Kaufman & Robinson, Inc.

International Business Machines Corporation

Other

Ion Tech Limited

Front Range Fakel, Inc.

Veeco Instruments Inc.

Advanced Energy Industries, Inc.

Harold R Kaufman

James R Kahn

Raymond S Robinson

Viacheslav V Zhurin

Jerome J Cuomo

James M Harper

David Alan Baldwin

Paul D Reader

Stephen Mark Rossnagel

Steven J Geissler

Todd Lanier Hylton

Richard E Nethery

James L Speidell

Denis M Shaw

Boris Ciorneiu

Mordehai Heiblum

William E Hughes

Rhonda J Parker

Kirk A Thompson

Chris M Shonka

Vadim Konstantinovich Kharchevnikov

Aleksei Ivanovich Morozov

Aleksei Vasilievich Desiatskov

Antonina Ivanovna Bugrova

Antonina I Bugrova

Vadim K Kharchevnikov

Aleksei V Desiatskov

Aleksei I Morozov

In accordance with one embodiment of the present invention, an end-Hall ion source has an electron emitting cathode, an anode, a reflector, an internal pole piece, an external pole piece, a magnetically permeable path, and a magnetic-field generating means located in the permeable path between the two pole pieces. The anode and reflector are enclosed without contact by a thermally conductive cup that has internal passages through which a cooling fluid can flow. The closed end of the cup is located between the reflector and the internal pole piece and the opposite end of the cup is in direct contact with the external pole piece, and wherein the cup is made of a material having a low microhardness, such as copper or aluminum.

End-hall ion source with enhanced radiation cooling

In accordance with one embodiment of the present invention, the dielectric discharge chamber of a generally axially symmetric ion source has a hollow cylindrical shape. One end of the discharge chamber is closed with a dielectric wall. The working gas is introduced through an aperture in the center of this wall. The ion-optics grids are at the other end of the discharge chamber, which is left open. The inductor is a helical coil of copper conductor that surrounds the cylindrical portion of the dielectric discharge chamber. The modification that produces uniformity about the axis of symmetry is a shorted turn of the helical-coil inductor at the end of the inductor closest to the ion-optics grids.

Mitigation of plasma-inductor termination

In accordance with one embodiment of the present invention, there is provided a switch-mode power supply to generate the heating current for a hot-filament electron-emitting cathode. The power supply directly couples, without an output power transformer, the output from a full-bridge converter that operates at an output frequency in the range from ten Hz to tens of Khz to the output terminals of the power supply. A connection to a reference potential that minimizes the potential fluctuation of the cathode is provided by the center tap on an autotransformer connected across the output terminals, where the conductors in the autotransformer are sized for half of the emission current from the cathode rather than the much larger heating current.

Power supply for a hot-filament cathode

In accordance with one embodiment, the hollow cathode is comprised of a first tantalum tube, tantalum foil, and a second tantalum tube. The foil is in the form of a spiral winding around the outside of the first tube and is held in place by the second tube, which surrounds the foil. One end of the second tube is approximately flush with one end of the first tube. The other end of the second tube extends to a cathode support through which the working gas flows. To start the cathode, a flow of ionizable inert gas, usually argon, is initiated through the hollow cathode and out the open end of the first tube. An electrical discharge is then started between an external electrode and the first tube. When the first tube is heated to operating temperature, electrons are emitted from the open end of the first tube.

Industrial hollow cathode

In accordance with one embodiment of the present invention, the hollow-cathode apparatus comprises a small-diameter tantalum tube with a plurality of tantalum-foil radiation shields, wherein the plurality of shields in turn comprise one or more spiral windings external to that tube and approximately flush with the open end from which electron emission takes place. The axial length of at least one of the inner windings (closer to the tantalum tube) is equal to or less than approximately half the length of the tantalum tube. An enclosed keeper surrounds the cathode. To start the cathode, a flow of ionizable inert gas, usually argon, is initiated through the cathode and out the open end. An electrical discharge is then started between the keeper and the hollow cathode. When heated to operating temperature, electrons exit from the open end of the hollow cathode.

Industrial hollow cathode with radiation shield structure

In accordance with one embodiment of the present invention, there is provided a switch-mode power supply to generate the heating current for a hot-filament electron-emitting cathode. The power supply directly couples, without an output transformer, the output from a full-bridge converter that operates at an output frequency in the range from ten Hz to ten kHz. A connection to a reference potential that minimizes the potential fluctuation of the cathode is provided by one of the direct-current inputs to the converter.

In accordance with one specific embodiment of the present invention, a Hall-current ion source is operated in a pulsed mode where the pulse duration is short compared to the time for discharge fluctuations to develop. For a reduced loss of neutral gas, the time between pulses should be less than, or about equal to, the fill time for the ionizable gas in the discharge volume of the Hall-current ion source.

Pulsed operation of hall-current ion sources

In accordance with one specific embodiment of the present invention, the ion optics for use with an ion source have a plurality of electrically conductive grids that are mutually spaced apart and have mutually aligned respective pluralities of apertures through which ions may be accelerated and wherein each grid has an integral peripheral portion. A plurality of moment means are applied to a circumferentially distributed plurality of locations on the peripheral portion of each grid, which is initially flat, thereby establishing an annular segment of a cone as the approximate shape for that peripheral portion and a segment of a sphere as the approximate dished shape for the grid as a whole. The plurality of grids have conformal shapes in that the direction of deformation and the approximate spherical radii are the same. This elastic deformation during installation avoids any need for any permanent or inelastic deformation during fabrication, as well as controlling the excessive thermal displacements and accompanying performance changes to which flat grids are prone.

Ion optics with shallow dished grids

In one embodiment of this invention, the apparatus for sputter deposition within an evacuated volume comprises a compact gridless ion source into which an ionizable gas is introduced and from which ions leave with directed energies at or near the sputtering threshold and a sputter target near that source, biased negative relative to the surrounding vacuum enclosure, and located within the beam of ions leaving that source. Particles sputtered from the target are deposited on a deposition substrate spaced from both the ion source and the sputter target. An energetic beam of electrons can be generated by the incident ions striking the negatively biased sputter target and the deposition substrate is located either within or outside of this beam, depending on whether the net effect of bombardment by energetic electrons is beneficial or detrimental to that particular deposition process.

Apparatus for sputter deposition

In accordance with one specific embodiment of the present invention, a Hall-current ion source of the end-Hall type has an anode that is contoured with one or more recesses in the electron-collecting surface which have areas that are protected from the deposition of externally generated contamination thereon, as well as one or more protrusions that have higher temperatures than the bulk of the anode, thereby increasing the removal or passivation of coatings during operation by the thermal degradation of the coating and the effects of thermomechanical stresses. In another specific embodiment, which can be combined with the above embodiment, electrically isolated baffle or baffles are located to protect a substantial fraction of the electron-collecting surface of the anode from the deposition of externally generated contamination thereon.

Hall-current ion source

In accordance with one embodiment of the present invention, the ion-beam apparatus takes the form of a gridless ion source with a hot-filament cathode-neutralizer, in which the hot filament is heated with a current from the cathode-neutralizer heater. The cathode-neutralizer is connected to the negative terminal of the discharge supply for the gridless ion source. This connection is substantially isolated from ground (the potential of the surrounding vacuum chamber, which is usually at earth ground) and its potential is measured relative to ground. The heater current to the cathode-neutralizer is controlled by adjusting it so as to maintain this potential in a narrow operating range. This control can be manual or automatic.

Ion-source neutralization with a hot-filament cathode-neutralizer

In accordance with one specific embodiment of the present invention, the apparatus for sputter deposition within an evacuated volume comprises a compact ion source to generate ions into which an ionizable gas is introduced and from which ions leave with directed energies near or below the sputtering threshold, a sputter target near that source and located within the beam of ions leaving that source, a sputter target with a grounded shield that defines the target portion exposed to sputtering, and a power supply to bias the target negative relative to ground so that ions are attracted to and sputter the target. Particles sputtered from the target are deposited on a deposition substrate separate from both the ion source and the sputter target. For an insulating target, the target is biased with a radiofrequency power supply and the bias has a mean negative value rather than a direct-current negative value relative to ground. The rate and energy with which the ions arrive at the target determine the rate with which that target is sputtered and the deposition rate on the substrate. In using a compact gridless ion source, the high pressure required for generating ions is confined to the ion source, reducing the pumping gas load. For ion energies at or near the sputtering threshold, the sputtering from extraneous hardware is reduced or eliminated. In addition, the target biases can be low enough to minimize the damage due to energetic neutrals that result from reflection of energetic target ions.

In accordance with one embodiment of the present invention, the ion-beam apparatus takes the form of an end-Hall ion source in which the detachable anode module incorporates the outer pole piece and includes an enclosure around the anode that both minimizes the loss of working gas and confines sputter contamination to the interior of this enclosure. This detachable anode module is substantially smaller than the entire end-Hall ion source, weighs substantially less, and can be duplicated for significantly less cost than the duplication of the entire ion source. In general, the components of the magnetic circuit determine the overall size, weight, and much of the cost of a gridless ion source. The reduced size, weight, and cost of the detachable anode module compared to the entire ion source is due to most of the magnetic circuit being excluded from the detachable module.

Modular gridless ion source

In accordance with an embodiment of the present invention, apparatus for ion-assisted magnetron deposition takes a form that includes a magnetron, a deposition substrate displaced from the magnetron, and an ion source also displaced from the magnetron and located so that the ion beam from the ion source is directed at the deposition substrate. The ion source is operated without an electron-emitting cathode-neutralizer, the electron current for this function being provided by electrons from the magnetron. In one specific embodiment, the ion source is operated so that the potential of the deposition substrate is maintained close to that of a common ground for the magnetron and the ion source. In another embodiment, the ion source is of the Hall-current type and the discharge current of the ion source is approximately equal in magnitude to the current of the magnetron discharge.

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Laporte, CO, United States of America

Harold R Kaufman