crystal CVD diamond further comprises the step of: 
 maintaining the temperature of the single crystal CVD diamond at the set temperature for less than about one minute.    
   
   
       5 . The method of  claim 1 , wherein the step of raising the temperature of the single crystal CVD diamond further comprises the step of: 
 raising the temperature of the single crystal CVD diamond to at least 1500 degrees C. over a time period of about one minute to five minutes.    
   
   
       6 . The method of  claim 1 , wherein the step of raising the temperature of the single crystal CVD diamond comprises of the step of: 
 raising the temperature of the CVD diamond to about 2200 degrees C. at a pressure of about 5.0 GPa.    
   
   
       7 . The method of  claim 1 , further comprising the step of: 
 after reaching the set temperature, decreasing the temperature of the CVD to ambient temperature while maintaining the pressure on the single crystal CVD diamond.    
   
   
       8 . The method of  claim 1 , wherein the single crystal CVD diamond initially has a brown color and becomes colorless.  
   
   
       9 . The method of  claim 1 , further comprising the step of: 
 growing the single crystal brown diamond at a temperature of about 1400-1460 degrees C. in an atmosphere containing 4-5% N 2 /CH 4 .