Atmospheric-pressure plasma jet

Patent · Fri Jan 01 00:00:00 EST 1999

OSTI ID:872560

Selwyn, Gary S ^[1]

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1. Los Alamos, NM

Atmospheric-pressure plasma jet. A .gamma.-mode, resonant-cavity plasma discharge that can be operated at atmospheric pressure and near room temperature using 13.56 MHz rf power is described. Unlike plasma torches, the discharge produces a gas-phase effluent no hotter than 250.degree. C. at an applied power of about 300 W, and shows distinct non-thermal characteristics. In the simplest design, two concentric cylindrical electrodes are employed to generate a plasma in the annular region therebetween. A "jet" of long-lived metastable and reactive species that are capable of rapidly cleaning or etching metals and other materials is generated which extends up to 8 in. beyond the open end of the electrodes. Films and coatings may also be removed by these species. Arcing is prevented in the apparatus by using gas mixtures containing He, which limits ionization, by using high flow velocities, and by properly shaping the rf-powered electrode. Because of the atmospheric pressure operation, no ions survive for a sufficiently long distance beyond the active plasma discharge to bombard a workpiece, unlike low-pressure plasma sources and conventional plasma processing methods.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• DOE Contract Number: W-7405-ENG-36
• Assignee: Regents of University of California (Los Alamos, NM)
• Patent Number(s): US 5961772
• OSTI ID: 872560
• Country of Publication: United States
• Language: English

Related Subjects

atmospheric-pressure
plasma
jet
gamma
-mode
resonant-cavity
discharge
operated
atmospheric
pressure
near
temperature
13
56
mhz
rf
power
described
unlike
torches
produces
gas-phase
effluent
hotter
250
degree
applied
300
distinct
non-thermal
characteristics
simplest
design
concentric
cylindrical
electrodes
employed
generate
annular
region
therebetween
long-lived
metastable
reactive
species
capable
rapidly
cleaning
etching
metals
materials
generated
extends
films
coatings
removed
arcing
prevented
apparatus
gas
mixtures
containing
limits
ionization
flow
velocities
properly
shaping
rf-powered
electrode
operation
survive
sufficiently
distance
active
bombard
workpiece
low-pressure
sources
conventional
processing
methods
concentric cylindrical
flow velocities
atmospheric-pressure plasma
processing methods
processing method
pressure plasma
plasma sources
plasma discharge
gas mixtures
plasma source
atmospheric pressure
gas mixture
plasma process
rf power
plasma processing
plasma torch
annular region
reactive species
mixtures containing
plasma jet
thermal characteristics
active species
mhz rf
conventional plasma
cylindrical electrodes
cylindrical electrode
unlike plasma
plasma torches
active plasma
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