Ion source based on the cathodic arc
AssigneeThe United States of America as represented by the United States Department of Energy
InventorsDavid M. Sanders, Steven Falabella
Life of this patent
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Abstract
A cylindrically symmetric arc source to produce a ring of ions which leave the surface of the arc target radially and are reflected by electrostatic fields present in the source to a point of use, such as a part to be coated. An array of electrically isolated rings positioned in the source serves the dual purpose of minimizing bouncing of macroparticles and providing electrical insulation to maximize the electric field gradients within the source. The source also includes a series of baffles which function as a filtering or trapping mechanism for any macroparticles.
Claims22
An ion source utilizing a cathodic arc to produce a highly ionized metal vapor useful in the production of dense, adherent coatings, comprising:
- a vacuum chamber having a dome-shaped section at one end thereof;
- an annular cathode constituting an arc target located within said dome-shaped section of said vacuum chamber;
- an annular anode located within said dome-shaped section of said vacuum chamber and spaced from said cathode;
- a magnetic coil located external of said vacuum chamber and adjacent said dome-shaped section;
- a plurality of insulating rings located within said dome-shaped section of said vacuum chamber intermediate said cathode and a portion of said anode;
- baffle means located within said dome-shaped section of said vacuum chamber;
- and
- means for moving an arc spot on said arc target;
- whereby a ring of ions leave the arc target in a radial direction and are reflected by electrostatic fields within said dome-shaped section of said vacuum chamber toward a point of use, and whereby any macroparticles produced by the arc target move in a radial direction and are trapped by said plurality of insulating rings and said baffle means.
In a cathodic vacuum arc ion source having a cathode and an anode located within a vacuum chamber and a magnetic coil located exterior of said chamber whereby electrostatic fields are produced for directing ions from said source to a point of use, the improvement comprising:
- said cathode having a cylindrical configuration whereby ions and macroparticles produced from an arc track extending around said cathode leave a surface of said cathode in a radially outward direction;
- an array of insulating rings positioned within said chamber and intermediate said cathode and at least a section of said anode;
- and
- baffle means positioned within said chamber and adjacent said array of insulating rings;
- whereby ions leaving said surface of said cathode are bent by electrostatic fields within said vacuum chamber for directing same to a point of use, while macroparticles leaving said surface of said cathode are trapped by said array of insulating rings and said baffle means.
A method for producing ions from a target material for coating a part, comprising the steps of:
- positioning within a vacuum chamber a cylindrical cathode formed of material to be coated on a part;
- positioning within the vacuum chamber an annular anode in spaced relation to the cathode;
- positioning within the vacuum chamber an array of insulating rings located intermediate the cathode and at least a portion of the anode;
- locating a magnetic coil about the exterior of the section of the vacuum chamber containing the cathode, anode, and array of insulating rings;
- providing the interior of the vacuum chamber with an annular baffle assembly positioned adjacent an interior wall thereof and adjacent the array of insulating rings;
- providing electrical power to said coil, said cathode, and said anode so as to produce an arc on the surface of the cathode causing the formation of at least ions and macroparticles;
- and
- providing means for changing the location of an arc track on the cathode;
- whereby ions and macroparticles leaving the surface of the cathode move in a radially outwardly direction, wherein the ions are reflected by electrostatic fields formed within the vacuum chamber toward a point of use, and wherein the macroparticles are essentially all trapped by the array of insulating rings and the baffle assembly so as to minimize passage of macroparticles along with the ions to a point for coating a part with the material of the cathode.
Dependencies are inferred from the claim text.