Constricted glow discharge plasma source
AssigneeThe Regents of the University of California
InventorANDRE ANDERS
Life of this patent
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Abstract
A miniaturized construction and slit end orifice configurations of a constricted glow discharge chamber and method are disclosed. The polarity and geometry of the constricted glow discharge plasma source is set so that the contamination and energy of the ions discharged from the source are minimized. The several sources can be mounted in parallel and in series to provide a sustained ultra low source of ions in a homogeneous linear plasma stream with contamination below practical detection limits. Other configuration include a hollow chamber with an anode outside the chamber located opposite its discharge constriction orifice. The constriction orifice may be circular or a slit and can be aligned to form a linear array for processing web substrates.
Claims60
A source of plasma comprising:
- a gas supply tube having a gas inlet constriction and an internal gas passage terminating at an open first end, said tube acting as a cathode and being connected to a DC power supply providing a negative voltage to said cathode;
- an electrically non-conductive tube having an internal gas passage connected with said open first end of said gas supply tube with minimal gas leakage therebetween, said non-conductive tube extending beyond said first open end of said tube to a closed end of said tube, an electrically non-conducting end wall having a gas discharge constriction passage therein,
- a metallic covering located on the outside of and substantially in contact with an outside surface of said electrically non-conducting tube and said end wall and having an opening therein corresponding to the location of said gas discharge constriction passage to allow gas flow therethrough, wherein said metallic covering is connected to an electrical ground, where the positive voltage of said DC power supply is connected to said electrical ground;
- and
- a gas source connected to feed gas to said gas supply tube.
A source of plasma comprising:
- a hollow enclosure having a gas inlet opening and an electrically floating end plate having a gas discharge constriction passage therein;
- a cathode surface being exposed to an interior space of said enclosure, wherein said cathode is connected to a DC power supply providing a negative voltage to said cathode;
- an anode surface exposed to gas flow emanating from said discharge constriction passage, wherein said anode is connected to an electrical ground, where the positive voltage of said DC power supply is connected to said electrical ground;
- a gas source connected to feed gas to said gas inlet opening.
A source of plasma comprising:
- a hollow enclosure having a gas inlet opening and an electrically floating end plate having a gas discharge constriction passage therein;
- a cathode surface being exposed to an interior space of said enclosure, wherein said cathode is connected to a DC power supply providing a negative voltage to said cathode;
- an anode surface exposed to gas flow emanating from said discharge constriction passage, wherein said anode is connected to an anode potential near to but different from said electrical ground, where the positive voltage of said DC power supply is connected to said electrical ground;
- a gas source connected to feed gas to said gas inlet opening.
A source of plasma comprising:
- a hollow enclosure having a gas inlet opening and a slot shaped gas discharge constriction passage;
- a cathode surface being exposed to an interior space of said enclosure, wherein said cathode is connected to a DC power supply providing a negative voltage to said cathode;
- an anode surface exposed to said discharge constriction passage, wherein said anode is connected to an electrical ground, where the positive voltage of said DC power supply is connected to said electrical ground;
- a gas source connected to feed gas to said gas inlet opening.
A method for producing a plasma from a plasma source comprising the steps of:
- using a feed tube to supply gas and DC power to an end of said feed tube which is connected to an insulating sleeve connected to the end of said feed tube and extending beyond the end of said feed tube;
- providing an inlet orifice requiring gas to pass through said inlet orifice to flow into said feed tube;
- providing an constriction orifice in an end wall of said insulating sleeve;
- providing a metallic cover over an outside surface of an end of said insulating sleeve at a location beyond and separated from a location of said feed tube;
- connecting a negative voltage of a DC power source to said feed tube;
- connecting said metallic cover to an electrical ground which is connected to a positive voltage of a DC power source;
- energizing said DC power source;
- and
- supplying gas to said feed tube.
A method for producing a plasma comprising the steps of:
- providing gas to a hollow chamber through an inlet orifice of a cathode located at a feed end of the hollow chamber, where side walls of said chamber are made of an electrically insulating material and a discharge end of said chamber is a metal plate having a constriction orifice therein;
- placing an anode at a location outside of said hollow chamber opposite said metal plate;
- and
- connecting said cathode to a negative voltage of a DC power source and connecting a positive voltage of said DC power source to said anode.
Dependencies are inferred from the claim text.