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M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
FORMATION OF DUST PARTICLESFORMATION OF DUST PARTICLES
AND RELATED PHENOMENAAND RELATED PHENOMENA
Maxime Mikikian
M. Cavarroc, L. Couëdel, Y. Tessier, L. Boufendi
GREMI, Groupe de Recherches sur l'Énergétique des Milieux IonisésOrléans - France
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
FORMATION OF DUST PARTICLES IN A PLASMAFORMATION OF DUST PARTICLES IN A PLASMAWhy ?Why ?Where ?Where ?
EVIDENCE AND DIAGNOSTICS OF DUST PARTICLE FORMATIONEVIDENCE AND DIAGNOSTICS OF DUST PARTICLE FORMATIONElectrical and optical measurementsElectrical and optical measurementsInstabilities induced by dust particle growthInstabilities induced by dust particle growthDesign of singleDesign of single--crystal silicon crystal silicon nanoparticlesnanoparticlesSuccessive generations of dust particlesSuccessive generations of dust particles
SUCCESSIVE GENERATIONS OF DUST PARTICLESSUCCESSIVE GENERATIONS OF DUST PARTICLESDustDust--free region: the voidfree region: the voidSuccessive generations from the voidSuccessive generations from the voidSuccessive generation instabilitiesSuccessive generation instabilitiesVoid instabilities ?Void instabilities ?
CONCLUSIONSCONCLUSIONS
OUTLINEOUTLINE
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
FORMATION OF DUST PARTICLES IN A PLASMAFORMATION OF DUST PARTICLES IN A PLASMAWhy ?Why ?Where ?Where ?
EVIDENCE AND DIAGNOSTICS OF DUST PARTICLE FORMATIONEVIDENCE AND DIAGNOSTICS OF DUST PARTICLE FORMATIONElectrical and optical measurementsElectrical and optical measurementsInstabilities induced by dust particle growthInstabilities induced by dust particle growthDesign of singleDesign of single--crystal silicon crystal silicon nanoparticlesnanoparticlesSuccessive generations of dust particlesSuccessive generations of dust particles
SUCCESSIVE GENERATIONS OF DUST PARTICLESSUCCESSIVE GENERATIONS OF DUST PARTICLESDustDust--free region: the voidfree region: the voidSuccessive generations from the voidSuccessive generations from the voidSuccessive generation instabilitiesSuccessive generation instabilitiesVoid instabilities ?Void instabilities ?
CONCLUSIONSCONCLUSIONS
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
FORMATION OF DUST PARTICLES : WHY ?FORMATION OF DUST PARTICLES : WHY ?
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
FORMATION OF DUST PARTICLES : WHY ?FORMATION OF DUST PARTICLES : WHY ?
Presence of reactive gasesSilane
(SiH4
), Methane (CH4
), Acetylene (C2
H2
)
Material erosionTungsten, Graphite, …
New charged species in the plasma
modifications of plasma properties
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
FORMATION OF DUST PARTICLESFORMATION OF DUST PARTICLES
Reactive gases: SiH4
(microelectronics)
Reactive gases: Hydrocarbon CH4
, C2
H2
(astrophysics, C, CN nanoparticle, DLC)
Sputtering: (industry, fusion)
R.M. Roth et al. Appl. Phys. Lett. (1985)Y. Watanabe et al. Appl. Phys. Lett. (1988)A. Bouchoule
et al. J. Appl. Phys. (1991), Pure Appl. Chem. (1996)
A. Howling et al. Appl. Phys. Lett. (1991)
C. Deschenaux
et al. J. Phys. D: Appl. Phys. (1999)S. Hong et al. Plasma Sources Sci. Technol. (2003)J. Pereira et al. J. Appl. Phys. (2008)I. Stefanovic
et al. New J. Phys. (2003)
K. De Bleecker
et al. Phys. Rev. E (2006)E. Kovacevic
et al. J. Appl. Phys. (2009)
G.S. Selwyn et al. J. Vac. Sci. Technol. A (1989), SiliconG.M. Jellum
et al. J. Appl. Phys. (1990), Aluminium
B. Ganguly
et al. J. Vac. Sci. Technol. A (1993)G. Praburam
et al. J. Vac. Sci. Technol. A (1994)
M. Mikikian
et al. New J. Phys. (2003)C. Arnas
et al. J. Appl. Phys. (2009)
Some references, really NOT EXHAUSTIVE list…
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
A. Bouchoule
et al. Plasma Sources Sci. Technol. (1993)from R.L. Merlino
et al. Phys. Today (2004)
GLOBAL SCHEME OF DUST PARTICLE FORMATION GLOBAL SCHEME OF DUST PARTICLE FORMATION M. Cavarroc
PhD Thesis Univ. Orléans
(2007)
see also A. Bouchoule
et al. Pure Appl. Chem. (1996)
Aggregation is still an open debate due to the
dust particle chargesee for ex. L. Ravi
et al. Phys. Rev. E (2009)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
FORCES : SHAPE OF THE DUST CLOUDFORCES : SHAPE OF THE DUST CLOUDGravity, Electric
force, Ion drag, Neutral
drag, Thermophoresis, Interactions
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
In natureIn astrophysics
•
Planetary rings, atmospheres (CH4
)•
Interstellar clouds (dark nebulae)
WHERE CAN WE FIND DUSTY PLASMAS ?WHERE CAN WE FIND DUSTY PLASMAS ?
Titan
for ex. C. Szopa
et al. Planet. Space Sci. (2006)
for ex. E. Kovacevic
et al. ApJ
(2005)
Horsehead
Nebula
See Talk of Ella Sciamma
O'Brien at 12:10
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
In industry
Dust particles harmful(End of 80s –
beginning of 90s)
Surface processing in microelectronics
(cleanliness is a major requirement)
• Thin film deposition•
Etching
G. Selwyn et al. J. Vac. Sci. Technol. A (1989)R.M. Roth et al. Appl. Phys. Lett. (1985)
Use of reactive gases
SputteringDust particle formation
Dust particle clouds
WHERE CAN WE FIND DUSTY PLASMAS ?WHERE CAN WE FIND DUSTY PLASMAS ?
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
In industry
Dust particles useful(End of 90s)
Dust particle formation (silicon, carbon)
G. Viera
et al. J. Appl. Phys. (2002)
WHERE CAN WE FIND DUSTY PLASMAS ?WHERE CAN WE FIND DUSTY PLASMAS ?
Design of new materialsNanotechnologies
•
Nanostructured
materials• Solar cells (polymorphous silicon)
P. Roca
i Cabarrocas
J. Vac. Sci. Technol. A (1996) • Single electron devices (transistor, memories)
Transistor using silicon nanocrystalsA. Dutta
et al. Jpn. J. Appl. Phys. (2000)
Silicon nanocrystals incorporated in an
amorphous film
CHALLENGEControl the formation and
deposition of grown nanoparticles(size, structure, number, position)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
In fusion devicesDust particles harmful
Wall erosionImpurities in the plasma
Radio-toxicity of dust particles
Tore Supra Tokamak
WHERE CAN WE FIND DUSTY PLASMAS ?WHERE CAN WE FIND DUSTY PLASMAS ?
J. Winter, Plasma Phys. Control. Fusion (2004)C. Arnas
et al. J. Nucl. Mater (2009)S.I. Krasheninnikov
et al. Plasma Phys. Control. Fusion (2008)D.L. Rudakov
et al. Rev. Sci. Instrum. (2008)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
FORMATION OF DUST PARTICLES IN A PLASMAFORMATION OF DUST PARTICLES IN A PLASMAWhy ?Why ?Where ?Where ?
EVIDENCE AND DIAGNOSTICS OF DUST PARTICLE FORMATIONEVIDENCE AND DIAGNOSTICS OF DUST PARTICLE FORMATIONElectrical and optical measurementsElectrical and optical measurementsInstabilities induced by dust particle growthInstabilities induced by dust particle growthDesign of singleDesign of single--crystal silicon crystal silicon nanoparticlesnanoparticlesSuccessive generations of dust particlesSuccessive generations of dust particles
SUCCESSIVE GENERATIONS OF DUST PARTICLESSUCCESSIVE GENERATIONS OF DUST PARTICLESDustDust--free region: the voidfree region: the voidSuccessive generations from the voidSuccessive generations from the voidSuccessive generation instabilitiesSuccessive generation instabilitiesVoid instabilities ?Void instabilities ?
CONCLUSIONSCONCLUSIONS
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
HOW CAN WE DETECT (EASILY) DUST PARTICLESHOW CAN WE DETECT (EASILY) DUST PARTICLESIN A PLASMA ?IN A PLASMA ?
If dust particle density is high
Important loss of free electrons
Plasma properties are highly affected
Ii
Ie
--- -
--
-
Dust particles collect plasma free electrons and acquire a negative charge (floating potential)
New charged species
Clearly
visible on electrical
and
optical
characteristics
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
0 200 400 600 800 1000 12001
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
In a sputtering discharge
Time
5'
10'
15' 20'
M. Mikikian, L. Boufendi, A. Bouchoule, H.M. Thomas, G.E. Morfill, A.P. Nefedov, V.E. Fortov
and the PKE-Nefedov
team, New J. Phys. 5, 19 (2003)
ELECTRICAL MEASUREMENTSELECTRICAL MEASUREMENTSCharging process of dust particles is "universal", whatever the chemistry
All types of electrical measurements could be able to detect dust particles
Example of the discharge current (see also L. Boufendi
et al. Appl. Phys. Lett. (2001))
In a silane
based discharge
Decrease induced by the growth of dust particles
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
Formation of various molecules
N2
, OH, CN, CH, C2
C2
is the indicator of dust particle growth
Swan system 516.52 nm
P = 0.4 mbar Dust
P = 0.8 mbar Dust
P = 1.2 mbar Dust
P = 1.6 mbar Dust0 100 200 300 400 500 600
0
400
800
1200
1600
2000
Time (s)
Inte
nsit
y (a
.u.)
P = 0.4 mbar
P = 0.8 mbar
P = 1.2 mbar
P = 1.6 mbar
C2 consumption for dust particle formation
OPTICAL MEASUREMENTSOPTICAL MEASUREMENTS
M. Mikikian, L. Boufendi, A. Bouchoule, 30th
EPS, ECA Vol. 27A, p. O-3.1B (2003)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
When the global charge of the dust particle
cloud is high
Enhancement of the free electron energy
Enhancement of the argon lines
0 1000 2000 3000 4000 5000 60000
0.5
1
1.5
2
2.5
3
Time (s)
Inte
nsit
y (a
.u.)
750.3 763.5 800.6 763.5 / 800.6
10’ 5’ 2’
OPTICAL MEASUREMENTSOPTICAL MEASUREMENTS
M. Mikikian, L. Boufendi, A. Bouchoule, 30th
EPS, ECA Vol. 27A, p. O-3.1B (2003)
A. Bouchoule
et al.Plasma Sources Sci. Technol. (1994)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
When the global charge of the dust particle
cloud is high
Enhancement of the free electron energy
Enhancement of the argon lines
OPTICAL MEASUREMENTSOPTICAL MEASUREMENTS
M. Mikikian, L. Boufendi, A. Bouchoule, 30th
EPS, ECA Vol. 27A, p. O-3.1B (2003)
A. Bouchoule
et al. Plasma Sources Sci.
Technol. (1994)
A. Bouchoule
et al.Plasma Sources Sci. Technol. (1994)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
ELECTRICAL MEASUREMENTSELECTRICAL MEASUREMENTS
M. Mikikian, M. Cavarroc, L. Couëdel, L. Boufendi, Phys. Plasmas 13, 092103 (2006)
If dust particle density is high Plasma equilibrium is affectedINSTABILITIES
Aggregation
Growth by surface deposition
Time (s)
Amplitud
e of
3H (a.
u.)
M. Cavarroc, M.C. Jouanny, K. Radouane, M. Mikikian, L. Boufendi, J. Appl. Phys 99, 064301 (2006)M. Cavarroc, M. Mikikian, G. Perrier, L. Boufendi, Appl. Phys. Lett. 89, 013107 (2006)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
ELECTRICAL MEASUREMENTSELECTRICAL MEASUREMENTS
1.4 1.5 1.6 1.7 1.830
40
50
60
70
80
90
100
110
120
130
Pressure (mbar)A
ppea
ranc
e tim
e (s
)
Appearance time function of pressure, power
High pressure and/or high power = Fast kinetics
M. Mikikian, M. Cavarroc, L. Couëdel, L. Boufendi, Phys. Plasmas 13, 092103 (2006)
0 100 200 300 400 500 600 700 800
0.5
0.55
0.6
0.65
0.7
0.75
0.8
Time (s)
Am
plitu
de (a
.u.)
Beginning of instabilities
Electron attachment on dust particles
Instability beginning
Plasma on
If dust particle density is high Plasma equilibrium is affectedINSTABILITIES
M. Cavarroc, M.C. Jouanny, K. Radouane, M. Mikikian, L. Boufendi, J. Appl. Phys 99, 064301 (2006)M. Cavarroc, M. Mikikian, G. Perrier, L. Boufendi, Appl. Phys. Lett. 89, 013107 (2006)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
Appearance:
a few hundreds of ms after plasma ignition
Frequency: from 1 to 3 kHz
Duration: a few ms
DUST PARTICLE GROWTH INSTABILITIES: DUST PARTICLE GROWTH INSTABILITIES: ArAr/SiH/SiH44
M. Cavarroc, M. Mikikian, G. Perrier, L. Boufendi, Appl. Phys. Lett. 89, 013107 (2006)
Aggregation
Growth by surface deposition
Nanocrystalaccumulation
Instability
Time (s)
Amplitud
e of
3H (a.
u.) zoom
spectrogram
M. Cavarroc, M.C. Jouanny, K. Radouane, M. Mikikian, L. Boufendi, J. Appl. Phys 99, 064301 (2006)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
Appearance:
a few hundreds of ms after plasma ignition
Frequency: from 1 to 3 kHz
Duration: a few ms
DUST PARTICLE GROWTH INSTABILITIES: DUST PARTICLE GROWTH INSTABILITIES: ArAr/SiH/SiH44
M. Cavarroc, M. Mikikian, G. Perrier, L. Boufendi, Appl. Phys. Lett. 89, 013107 (2006)
Aggregation
Growth by surface deposition
Nanocrystalaccumulation
Instability
Time (s)
Amplitud
e of
3H (a.
u.) zoom
spectrogram
V dc
(Vol
ts)
V dc
(Vol
ts)
M. Cavarroc, M.C. Jouanny, K. Radouane, M. Mikikian, L. Boufendi, J. Appl. Phys 99, 064301 (2006)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
Before instability During instability After instability
Nanocrystals Nanocrystals & dust particles
Dust particles
In Ar/SiH4
this instability is induced by nanocrystal
agglomeration(fast change of the global charge carried by the dust cloud)
~ Attachment induced ionization instability observed in electronegative gases(see W.L. Nighan
et al. Phys. Rev. A (1974), A. Descoeudres
et al. Plasma Sources Sci. Technol. (2003))
M. Cavarroc, M. Mikikian, G. Perrier, L. Boufendi, Appl. Phys. Lett. 89, 013107 (2006)
SINGLESINGLE--CRYSTAL SILICON NANOPARTICLESCRYSTAL SILICON NANOPARTICLES
Instability = Beginning of the agglomeration phase
Instability = Tool to monitor synthesis of nanocrystals
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
DUST PARTICLE GROWTH INSTABILITIES:DUST PARTICLE GROWTH INSTABILITIES:SPUTTERINGSPUTTERING
Measurement of the amplitude of current fundamental harmonics
0 100 200 300 400 500 600 700 800
0.5
0.55
0.6
0.65
0.7
0.75
0.8
Time (s)
Am
plitu
de (a
.u.)
Instability beginning
DC measurements
M. Mikikian, M. Cavarroc, L. Couëdel, L. Boufendi, Phys. Plasmas 13, 092103 (2006)
see
also
G. Praburam
et al. Phys. Plasmas (1996)D. Samsonov et al. Phys. Rev. E (1999)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
DUST PARTICLE GROWTH INSTABILITIES:DUST PARTICLE GROWTH INSTABILITIES:SPUTTERINGSPUTTERING
Measurement of the amplitude of current fundamental harmonics
0 100 200 300 400 500 600 700-0.02
-0.01
0
0.01
0.02
0.03
0.04
Time (s)
Am
plitu
de (a
.u.)
AC measurements
Instability beginningWell-defined
succession of
phases
P1…P3 Chaos RegularHF Chaos
M. Mikikian, M. Cavarroc, L. Couëdel, L. Boufendi, Phys. Plasmas 13, 092103 (2006)
see
also
G. Praburam
et al. Phys. Plasmas (1996)D. Samsonov et al. Phys. Rev. E (1999)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
DUST PARTICLE GROWTH INSTABILITIES:DUST PARTICLE GROWTH INSTABILITIES:SPUTTERINGSPUTTERING
Measurement of the amplitude of current fundamental harmonics
0 100 200 300 400 500 600 700-0.02
-0.01
0
0.01
0.02
0.03
0.04
Time (s)
Am
plitu
de (a
.u.)
AC measurements
Instability beginningWell-defined
succession of
phases
P1 P2 P3 P4
M. Mikikian, M. Cavarroc, L. Couëdel, L. Boufendi, Phys. Plasmas 13, 092103 (2006)
see
also
G. Praburam
et al. Phys. Plasmas (1996)D. Samsonov et al. Phys. Rev. E (1999)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
OPTICAL MEASUREMENTSOPTICAL MEASUREMENTS
M. Mikikian, L. Couëdel, M. Cavarroc, Y. Tessier, L. Boufendi, IEEE Trans. Plasma Sci. 36, 1012 (2008)M. Mikikian, M. Cavarroc, L. Couëdel, L. Boufendi, Phys. Plasmas 13, 092103 (2006)
As for electrical measurements:Changes in the global plasma emission
(increase)
If dust particle density is highPlasma equilibrium is affected
INSTABILITIES
5'' 1' 2' 7' 15' 16'
A change in electrical or optical measurements can be the indication of the presence of dust particles
and attract experimenter attention
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
3H (a.
u)
Time (s)
2nd
dust particlegeneration
3rd
dust particlegeneration
Aggregation Growth by surface deposition
Nanocrystalaccumulation
Instability
M. Cavarroc, M. Mikikian, Y. Tessier, L. Boufendi, Phys. Rev. Lett. 100, 045001 (2008)
SUCCESSIVE GENERATIONSSUCCESSIVE GENERATIONSIN A SILANEIN A SILANE--BASED DISCHARGEBASED DISCHARGE
Cyclic formation of dust particles as long as the discharge is fed with precursors
Easily observed on electrical measurements
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
FORMATION OF DUST PARTICLES IN A PLASMAFORMATION OF DUST PARTICLES IN A PLASMAWhy ?Why ?Where ?Where ?
EVIDENCE AND DIAGNOSTICS OF DUST PARTICLE FORMATIONEVIDENCE AND DIAGNOSTICS OF DUST PARTICLE FORMATIONElectrical and optical measurementsElectrical and optical measurementsInstabilities induced by dust particle growthInstabilities induced by dust particle growthDesign of singleDesign of single--crystal silicon crystal silicon nanoparticlesnanoparticlesSuccessive generations of dust particlesSuccessive generations of dust particles
SUCCESSIVE GENERATIONS OF DUST PARTICLESSUCCESSIVE GENERATIONS OF DUST PARTICLESDustDust--free region: the voidfree region: the voidSuccessive generations from the voidSuccessive generations from the voidSuccessive generation instabilitiesSuccessive generation instabilitiesVoid instabilities ?Void instabilities ?
CONCLUSIONSCONCLUSIONS
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
DUSTDUST--FREE SPACES: THE VOIDFREE SPACES: THE VOIDIn typical cc-rf
discharges a dust-free space appears close to the
plasma center
This void is induced by an ion drag force that pushes away negatively charged dust particles (J. Goree
et al. Phys. Rev. E (1999))
M. Mikikian, L. Couëdel, M. Cavarroc, Y. Tessier, L. Boufendi, New J. Phys. 9, 268 (2007)
The void appears when dust particles reach a sufficiently large size (charge)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
SUCCESSIVE GENERATIONSSUCCESSIVE GENERATIONSIN A SPUTTERING DISCHARGEIN A SPUTTERING DISCHARGE
M. Mikikian, L. Boufendi, A. Bouchoule, H.M. Thomas, G.E. Morfill, A.P. Nefedov, V.E. Fortov
and the PKE-Nefedov
team, New J. Phys. 5, 19 (2003)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
SUCCESSIVE GENERATIONSSUCCESSIVE GENERATIONSIN A SPUTTERING DISCHARGEIN A SPUTTERING DISCHARGE
M. Mikikian, L. Boufendi, A. Bouchoule, H.M. Thomas, G.E. Morfill, A.P. Nefedov, V.E. Fortov
and the PKE-Nefedov
team, New J. Phys. 5, 19 (2003)
see also L. Ravi
et al. Phys. Rev. E (2009)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
Time (s)
Amplitud
e (a
.u.)
M. Cavarroc, M. Mikikian, Y. Tessier, L. Boufendi, Phys. Rev. Lett. 100, 045001 (2008)
Correlation between electrical measurements, OES and LLS
Use of information from PKE-Nefedov
3H ~ free e-
Low density of "big" dust particles
High density of "small" dust particles
Global charge ~ similar
+
SUCCESSIVE GENERATIONSSUCCESSIVE GENERATIONSIN A SILANEIN A SILANE--BASED DISCHARGEBASED DISCHARGE
see also E.V. Johnson et al. Plasma Sources Sci. Technol. (2008)J.-C. Schauer
et al. Plasma Sources Sci. Technol. (2004)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
Time (s)
Amplitud
e (a
.u.)
M. Cavarroc, M. Mikikian, Y. Tessier, L. Boufendi, Phys. Rev. Lett. 100, 045001 (2008)
Correlation between electrical measurements, OES and LLS
Use of information from PKE-Nefedov
LLS ↑
: Dust particles grow in the void
LLS ↓
: Dust particles pushed away from plasma center
Sufficiently big to be detected
+
SUCCESSIVE GENERATIONSSUCCESSIVE GENERATIONSIN A SILANEIN A SILANE--BASED DISCHARGEBASED DISCHARGE
see also E.V. Johnson et al. Plasma Sources Sci. Technol. (2008)J.-C. Schauer
et al. Plasma Sources Sci. Technol. (2004)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
Time (s)
Amplitud
e (a
.u.)
M. Cavarroc, M. Mikikian, Y. Tessier, L. Boufendi, Phys. Rev. Lett. 100, 045001 (2008)
Correlation between electrical measurements, OES and LLS
Use of information from PKE-Nefedov
I750.38
↑
: void opening
Dust particles are pushed away from plasma center continuing their
growth
I750.38
↓
: void starts to be filled by growing dust particles
+
SUCCESSIVE GENERATIONSSUCCESSIVE GENERATIONSIN A SILANEIN A SILANE--BASED DISCHARGEBASED DISCHARGE
see also E.V. Johnson et al. Plasma Sources Sci. Technol. (2008)J.-C. Schauer
et al. Plasma Sources Sci. Technol. (2004)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
Time (s)
Amplitud
e (a
.u.)
M. Cavarroc, M. Mikikian, Y. Tessier, L. Boufendi, Phys. Rev. Lett. 100, 045001 (2008)
Correlation between electrical measurements, OES and LLS
Use of information from PKE-Nefedov
New dust particle generations emerge from inside the void
Confirmation by depositions performed at several distances
from electrode center
SEM analyses
+
SUCCESSIVE GENERATIONSSUCCESSIVE GENERATIONSIN A SILANEIN A SILANE--BASED DISCHARGEBASED DISCHARGE
see also E.V. Johnson et al. Plasma Sources Sci. Technol. (2008)J.-C. Schauer
et al. Plasma Sources Sci. Technol. (2004)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009M. Cavarroc, M. Mikikian, Y. Tessier, L. Boufendi, IEEE Trans. Plasma Sci. 36, 1016 (2008)
DEPOSITION OF DUST PARTICLESDEPOSITION OF DUST PARTICLESFROM DIFFERENT GENERATIONSFROM DIFFERENT GENERATIONS
Switching off the plasma when several generations coexistComplex dust cloud structure transferred to the deposition
Big (older) dust particles can be partly buried by new small dust
particles
Low sticking coefficient
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009M. Cavarroc, M. Mikikian, Y. Tessier, L. Boufendi, IEEE Trans. Plasma Sci. 36, 1016 (2008)
DEPOSITION OF DUST PARTICLESDEPOSITION OF DUST PARTICLESFROM DIFFERENT GENERATIONSFROM DIFFERENT GENERATIONS
Switching off the plasma when several generations coexistComplex dust cloud structure transferred to the deposition
Can be removed when venting too brutally the reactor to atmospheric
pressure
Useful (?) to see inner structure of the film
Big (older) dust particles can be partly buried by new small dust
particles
Low sticking coefficient
Wormhole to go back in time !!
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
50 100 150 200 250 300 350 400 4500
0.1
0.2
0.3
0.4
Tim e (s )
3H (a
.u.)
Tim e (s )
Freq
uenc
y (H
z)
50 100 150 200 250 300 350 400 450
52
54
56
58
60
3H (a.
u.)
Freq
uenc
y (H
z)
Time (s)
Time (s)Alternation of "high" and "less" ordered phases
High-ordered phasenew dust particle generation
Less-ordered phaseexpelling of big dust particles
Hypothesis: Void instability
SUCCESSIVE GENERATION INSTABILITIESSUCCESSIVE GENERATION INSTABILITIES
Appearance time:
a few seconds after plasma ignition
Frequency: range 40 -
60 Hz
Duration: whole plasma duration
M. Cavarroc, M. Mikikian, Y. Tessier, L. Boufendi, Phys. Plasmas 15, 103704 (2008)
Bumps: new generations
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
Very low frequency oscillation and rotation (sometimes !) of the
void regionVariant of the heartbeat instability ?
Heartbeat instability: see M. Mikikian
et al. New J. Phys. (2007), Phys. Rev. Lett. (2008)
INSTABILITIES DURING DUST PARTICLEINSTABILITIES DURING DUST PARTICLEFORMATION IN THE VOIDFORMATION IN THE VOID
M. Mikikian, L. Boufendi, A. Bouchoule, 30th
EPS, ECA Vol. 27A, p. O-3.1B (2003)
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
FORMATION OF DUST PARTICLES IN A PLASMAFORMATION OF DUST PARTICLES IN A PLASMAWhy ?Why ?Where ?Where ?
EVIDENCE AND DIAGNOSTICS OF DUST PARTICLE FORMATIONEVIDENCE AND DIAGNOSTICS OF DUST PARTICLE FORMATIONElectrical and optical measurementsElectrical and optical measurementsInstabilities induced by dust particle growthInstabilities induced by dust particle growthDesign of singleDesign of single--crystal silicon crystal silicon nanoparticlesnanoparticlesSuccessive generations of dust particlesSuccessive generations of dust particles
SUCCESSIVE GENERATIONS OF DUST PARTICLESSUCCESSIVE GENERATIONS OF DUST PARTICLESDustDust--free region: the voidfree region: the voidSuccessive generations from the voidSuccessive generations from the voidSuccessive generation instabilitiesSuccessive generation instabilitiesVoid instabilities ?Void instabilities ?
CONCLUSIONSCONCLUSIONS
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
CONCLUSIONSCONCLUSIONS
Many diagnostics can be used to detect and follow dust particle growthElectrical, Optical
Very important for the well-controlled design of nanoparticles
A high density of dust particles leads to plasma disturbance
Many different types of instabilities can be observed
Dust particle formation in plasma environments is relatively commonAstrophysics, Industry, Fusion
Control of dust particle formation is fundamental for applications
Dust particle formation is a cyclic phenomenonas long as precursors are provided
Dust-free spaces like the void play a crucial role
M. MIKIKIAN – DSDP2 – Kiel – September 4th 2009
THANK YOU
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