Alex Samarian School of Physics, University of Sydney, NSW 2006,
Australia Slide 2 What is Dusty (Complex) Plasma? Laboratory Dusty
Plasma Why Study Complex (Dusty) Plasma? Worldwide Research
Activities Complex Plasma Laboratory at University of Sydney
Materials Fabrication Slide 3 Complex (dusty) plasma Dusty plasmas
occur naturallyDusty plasmas occur naturally Planetary rings Comets
Interstellar gas Noctilucent clouds (upper atmosphere) Combustion
products (fossil fuel MHD generators, solid fuel rocket
exhausts)Combustion products Dust generated during plasma
processing operations which use reactive gases Electrode and wall
erosion Slide 4 Complex (dusty) plasma Plasma contains nano- or
micro- sized particles In discharge plasma, particles become
negatively charged due to impact of more mobile electronsIn
discharge plasma, particles become negatively charged due to impact
of more mobile electrons Presence of dusts changes plasma
properties Charged particles can form arrays: plasma crystal is an
experimental realisation of strongly coupled plasma Plasma Crystal
Slide 5 Features of Complex Plasma Micro-particles can be
visualized individually Plasma time scales are slowed down (e.g.
the dust plasma frequency is about 10 Hz) - plasma studies in slow
motion Damping is small (neutral gas pressure is typically less
than 1 mbar) - studies of fast processes Micro-particles are easily
manipulated (e.g. by laser light pressure) - manipulation
experiments Slide 6 Laboratory dusty plasma E vivi rf powered
electrode Radius = a Charge = Z d e where Zd ~ f(r,t) >> 1
Sheath Boundary F E, F th F g, F i Ions Slide 7 Laboratory dusty
plasma Experimental chamber and image of test dust particles
levitated above the electrode. The test grains are generated in the
discharge (power up to 200W, pressure up to 1 torr) by electrode
sputtering. Actual View Slide 8 Laboratory dusty plasma =4952 m
=4871 m =1994 m =4064 m =2422 m =4184 m =2893 m =4513 m Planar-2
Planar-6 (1,5) Planar-10 (3,7) Planar-3 Planar-7 (1,6) Planar-11
(3,8) Planar-4 Planar-8 (1,7) =4544 m Planar-9 (2,7) Slide 9 Why
study complex plasmas? Such plasmas are of astrophysical interest
(planetary rings, comets, intergalactic space) Need to control the
dust produced during plasma processingNeed to control the dust
produced during plasma processing Basic physics of interaction of
plasmas with solids New phenomena - particles become charged and
can form plasma crystals which can serve as model systems for the
solid state phenomena New wave modes in dusty plasmas Instabilities
in plasma crystals Opportunities for production of novel materials
in nano- and micro- particle form (non-equilibrium plasma
chemistry) Micro-diagnostic probes Environmental interest -
noctilucent clouds Slide 10 Worldwide research activities Plasma
crystals Charging of dust Instabilities Japan, USA, Germany,
France, UK, Russia, HollandJapan, USA, Germany, France, UK, Russia,
Holland Complex plasma in microgravity condition 1996 - first
parabolic flight (Max Plank Institute, Germany, ESA) 1997 - first
experiment on board of space station Mir (IVTAN, RAS) 1999 - IMF
program (Germany & Russia, later joined by 8 other
countries)IMF program 2001 - PKE-1 experiments started on board of
ISS (ESA, NASA) 2002 - Materials research on PKE installation
(leaded by French team) Control dusts during plasma processing
(IBM, Sony) Dusts near wall region of plasma reactors (France,
ITERA) Complex plasma in the Universe (NASA) Slide 11 Complex
Plasma in Sydney 1.Sergey Vladimirov 2.Brian James 3.Felix Cheung
4.Neil Cramer 5.William Tsang 6.Alex Samarian 2 1 6 3 5 4 Slide 12
Complex Plasma Laboratory Dynamical phenomena Dust Oscillation Dust
Vortices Dust Cluster Rotation Charging of Dust particles Phase
Transition Diffusion Dust as novel diagnostic tool Slide 13 CPL
Publications 2001 Self-excited vertical oscillations in an
rf-discharge dusty plasma Physical Review E, 64, 025402(Rapid
Communication) (2001). Plasma Kinetics around a Dust Grain in an
Ion Flow Physical Review E, Vol. 63, No. 1, Pp. 017401/1-4 (2001)
Sheath measurement in rf-discharge plasma with dust grains Physics
Letters A, 287, 125 (2001) Dynamics of the Charging and Motion of a
Macroparticle in a Plasma Flow Physical Review E, Vol. 63, No. 4,
Pp. 045401( Rapid Communication )/1-3 (2001) Positively charged
particles in dusty plasmas Physical Review E, 64, 056407 (2001)
Theory of Collision-dominated Dust Voids in Plasmas Physical Review
E, Vol. 63, No. 5, Pp. 056609/1-11 (2001) Behaviour of Dust Grain
in the Double Layer of an Electric Probe in a Gas- Discharge Plasma
Physics Reports, 27, 340 (2001) Interaction of a Rodlike Charged
Macroparticle with a Flowing Plasma Physical Review E, Vol. 64, No.
2, Pp. 026403/1-7 (2001) Self-excited motion of Dust Particles in a
Inhomogeneous Plasma Physics Letters A, 289, 240 (2001)
Oscillations in a Chain of Rod-shaped Colloidal Particles in a
Plasma Physical Review E, Vol. 64, No. 3, Pp. 035402(Rapid
Communication)/1-4 (2001) 2002 Rotation of Coulomb clusters in
magnetised dusty plasma Physica Scripta, T98, 143 (2002) Diffusion
and Dynamics of Macro-particles in a Complex Plasma Physics of
Plasmas, Vol. 9, No. 3, Pp. 835-840 (2002) Stability of Particle
Arrangements in a Complex Plasma Physical Review E, Vol. 65, No. 4,
Pp. 046416/1-4 (2002) Criteria of Phase Transitions in a Complex
Plasma Physical Review Letters, Vol. 88, No. 24, Pp. 245002/1-4
(2001) Formation of vertical and horizontal dust vortexes in an
RF-discharge plasma Physica Scripta, T98, 123 (2002) Comment on
"Dependence of the Dust-Particle Charge on Its Size in a Glow-
Discharge Plasma" Physical Review Letters, Vol. 89, No. 22, P.
229501 (2002) Optical diagnostics of plasma and particle in an
atmospheric pressure dusty plasma Physica Scripta, 66, 82 (2002)
Vibrational Modes in Plasma Crystals due to Nonlinear temperature
Distribution in Gas Discharge Plasmas 2003 Rotation of Coulomb
crystals in magnetized inductively coupled complex plasma IEEE
Transaction Plasma Science 31, Issue 1 (2003) The rotation of
planar-2 to planar-12 dust clusters in an axial magnetic field New
Journal of Physics, Focus Issue on Complex Plasma (2003) Slide 14
Materials fabrication Grow particles Nano to microsize Unifom size
Particles can be coated - examples metal coating using auxiliary
magnetron sputtering source a -C:H coating of SiO 2 particles
Alumina coating of fluorescent particles to protect particle
against degradation and aging and to improve adhesion Slide 15
Growth of particles Reactive species are generated by
dissociation/ionisation of gases in discharge (e.g. in fluorocarbon
plasmas used for semiconductor processing) gas phase polymerisation
produces molecules which are precursors for high molecular weight
compounds (~ 100,000 amu) these act as nuclei for few hundred
nanometer size amorphous particles (ex situ TEM) which grow finally
to micrometre-sized particles Using capacitively-coupled reactor
gas phase products studied using FTIR Particle growth monitored by
laser scattering Concentration of gas phase products correlated
with particle production Slide 16 Growth of particles Argon/methane
and argon/acetylene capacitively- coupled rf plasmas. Gas phase
products studied using FTIR; Particle growth monitors by laser
scattering and laser absorption Strong evidence that C 2 H x is
precursor for particle growth Particle growth occurs spontaneously
in argon/acetylene plasma Occurs in argon/methane transiently when
acetylene added Slide 17 Uniform Ion Flow Wake Ion Cone Wafer
Materials Fabrication Slide 18 Please visit our Complex Plasma
Laboratory website at:
http://www.physics.usyd.edu.au/plasma/complex/index.html Slide 19
Dust in plasma processing Particles produced during etching
processes Dust charges and levitates in sheath above silicon wafer
When plasma extinguished, dust falls on wafer Ways devised to
remove suspended dust As feature size decreases, and
inductively-coupled devices become more common, deposition of
nanometre sized particles during processing is new problem
Efficiency of silicon solar cells improved if nanometre-sized dust
particles formed in silane discharge are imbedded in deposited
silicon film Back Slide 20 Nebulae Comet Tails Planet Rings In
nature, in the universe Examples of Complex Plasma Slide 21 Solid
Propellant In our world, in the laboratory Examples of Complex
Plasma Microelectronics MHD Generator European TOR wafer Slide 22
PLASMA CRYSTALS IN SPACEPLASMA CRYSTALS IN SPACE: EXPERIMENTS IN
WEIGHTLESS CONDITIONS IN THE SPACE STATIONS Slide 23 Charge
Mechanism for Dust Back Slide 24 Dusty Plasma Experiments
