Atmospheric-pressure plasma jet

Patent · Thu Dec 31 23:00:00 EST 1998

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
• 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

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/156/118/315/
13
250
300
56
active
active plasma
active species
annular
annular region
apparatus
applied
arcing
atmospheric
atmospheric pressure
atmospheric-pressure
atmospheric-pressure plasma
bombard
capable
characteristics
cleaning
coatings
concentric
concentric cylindrical
containing
conventional
conventional plasma
cylindrical
cylindrical electrode
cylindrical electrodes
degree
described
design
discharge
distance
distinct
effluent
electrode
electrodes
employed
etching
extends
films
flow
flow velocities
gamma
gas
gas mixture
gas mixtures
gas-phase
generate
generated
hotter
ionization
jet
limits
long-lived
low-pressure
materials
metals
metastable
methods
mhz
mhz rf
mixtures
mixtures containing
near
non-thermal
operated
operation
plasma
plasma discharge
plasma jet
plasma process
plasma processing
plasma source
plasma sources
plasma torch
plasma torches
power
pressure
pressure plasma
prevented
processing
processing method
processing methods
produces
properly
rapidly
reactive
reactive species
region
removed
resonant-cavity
rf
rf power
rf-powered
shaping
simplest
sources
species
sufficiently
survive
temperature
therebetween
thermal characteristics
torches
unlike
unlike plasma
velocities
workpiece