US5558718A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulsed source ion implantation apparatus and method
Assignee: University of California
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Filing: 1994-04-08
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Granted: 1996-09-24
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Expires: 2014-04-08
Abstract
Abstract A new pulsed plasma-immersion ion-implantation apparatus that implants ions in large irregularly shaped objects to controllable depth without overheating the target, minimizing voltage breakdown, and using a constant electrical bias applied to the target. Instead of pulsing the voltage applied to the target, the plasma source, for example a tungsten filament or a RF antenna, is pulsed. Both electrically conducting and insulating targets can be implanted.
Inventors
- 👤 Ka-Ngo Leung
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:55
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32009; H01J37/32412; C; C23; C23C; C23C14/00; C23C14/22; C23C14/48; C23C8/00; C23C8/06; C23C8/36
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
122 words
A plasma immersion ion implantation apparatus comprising: a) a vacuum chamber; b) a plasma source located within said vacuum chamber; c) means to connect electrical pulsing circuitry to the plasma source, said circuitry comprising, i) a sine-wave oscillator; ii) a pulse generator; iii) an RF generator, with one input connected to the output of the sine-wave oscillator and the other input electrically connected to the output of the pulse generator; iv) an isolation transformer; v) a coaxial cable electrically connecting the output of the RF generator to the isolation transformer; vi) an impedance matching circuit with input electrically connected to the isolation transformer and output electrically connected to the plasma source; and d) means to connect a voltage source to the target.
Claim 2
Dependent Claim
122 words
A plasma immersion ion implantation apparatus comprising: a) a vacuum chamber; b) a plasma source located within said vacuum chamber; c) means to connect electrical pulsing circuitry to the plasma source, said circuitry comprising, i) a sine-wave oscillator; ii) a pulse generator; iii) an RF generator, with one input connected to the output of the sine-wave oscillator and the other input electrically connected to the output of the pulse generator; iv) an isolation transformer; v) a coaxial cable electrically connecting the output of the RF generator to the isolation transformer; vi) an impedance matching circuit with input electrically connected to the isolation transformer and output electrically connected to the plasma source; and d) means to connect a voltage source to the target.
Claim 3
Dependent Claim
13 words
The apparatus of claim 1 wherein the vacuum chamber has electrically conducting walls.
Claim 4
Dependent Claim
16 words
The apparatus of claim 1 further comprising an armature or stand to hold target for implantation.
Claim 5
Dependent Claim
22 words
The apparatus of claim 1 wherein the implantation apparatus includes a supply means for supplying an ionizable gas into the vacuum chamber.
Claim 6
Dependent Claim
29 words
The apparatus of claim 4 wherein the gas is selected from the group consisting of nitrogen, hydrogen, oxygen, neon, argon, diborine, arsine, phosphine, xenon, helium, methane, and carbon dioxide.
Claim 7
Dependent Claim
14 words
The apparatus of claim 1 wherein the plasma source is a radio frequency antenna.
Claim 8
Dependent Claim
37 words
The apparatus of claim 1 wherein the RF generator comprises: a) a preamplifier connected to the outputs of the sine-wave oscillator and the pulse generator; and b) a power amplifier connected to the output of the preamplifier.
Claim 9
Dependent Claim
20 words
The apparatus of claim 1 wherein the sine-wave oscillator and the pulse generator are internal components of the RF generator.
Claim 10
Dependent Claim
15 words
The apparatus of claim 1 wherein the plasma source pulsing circuitry comprises an electronic switch.
Claim 11
Dependent Claim
20 words
The apparatus of claim 9 wherein the electronic switch turns a voltage of 100 V or less on and off.
Claim 12
Dependent Claim
23 words
The apparatus of claim 1 wherein the target voltage source applies an electrical potential to the target relative to the vacuum chamber walls.
Claim 13
Dependent Claim
20 words
The apparatus of claim 1 wherein the target voltage source comprises a power supply between 15 kilovolts and 150 kV.
Claim 14
Dependent Claim
20 words
The apparatus of claim 12 wherein the target voltage source comprises a power supply between 20 kilovolts and 100 kV.
Claim 15
Dependent Claim
16 words
The apparatus of claim 13 wherein the target voltage source comprises a 20 kilovolt power supply.
Claim 16
Dependent Claim
18 words
The apparatus of claim 12 wherein a capacitive circuit is connected in parallel to the target voltage source.
Claim 17
Dependent Claim
13 words
The apparatus of claim 15 wherein the capacitive circuit comprises an RC circuit.
Claim 18
Dependent Claim
19 words
The apparatus of claim 15 wherein the circuit's capacitance is determined by the charge that the target can hold.
Claim 19
Dependent Claim
16 words
The apparatus of claim 1 further comprising means for confining the plasma in the vacuum chamber.
Claim 20
Dependent Claim
22 words
The apparatus of claim 18 wherein the confinement means comprises a plurality of magnets spaced about the periphery of the vacuum chamber.
Claim 21
Dependent Claim
11 words
The apparatus of claim 19 wherein the magnets are permanent magnets.
Claim 22
Dependent Claim
13 words
The apparatus of claim 20 wherein the magnets are in a cusp configuration.
Claim 23
Dependent Claim
29 words
The apparatus of claim 1 further comprising means to connect an electronic switch between the target and the target voltage supply to pulse a target voltage on and off.
Claim 24
Dependent Claim
21 words
The apparatus of claim 20 wherein an electronic switch is connected in series with the target and the target voltage supply.
Claim 25
Dependent Claim
27 words
The apparatus of claim 23 wherein the plasma source pulsing circuit turns the plasma source on immediately before the electronic switch turns the target voltage supply on.
Claim 26
Dependent Claim
36 words
The apparatus of claim 23 wherein the target voltage source is switched on for a time that is shorter than the time required for a voltage between the plasma discharge and the target to break down.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-09-24 | 2000-03-25 | 2000-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-09-24 | 2004-03-25 | 2004-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-09-24 | 2008-03-25 | 2008-09-24 | $7700.00 | Window Closed / Lapsed |