Hughes Aircraft Company

Wolfgang Knauer

John L Bartelt

Hayden E Gallagher

Walter E Perkins, Jr

An ion cluster beam can be focused and delivered to a target with a selected energy range by directing the ionized beam through a beam crossover, and furnishing an energy-selecting apertured plate adjacent to the beam crossover so that the center of the beam passes through the aperture. The beam crossover is distributed along the beam axis due to the different energies of the particles in the beam. The apertured plate in the beam path removes from the beam those clusters having energies lower than and/or greater than an acceptable energy range, depending upon its placement and diameter, to provide energy selectivity. The portion of the beam passing through the aperture is imaged upon the target by a lens, and the beam may be deflected by deflector coils to write patterns across the surface of the target.

Production of focused ion cluster beams

Beams of energetic atoms are produced by furnishing a beam of energetic ionized clusters and disintegrating the clusters to produce a beam of energetic atoms. The energetic ionized clusters are provided by forming a beam containing uncharged particles, both clusters and atoms, ionized the particles, accelerating the particles, separating any unionized particles from the beam, and removing those particles outside a selected size range from the beam. The resulting energetic beam of ionized clusters is impacted against a cluster scattering plate so that the clusters break apart into unclustered atoms and ions. The ions are removed from the beam of unclustered atoms, which is available for use as needed. The atoms have energies dependent upon the cluster beam conditioning, but which are typically in the range of 1-10 electron volts per atom.

Production of energetic atom beams

An apparatus for producing a beam of ionized clusters includes a source that emits a beam of clustered and unclustered atoms through a nozzle and a cold cathode ionizer that ionizes the clusters. The ionizer is positioned in close proximity to the nozzle and the beam as it is emitted from the nozzle. A plasma is formed in the beam adjacent the nozzle when secondary electrons emitted from the cathode are accelerated and injected into the beam, resulting in the ionization of atoms and clusters. The cathode is preferably formed, at least in part, of a material that efficiently emits secondary electrons when impacted by ionized atoms extracted from the plasma to impact against the cathode, and the secondary electrons are injected into the plasma to renew the process. The ionized clusters remain in the beam and proceed to their target.

Cluster beam apparatus utilizing cold cathode cluster ionizer

A cluster source includes at least two separate zones, each of whose temperatures can be independently controlled. A crucible contains the species to be evaporated, and is heated to a sufficiently high temperature that efficient evaporation is achieved. A cluster formation surface is adjacent to the crucible and receives evaporated atoms from the crucible. Clusters are produced at the cluster formation surface from the evaporated atoms, and the cluster formation surface is maintained at a temperature lower than that of the crucible to encourage good formation efficiency. Optionally, a third zone can be provided for ejection of the clusters, which is maintained at a higher temperature than the cluster formation surface to prevent formation of droplets of the evaporant.

Cluster source for nonvolatile species, having independent temperature

A source of clusters of atoms is provided, wherein the clusters are thermally conditioned after their formation so that the clusters are in the liquid state. A beam of clusters is first formed during the mixing of a stream of atoms and a carrier gas. The beam of clusters mixed with carrier gas is passed through a conditioner, preferably including a heated drift tube, to bring the clusters to a temperature whereat the clusters are in a condensed state without crystalline order, comparable to the liquid state. The conditioned cluster beam passes to vacuum, with separation and removal of a large portion of the carrier gas mixed therewith, so that cooling of the clusters in the cluster beam is minimized during their flight to the cluster target.

Carrier gas cluster source for thermally conditioned clusters

Chemical reactions are accomplished at a surface of a substrate by supplying both a chemical reactant and energy by means of a cluster beam of a volatile material. Discrete units containing a volatile reactant are formed into clusters, ionized, accelerated to high energy, and impacted against the surface. The clusters disintegrate, and the reactant species reacts at the surface, under the influence of the energy transferred by the accelerated cluster. The clustered species may be the only reactant, as in a decomposition reaction, or additional reactants may be supplied from the surface or from other external sources, as in a film deposition, etching reaction, or catalysis reaction.

Energy intensive surface reactions using a cluster beam

An apparatus for producing a beam of ionized clusters, having a cluster source and an ionizer, includes an electrostatic mass separator which permits only those clusters having a mass greater than a selected value to pass. Unclustered ions and clusters of smaller size are reflected and do not reach the substrate target. The mass separator has a retarding field electrode and an entrance electrode, both in the form of grids with the grid openings aligned. Use of a second electrostatic mass separator allows selection of a narrow range of cluster masses for acceleration against the substrate.

Mass separator for ionized cluster beam

Charged particle source (14) delivers beam (20) which is collimated onto first aperture plate having first aperture (28). The beam passing therethrough is deflected by deflection plates (32, 34, 38 and 40) with respect to second aperture (46) in second aperture plate (44). The image (50) of the second aperture (46) is focused on the target plane (16) and the projected image of the footprint (58) of the deflected beam is focused on the target plane (16). When these images overlap, a shaped beam (56) passes through. Scanning of the beam across the target plane by deflection plates (52 and 54) permits exposure of sharp-edged features (62) by positioning the image (60a) inside the margin (64) and then scanning the image (50b) thereacross to expose the sharp edge and thereupon picking up the image (60) so that they both scan across the feature to be exposed.

Method and apparatus for spot shaping and blanking a focused beam

Electron or ion beam shaping apparatus has first aperture (28) and second aperture (30) through which the beam (20) is focused by first lens (24). Double deflection apparatus of either electromagnetic or electrostatic character is small and can be positioned between the aperture plates so that the image of both apertures can be focused on the target (16). Double deflection serves to vary spot size and shape and assures that target current density does not change while spot size is varied.

Electron and ion beam-shaping apparatus

Beam deflection apparatus 50 has first and second conductors 64 and 68 positioned transversely in the path of beam 67 and has a resistive connector 78 to be tuned to deflection amplifier 52 and transmission line 54 to provide magnetic deflection. Capacitive plates 74 and 76 are charged by the deflection current to provide substantially equal electrostatic deflection in the same direction.

Electron beam blanking apparatus and method

Deflection of an electron beam from axis 28 is controlled by electromagnetic deflection saddle coils 24, 26. Interference with deflection by surrounding mass of lens 22 is overcome by compensation coils 42, 44. The deflection coils and compensation coils are shaped and sized so that their own conductive properties do not distort the deflection magnetic fields. This is accomplished by equalizing between the deflection and compensation coils, the change in magnetic field during coil current penetration and by equalizing the penetration time constants for both sets of windings.

Beam deflection system

Large current is interrupted against high voltage by a high speed mechanical opening line switch connected in series with a saturable reactor. A commutation capacitor is discharged through the closed switch against the line current to produce a current zero. Near the time of current zero the line switch is opened to produce arc free interruption. A dV/dt capacitor is paralleled around the switch to limit the rate of voltage rise. High contact speed of the line switch limits the size of the required dV/dt capacitor to what can be justified economically.

Method and apparatus for interrupting large current

A system control arrangement for power distribution is disclosed in which a line current exceeding a predetermined threshold level is detected as a potential fault current and initiates comparison of the line current and a projected, simulated fault current in a time interval of less than 100 microseconds. The control system responds to a line current exceeding the threshold level to begin a control cycle by opening fast-acting breakers or, inline breakers that switch the current path to a crossed-field switch tube of a current limiting circuit and the control system responds to line current exceeding the simulated fault current over a time period of 1 millisecond to open the current path through the switch tube and thereby insert the current limiting impedance after the millisecond, monitoring time period.

Power distribution control system

Cross-field switch tube has three electrodes to define two concentric annular inter-electrode spaces. A magnet produces a field in both spaces, which field extends out of the switch tube through the electrodes. Circuit connects electrodes so that, with one circuit polarity, the electrode on the outside of one gap is a cathode while, with the other polarity, the electrode on the outside of the other gap is cathode for offswitching a load at any point of the AC cycle.

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Malibu, CA, United States of America

Wolfgang Knauer