Apparatus for the deposition of diamonds by microwave plasma chemical vapour deposition process and substrate stage used therein

Abstract

The present invention is related to an apparatus for the manufacture of gem grade diamonds. The apparatus has a plurality chambers ( 52 ) arranged in series to allow gas flow from a first chamber to a last chamber. Each chamber has a substrate stage assembly ( 10 ) to support a plurality of diamond seeds ( 19 ), a microwave generator ( 36 ) and a microwave source ( 38 ) to supply microwave energy into the chamber via a microwave arrangement ( 37 )). A gas supply ( 54 ) to supply gases to form the diamonds to the first chamber. The gases supplied to the first chamber are used in sequence with the gases exiting the first chamber becoming the input for a second chamber and then subsequent chambers in series. A vacuum pump is after the final vacuum chamber.

1 . An apparatus for the manufacture of diamonds, the apparatus comprising:
 a plurality of chambers, the chambers being arranged in a network such that each chamber is connected to an adjacent chamber so as to allow gas flow between the chambers, each chamber comprising a substrate stage assembly within the chamber to support a plurality of diamond seeds;   a gas supply to supply gases to form the diamonds into a first chamber; and   a microwave arrangement to supply microwave energy into the chamber,   whereby the gases supplied to the first chamber is used in sequence with the gas exiting the first chamber becoming the input for a second chamber and then subsequent chambers in the network.   
     
     
         2 . An apparatus as claimed in  claim 1 , wherein the chambers are arranged in a series in the network. 
     
     
         3 . An apparatus as claimed in  claim 1 , wherein the diamonds are gem grade diamonds. 
     
     
         4 . An apparatus as claimed in  claim 1 , wherein the microwave arrangement generates a 2.45 GHz microwave and directs the microwave energy into the vacuum chamber in the region of the substrate stage to form an oblate spheroidal plasma region. 
     
     
         5 . An apparatus as claimed in  claim 1 , wherein the substrate stage assembly comprises a substrate stage and a peripheral reflector. 
     
     
         6 . An apparatus as claimed in  claim 5 , wherein the substrate stage comprises
 a substantially circular planar base;   a peripheral raised edge to the base, the peripheral raised edge thereby defining a central recessed substrate receiving surface, the central recessed substrate receiving surface being substantially planar, the peripheral raised edge to the base comprising an inner edge and an outer edge, the inner edge comprising a bevel.   
     
     
         7 . An apparatus as claimed in  claim 6 , wherein the peripheral raised edge comprises an annular groove. 
     
     
         8 . An apparatus as claimed in  claim 7 , wherein the peripheral raised edge comprises an upper surface and a lower surface and the peripheral raised edge comprises an annular groove in at least one of the upper and lower surfaces. 
     
     
         9 . An apparatus as claimed in  claim 6  wherein the peripheral reflector comprises a cylindrical body around the substrate stage and the peripheral reflector is spaced laterally from the peripheral raised edge of the substrate stage. 
     
     
         10 . An apparatus as claimed in  claim 1  comprising more than two chambers in the network. 
     
     
         11 . An apparatus as claimed in  claim 2  comprising a vacuum pump in series after a final chamber. 
     
     
         12 . An apparatus for the manufacture of diamonds, the apparatus comprising:
 a plurality of chambers, the chambers being arranged in a network such that each chamber is connected to an adjacent chamber so as to allow gas flow between the chambers; and   a gas supply to supply gases to form the diamonds into a first chamber,   whereby the gases supplied to the first chamber is used in sequence with the gases exiting the first chamber becoming the input for a second chamber and then subsequent chambers in the network.   
     
     
         13 . An apparatus as claimed in  claim 12  wherein the chamber comprises a substrate stage assembly within the vacuum chamber to support a plurality of diamond seeds and a microwave arrangement to supply microwave energy into the chamber. 
     
     
         14 . An apparatus as claimed in  claim 12 , wherein the chambers are arranged in a series in the network. 
     
     
         15 . An apparatus as claimed in  claim 13 , wherein the microwave arrangement generates a 2.45 GHz microwave and directs the microwave energy into the vacuum chamber in the region of the substrate stage to form an oblate spheroidal plasma region. 
     
     
         16 . An apparatus as claimed in  claim 13  wherein the substrate stage assembly comprises a substrate stage and a peripheral reflector. 
     
     
         17 . An apparatus as claimed in  claim 16  wherein the substrate stage comprises
 a substantially circular planar base; and 
 a peripheral raised edge to the base, the peripheral raised edge thereby defining a central recessed substrate receiving surface, the central recessed substrate receiving surface being substantially planar, the peripheral raised edge to the base comprising an inner edge and an outer edge, the inner edge comprising a bevel. 
 
     
     
         18 . An apparatus as claimed in  claim 17  wherein the peripheral raised edge comprises an upper surface and a lower surface and the peripheral raised edge comprises an annular groove in at least one or both of the upper and lower surfaces. 
     
     
         19 . An apparatus as claimed in  claim 17  wherein the peripheral reflector comprises a cylindrical body around the substrate stage and the peripheral reflector is spaced laterally from the peripheral raised edge of the substrate stage. 
     
     
         20 . An apparatus as claimed in  claim 12  comprising more than two chambers in the network. 
     
     
         21 . An apparatus as claimed in  claim 14  comprising a vacuum pump in series after a final chamber. 
     
     
         22 . A substrate stage for the manufacture of gem grade diamonds, the substrate stage comprising
 a substantially circular planar base; and   a peripheral raised edge to the base, the peripheral raised edge thereby defining a central recessed substrate receiving surface, the central recessed substrate receiving surface being substantially planar, the peripheral raised edge to the base comprising an inner edge and an outer edge, the inner edge comprising a bevel.   
     
     
         23 . A substrate as claimed in  claim 22  wherein the bevel defines an upper sharp edge and a lower sharp edge, the upper sharp edge and the lower sharp edge together assisting in defining a plasma region in use. 
     
     
         24 . A substrate stage as in  claim 22  wherein the peripheral raised edge to the base comprises an annular groove. 
     
     
         25 . A substrate stage as in  claim 22  wherein the peripheral raised edge to the base comprises an upper surface and a lower surface and the peripheral raised edge comprises an annular groove in at least one of the upper and lower surfaces.