Corrosion and erosion resistant thin film diamond coating and applications therefor

Abstract

A thin film diamond coating is formed relatively slowly with a relatively low methane concentration and is identified by its Raman spectrographic characteristics. The thin film diamond, preferably 5 to 40 microns thick, provides substantially greater corrosion and erosion resistance in a corrosive environment than other thin film diamond coatings. It is believed that such thin film diamond coating is provided with enhanced chemical resistance due to its purity and quality.

1 . A protective coating for use on a surface of an article in a corrosive environment, consisting of: 
 a polycrystalline diamond film material made by chemical vapor deposition having a thermal conductivity greater than 1000 W/mK and a Raman Full Width at Half Maximum of less than 10 cm −1 , said diamond film material having a thickness not greater than 150 microns.    
     
     
         2 . A protective coating according to  claim 1 , wherein: 
 said diamond film material has a thickness between 5 and 40 microns.    
     
     
         3 . A protective coating according to  claim 1 , wherein: 
 said diamond film material is transparent to infrared radiation.    
     
     
         4 . A protective coating according to  claim 1 , wherein: 
 said diamond film material has a Raman Full Width at Half Maximum of less than 5 cm −1 .    
     
     
         5 . A protective coating according to  claim 1 , further comprising: 
 a dopant added to said polycrystalline diamond film material to increase its electrical conductivity.    
     
     
         6 . A protective coating according to  claim 5 , wherein: 
 said dopant is boron.    
     
     
         7 . An apparatus for processing a semiconductor wafer, comprising: 
 a) a processing chamber having an inner surface; and    b) a mandrel within said chamber and adapted to receive and hold the semiconductor wafer,    at least one of said inner surface and said mandrel including a protective coating comprising a polycrystalline diamond film material made by chemical vapor deposition having a thermal conductivity greater than 1000 W/mK and a Raman Full Width at Half Maximum of less than 10 cm −1 , said diamond film material having a thickness not greater than 100 microns.    
     
     
         8 . A apparatus according to  claim 7 , wherein: 
 said processing chamber includes a heat source and at least one window which is substantially transparent to heat from said heat source, at least a portion of said window being provided with said protective coating.    
     
     
         9 . A processing chamber according to  claim 7 , wherein: 
 said mandrel is adapted to rotate about an axis within said chamber.    
     
     
         10 . A processing chamber according to  claim 7 , wherein: 
 said protective coating has a Raman Full Width at Half Maximum of less than 5 cm −1 .    
     
     
         11 . An electrode, comprising: 
 a) an electrically conductive body;    b) a polycrystalline diamond film coating on said body, said coating having been made by chemical vapor deposition and having a thermal conductivity greater than 1000 W/mK and a Raman Full Width at Half Maximum of less than 10 cm −1 , said diamond coating having a thickness not greater than 40 microns; and    c) a dopant in said diamond coating for increasing its electrical conductivity.    
     
     
         12 . An electrode according to  claim 11 , wherein: 
 said polycrystalline diamond film has a Raman Full Width at Half Maximum of less than 5 cm −1 .    
     
     
         13 . A method of growing a thin film diamond coating which resists corrosion and erosion, said method comprising: 
 a) positioning a substrate element on a deposition mandrel in a processing chamber of a chemical vapor deposition (CVD) system    b) growing a diamond coating on said substrate to a thickness of between 5 and 150 microns, the diamond coating having a Raman Full Width at Half Maximum of less than 10 cm −1 , and    c) removing said substrate from said processing chamber.    
     
     
         14 . A method according to  claim 13 , wherein: 
 said substrate is maintained at a temperature of greater than 700° C.    
     
     
         15 . A method according to  claim 13 , wherein: 
 said diamond coating is grown at a rate of between 0.5 and 6.0 microns per hour.    
     
     
         16 . A method according to  claim 13 , wherein: 
 said diamond coating has a thermal conductivity greater than 1000 W/mK.    
     
     
         17 . A method according to  claim 13 , wherein: 
 said diamond coating has a Raman Full Width at Half Maximum of less than 10 cm −1 .    
     
     
         18 . A method according to  claim 13 , wherein: 
 said diamond coating has a Raman Full Width at Half Maximum of less than 5 cm −1 .