Cold cathode ion beam deposition apparatus with segregated gas flow

Abstract

A cold cathode closed drift ion source is provided with segregated gas flow. A first gas may be caused to flow through or along a path around a peripheral portion of an anode so as to pass through the electric gap between the anode and cathode. A second gas (different from the first gas) may be caused to flow toward the ion emitting slit, without much of the second gas having to pass through the electric gap(s). If it is desired to utilize a gas which produces insulative material (e.g., an organosilicon gas), this gas may be used as the second gas. Accordingly, insulative material buildup in the electric gap between the anode and cathode may be reduced, and changes in beam chemistry can be achieved without unduly altering ion beam characteristics.

What is claimed is:  
     
       1. An ion beam source with a closed loop ion emitting slit capable of emitting an ion beam toward a substrate, the ion beam source comprising: 
       a hollow cathode;  
       an anode located at least partially in a portion of said hollow cathode and spaced from said cathode in a manner so as to form an electrical gap between said anode and said cathode through which electrons flow, said anode including an inner periphery and an outer periphery;  
       at least one magnet for generating a magnetic field proximate a closed loop slit formed in said cathode, wherein an ion beam is emitted toward a   the substrate from an area in or proximate said slit;  
       a first gas flow aperture or channel located adjacent a periphery of said anode for enabling a first gas to flow around the periphery of the anode and through said electrical gap toward said slit; and  
       at least one second gas flow channel or aperture located within a body of said anode between said inner and outer peripheries of said anode, said at least one second gas flow channel or aperture for enabling a second gas to flow through said second gas flow channel or aperture toward said slit such that at least a portion of the second gas flowing through said second gas flow channel or aperture reaches said closed loop slit without having to pass through said electrical gap between said anode and said cathode.  
     
     
       2. The ion beam source of  claim 1 , wherein said second gas flow channel or aperture comprises a continuous aperture which surrounds said magnet that is encompassed by said inner periphery of said anode. 
     
     
       3. The ion beam source of  claim 1 , further comprising a plurality of spaced apart ones of said second gas flow channels or apertures located within the body of said anode for enabling the second gas to flow through said plurality of second gas flow channels or apertures toward said slit, wherein said plurality of spaced apart ones of said second gas flow channels or apertures are located within said anode such that at least a portion of the second gas flowing through said plurality of spaced apart ones of said second gas flow channels or apertures reaches said slit without having to pass through said electrical gap between said anode and said cathode. 
     
     
       4. The ion beam source of  claim 1 , wherein said first gas comprises an inert gas and said second gas comprises a depositing gas which produces an insulative material. 
     
     
       5. The ion beam source of  claim 4 , wherein said insulative material produced by said second gas includes silicon (Si). 
     
     
       6. The ion beam source of  claim 1 , wherein each of said slit, said first gas flow aperture or channel, and said second gas flow aperture or channel is closed-loop in shape. 
     
     
       7. The ion beam source of  claim 6 , wherein each of said slit, said first gas flow aperture or channel, and said second gas flow aperture or channel is closed-loop in shape and surrounds said magnet when viewed from above. 
     
     
       8. The ion beam source of  claim 1 , wherein said cathode is a cold cathode. 
     
     
       9. The ion beam source of  claim 1 , wherein said cathode comprises a bottom wall and a top wall; and 
       wherein another gas source is provided for directing a depositing gas toward a magnetic field (MF) proximate said slit via at least one gas flow aperture or channel located at a position such that said top wall of said cathode is at least partially located between said at least one gas flow aperture or channel and a portion of said anode, so that the first gas and said depositing gas from said another source are directed toward the magnetic field (MF) proximate said slit from opposite sides of said top wall of said cathode.  
     
     
       10. The ion beam source of  claim 1 , wherein said anode is maintained at an electrical charge that is positive relative to an electrical charge at which said cathode is maintained. 
     
     
       11. An ion beam source capable of emitting an ion beam toward a substrate, the ion beam source comprising: 
       a cathode;  
       an anode located at least partially between respective portions of said cathode, said anode including an inner periphery and an outer periphery;  
       an electrical gap defined between said anode and said cathode;  
       at least one magnet for generating a magnetic field proximate an ion emitting aperture defined in said cathode, wherein an ion beam is emitted toward a  the substrate from an area in or proximate said ion emitting aperture;  
       at least one first gas flow aperture or channel for enabling a first gas to flow around a periphery of the anode and through said electrical gap toward said ion emitting aperture; and  
       at least one second gas flow channel or aperture located within a body of said anode between inner and outer peripheries of said anode, said second gas flow channel or aperture for enabling a second gas to flow through said second gas flow channel or aperture toward said ion emitting aperture.  
     
     
       12. The ion beam source of  claim 11 , wherein said second gas flow channel or aperture is located at a position within said mode such that much of the second gas flowing through said second gas flow channel or aperture reaches said slit without having to pass through said electrical gap between said anode and said cathode. 
     
     
       13. A method of emitting an ion beam toward a substrate, the method comprising the steps of: 
       providing an ion beam source including an anode and a cathode, so that an electrical gap is provided between the anode and cathode;  
       causing a first gas to flow through a first flow area around a periphery of the anode and through the electrical gap toward an aperture defined in the cathode;  
       causing a second gas to flow through a second gas flow channel or aperture defined in a body of the anode and toward the aperture in the cathode; and  
       ionizing at least a portion of at least one of the first and second gases proximate the aperture in the cathode and causing an ion beam to be directed from the aperture in the cathode toward the substrate.  
     
     
       14. The method of  claim 13 , wherein the second gas flow channel or aperture is located in the anode between an inner periphery of the anode and an outer periphery of the anode. 
     
     
       15. The method of  claim 13 , further comprising the steps of: 
       causing an inert gas toflow through the first flow area around a periphery of the anode and through the electrical gap toward the aperture defined in the cathode;  
       causing a depositing gas, including more insulative element material than the first gas, to flow through the second gas flow channel or aperture defined in the body of the anode and toward the aperture in the cathode; and  
       ionizing at least a portion of the depositing gas proximate the aperture in the cathode and causing an ion beam to be directed from the aperture in the cathode toward the substrate.  
     
     
       16. An ion beam source capable of emitting an ion beam toward a substrate, the ion beam source comprising: 
       an anode and a cathode, with an electrical gap defined between said anode and said cathode;  
       at least one first gas flow aperture or channel for enabling a first gas to flow through said electrical gap toward an aperture in said cathode; and  
       at least one second gas flow channel or aperture for enabling a second gas to flow through said second gas flow channel or aperture toward said aperture in said cathode without much of the second gas having to flow through said electrical gap.  
     
     
       17. An ion beam source capable of emitting an ion beam toward a substrate, the ion beam source comprising: 
       
         a cathode;  
       
       
         an anode located proximate an aperture defined in the cathode;  
       
       
         at least one magnet for generating a magnetic field proximate the aperture defined in the cathode, wherein an ion beam is emitted toward the substrate from an area in or proximate the aperture defined in the cathode;  
       
       
         a first gas flow aperture or channel for enabling a maintenance gas to flow by the anode and thereafter into the magnetic field proximate the aperture defined in the cathode so that ions resulting from the maintenance gas flow through the aperture defined in the cathode before reaching the substrate; and  
       
       
         a second gas flow aperture or channel for enabling a depositing gas, different from the maintenance gas, to flow through the second gas flow aperture or channel and approach the aperture defined in the cathode from a side thereof opposite the first gas flow aperture or channel, so that the maintenance gas and the depositing gas approach the aperture defined in the cathode from opposite sides of the cathode. 
       
     
     
       18. The ion beam source of  claim 17 , wherein ions resulting from the depositing gas proceed toward the substrate without passing through the aperture defined in the cathode. 
     
     
       19. The ion beam source of  claim 17 , wherein the depositing gas approaches the aperture defined in the cathode from above the cathode, and the maintenance gas approaches the aperture defined in the cathode from below the cathode. 
     
     
       20. A method of ion beam depositing a layer on a substrate, the method comprising: 
       
         providing an ion source including a cathode, an anode located proximate an aperture defined in the cathode, and at least one magnet for generating a magnetic field proximate the aperture defined in the cathode, wherein an ion beam is emitted toward the substrate from an area in or proximate the aperture defined in the cathode;  
       
       
         causing a maintenance gas to flow by the anode and thereafter into the magnetic field proximate the aperture defined in the cathode so that ions resulting from the maintenance gas flow through the aperture defined in the cathode before reaching the substrate in the ion beam; and  
       
       
         causing a depositing gas, different from the maintenance gas, to approach the aperture defined in the cathode from an opposite side thereof, so that the maintenance gas and the depositing gas approach the aperture defined in the cathode from opposite sides of the cathode. 
       
     
     
       21. A method of ion beam depositing a layer on a substrate, the method comprising: 
       
         providing an ion source including a first electrode, a second electrode located proximate an aperture defined in the first electrode, and at least one magnet for generating a magnetic field proximate the aperture defined in the first electrode, wherein an ion beam is emitted toward the substrate from an area in or proximate the aperture defined in the first electrode;  
       
       
         causing a maintenance gas to flow by the second electrode and thereafter into the magnetic field proximate the aperture defined in the first electrode so that ions resulting from the maintenance gas flow through the aperture defined in the first electrode before reaching the substrate in the ion beam; and  
       
       
         causing a depositing gas, different from the maintenance gas, to approach the aperture defined in the first electrode from an opposite side thereof, so that the maintenance gas and the depositing gas approach the aperture defined in the first electrode from opposite sides thereof.