Oct 12, 2015
1Constantin VahlasSOPRANO Meeting, Caen, 17 July 20091
Chemical Vapour Deposition of Metallic Films:from Unary Systems to Complex Intermetallics
Constantin Vahlas
Institut Carnot CIRIMAT
Toulouse
Constantin VahlasSOPRANO Meeting, Caen, 17 July 20092
CVD: one of the most important methods for preparingmetallic and ceramic thin films and coatings
Protection (corrosion, wear)
Optical properties
Electronic properties
Magnetic properties
Decoration
New hybrid- properties
Constantin VahlasSOPRANO Meeting, Caen, 17 July 20093
CVD coated steel tools
Segmented forming tool for automobile door
Drawing ring
Constantin VahlasSOPRANO Meeting, Caen, 17 July 20094
Outline
Definitions
Reactors
Precursors
Precursors delivery systems
Surface events
Conformal deposition
Selectivity
Infiltration of preforms
Deposition on powders
Competitive reactions
Towards MOCVD processed metallic alloy coatings: the Al-Cu-Fe system
Concluding remarks
Constantin VahlasSOPRANO Meeting, Caen, 17 July 20095
Definitions
Constantin VahlasSOPRANO Meeting, Caen, 17 July 20096
Chemical Vapor Deposition: The general frame
Chemical vapor deposition is a process where one
or more volatile precursors are transported via the
vapour phase to the reaction chamber, where they are
decomposed on a heated substrate to produce high-
purity, high-performance solid materials.
Precursor: person or thing that comes before sth.
(Oxford Advanced Dictionary, 1989)
Halide
Molecular compound (MOCVD)
2Constantin VahlasSOPRANO Meeting, Caen, 17 July 20097
+
Main gas flow region
AdsorptionSurface reaction Diffusion
Dsorption
NucleationGrowth
LigandMetallic centre
Transport
Diffusion
Gas phase reaction
+
Formation of
precursor vapors
Vaporization
Sublimation
Liquid injection
Diagnostics:
- Gas phase
- Surface
Reactor
Configuration
& design
- Growth rate
- -structure
- Composition
- Phases
- Adhesion
Post deposition
Thermal treatments
Properties
Modelling:
- Reactor
- Transport phenomena
- Deposition chemistry
- Surface electronic properties
Substrate
The MOCVD process: a sequence of elemental steps which have to be understood, controlled and optimized
Selection of
molecular
precursors
Vapor pressure
Stability
Shelf life
Dissociation scheme
Synthesis
Cost
Environment
Constantin VahlasSOPRANO Meeting, Caen, 17 July 20098
Chemistry in Chemical Vapor Deposition
In every CVD process, there is some path involving physical phenomena AND a reaction that converts the vapors to a solid.
Part of the task of designing the reactor and process is always to force this reaction to happen only where and when it is desired (typically on the substrate), and not everywhere else.
Undesired reactions result in particles which can fall onto the substrates, coating of chamber walls, and clogging of exhaust openings.
The approaches to achieving this selectivity typically rely on five levers:
Precursors chemistry
Temperature
Time
Pressure
Surface specificity.
+
AdsorptionSurface reaction Diffusion
Dsorption
NucleationGrowth
TransportTransport
Diffusion
Gas phase reaction
+
Substrate
Constantin VahlasSOPRANO Meeting, Caen, 17 July 20099
No universal processing technique available!
Minimum waste
Access to all metals
High throughputLower substrate T
Conformal coverageEase of development
CVDPVD
Advantages
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200910
Reactors
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200911
Reactors
Gas phase introduction
By products & pressuremanagement
Deposition chamber
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200912
Low pressure UV Hg lamp
Air cooling
LN2 trap
B
h
Process activation
Thermal
Plasma
Photoactivation
Laser
Jian Mi, PhD thesis, Georgia Tech, 2006 S. Vidal, PhD thesis, Toulouse Natl. Pol. Inst, 2001
(hfa)Cu(COD)272 nm
3Constantin VahlasSOPRANO Meeting, Caen, 17 July 200913
CVD Reactor types 1: Hot wall
Precursor
inlet
higher throughput
large heated
surface area
precursor depletion
Unreacted
precursor
& byproducts
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200914
CVD Reactor types 2: Cold wall
better control of uniformity
lower throughput
Precursor
inlet
Unreacted
precursor
& byproducts
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200915
Moving the wafers at constant speed through a heated reactor chamber
Install CVD processes at appropriate positions in steel or glass facilities.
Controlled by temperature, process gas flow rate, and belt speed.
High growth rates High equipment throughput Good uniformity Capability to process large-
diameter wafers
CVD reactor types 3: Atmospheric pressure, conveyor belt or continuous flow reactors
Particulate formation from gas-phase
nucleation
High gas consumption
Requests frequent reactor cleaning
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200916
CVD reactor types 4: Coating parts in FBCVD reactors
Treating agent: inert oxide (the filler: Al2O3, SiO2, ZrO2, TiO2) + powder of source metal (the donor of the element to be coated)
Fluidizing gas: Inert gas + activator (halides, alcali metal halides)
Donor + activator vapor precursors of the coating forming element (3HCl + Al AlCl3+ 1.5 H2)
Kinkel et al., Steel Res. 1995, 66, 318
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200917
High T (>1000K), diffusion of the substrate material
Substrate: Ni
Donor: FeAl
Activator: NH4Cl
Coating: NiAl
Voudouris & Angelopoulos, High Temp. Mater. Process. 1998, 2, 165
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200918
Different types of reactors, depending on: The type of activation (thermal, plasma, photon)
The geometry (vertical, horizontal)
The activated parts (hot, cold wall)
The best choice of a films deposition technique depends on targeted application
In the case CVD is foreseen as the best solution, the optimum choice of the reactor configuration still depends on the particular specifications
4Constantin VahlasSOPRANO Meeting, Caen, 17 July 200919
Temperature related growth rate:the three main regions of the Arrhenius plot
T-1 / K-1
127 C
29
30
31
32
33
34
0.0005 0.0010 0.0015 0.0020 0.0025
Ln(growth rate / m
oleculecm
-2s
-1)
227 C394 C727 C1727 CFlux limited kinetics
Surfacereactionratelimitedkinetics
Competingprocesses
Taylor et al., J. Am. Chem. Soc., 1999, 121, 5220
+
AdsorptionSurface reaction Diffusion
Dsorption
NucleationGrowth
TransportTransport
Diffusion
Gas phase reaction
+
Substrate
TiO2 from Ti(OiPr)4
Ea
Ea: the minimum energy necessary for a specific chemical reaction to occur
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200920
Precursors
+
LigandMetallic centre
+
Substrate
Selection of
molecular
precursors
Vapor pressure
Stability
Shelf life
Dissociation scheme
Synthesis
Cost
Environment
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200921
Chemical Vapor Deposition: CVD depends on the availability of a volatile chemical which can be converted by some reaction into the desired solid film. What makes the vapors (that is, volatility)
How these vapors can react in the gas phase or on the surfaces to be converted into the film?
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200922
Evolution: larger possibilities, smaller scales, highercomplexity
Traditionnal CVD: Halogenide precursors (WF6, TiCl4, SiH2Cl2)
T > 700 C, limited possibilities
Metal-organic CVD & Organometallic CVD: Molecular compounds
Tamb < T < 600 C, numerous
possibilities, high complexity
W
C
C C
C
C
C
O
O
O
O
O
O
H
Al
Me2EtN H
H
+
AdsorptionSurface reaction Diffusion
Dsorption
NucleationGrowth
Transport
Diffusion
Gas phase reaction
+
Substrate
+
AdsorptionSurface reaction Diffusion
Dsorption
NucleationGrowth
TransportTransport
Diffusion
Gas phase reaction
+
Substrate
Butterf
ly chem
istry
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200923
Co-deposition: Specific criteria
Compatibility of transport & deposition conditions (e.g. T)
No gas phase interaction
Compatible surface chemistry
+
AdsorptionSurface reaction Diffusion
Dsorption
NucleationGrowth
Transport
Diffusion
Gas phase reaction
+
Substrate
+
AdsorptionSurface reaction Diffusion
Dsorption
NucleationGrowth
TransportTransport
Diffusion
Gas phase reaction
+
Substrate
The difference between a molecular compound and a metalorganic precursor
Molecular precursors:Compatibility, Transport properties
CVD
Microstructure
Optimizationmaterial/process
Quantum chemistry,thermochemistry,chimique chemical
kinetics
Properties
Diagnostics
Qualification
General criteria
Liquid rather than gas or solid
Convenient volatility
Thermal stability
High purity or easily purified
Long shelf life
Easy & clean decomposition on the substrate
Non toxic
Environmentally compatible
Low cost
impossible
to meet all crite
ria
Mau
ry, J. Phys. IV, C5, 1995, 449
CMA NoE
, 200
5 -
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200924
Precursor architecture: a major issue
Molecular Structure and Bonding Controls: Precursor Volatility Deposition kinetics Growth rate Composition -structure
H
Al
Me2EtN H
H
H
Al
Me3N H
H
Solid
(AlH3-TMA)ads (AlH3)ads + (TMA)adsAlH3,ads Alads + 3Hads3Hads 1.5H3,ads 1.5H3,g
Liquid
(AlH3-DMEA)ads AlH3,ads + (DMEA)adsAlH3,ads Alads + 3Hads3Hads 1.5H3,ads 1.5H3,g
Dubois et al. Surf. Sci. 1990, 236, 77 Kim et al. Appl. Phys. Lett. 1990, 236, 77
5Constantin VahlasSOPRANO Meeting, Caen, 17 July 200925
Vahlas & Brissonneau, Annales Chimie, Sci. Mater., 2000, 25, 81
Various solutions for various constraints
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200926
MOCVD of Re: a processing route beyond the state of the art
Re: interesting material for high T applications in structural systems and energy
High Tf (3453K), low vapor pressure @Tf (0.1 Pa @ 3073K), mechanical properties x2 those of W and Mo up to 1473K, excellent corrosion & fretting resistance @ high T (2nd to Os)
Elevated cost
Heterogeneous catalysis, heat exchangers, space and missiles propulsion, hot gas valves Sherman, et al., JOM., 1991, 20
Bryskin and Danek, JOM., 1991, 24
Re coatings:
Powder metallurgy: too expensive, too long, no net shape
High T CVD: ReF6 + H2, ~800 C, handling of fluorides and effluents
ReCl5 + H2, ~1200 C, non compact -structure
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200927
Transport behavior of Re2(CO)10
Important weight loss @ 503K : complete sublimation
Endothermic peak @ 503K : either decomposition and/or vaporization
Two small endothermic peaks @ 374K and 465K. Either crystallographic transformation or monomerization (supplier: 443K)
DTA
TGA
F. Juarez-Lopez, PhD thesis,
Toulouse Natl. Pol. Inst, 2005
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200928
Time (min)
0 200 400 600 800 1000
P (Pa)
0
100
200
300
400
500
600
425K (152 C)
381K (108 C)
397K (124 C)
Intense increase of P with t
Stabilized P @ 108 C:no decomposition
Saturated vapor pressure of Re2(CO)10
Slight increase of P with t
1/T (K)
0,0024 0,0026 0,0028 0,0030 0,0032
log10P(Torr)
-2
-1
0
1
152 C
108 C
72 C
54 C 40 C
33 C
124 C
log10P (torr) = - 3116,7/T(K) + 7,9689
Juarez et al., Electrochem. Soc. PV 2003-08, 538
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200929
T=408 C
P=1 atm
50 nm50 nm
Original, low-T process for Re films
10 m
Lafont, et al., Scripta Mat., 2004, 51(7), 699
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200930
Molecular compounds provide a much wider spectrum of use than traditional halide compounds
A long list of criteria for the qualification of a compound as a precursor for a CVD process
Extremely difficult if not impossible to satisfy all criteria: compromise
No universal precursor for all processes involving deposition of a given metal: one precursor for each application?
6Constantin VahlasSOPRANO Meeting, Caen, 17 July 200931
Precursor delivery systems
+
LigandMetallic centre
+
Formation of
precursor vapors
Vaporization
Sublimation
Liquid injection
Substrate
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200932
N2 flow rate (sccm)
0 2000 4000 6000 8000 10000 12000
[Al(acac)
3] flow rate (g/h)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
5 g
10 g
20 g
50 g
100 g
150 g max
Bubblers
V
V
V
Carrier gas
H2 N2 Ar
Mass flow
controller
Bubbler - pure liquid
or solid precursor
Fpr = (FcgPT/Ptot)[1 exp(-Q/Fcg)]
110 m
m
40 mm
110 m
m
40 mm
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200933
Precursor Delivery Systems - Direct Liquid Injection
Precursor mass flow rate
Pumping rate
Precursor concentration
Vapor pressure
NikNikloclocnene
CobaltocCobaltocnene
TIBATIBA
ArAr
H2H2
evacuationevacuation
NikNikloclocnene
CobaltocCobaltocnene
TIBATIBA
ArAr
H2H2
evacuationevacuation
: Precision, reproducibility
: Use of solvents (process &
effluents management), incomplete
evaporation, limited solubility, use of
chlorinated ligands)Carrier gas
H2 N2 Ar
Mass flow
controller
Bubbler - precursor
& solvent
Pump Gasification
Carrier gas
H2 N2 Ar
Mass flow
controller
Bubbler - precursor
& solvent
Pump Gasificationwww.kemstream.com
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200934
Precursor Delivery Systems Sublimation in a fluidized bed
Vahlas et al., Chem. Vap. Dep., 2007, 13, 123
Rapid & efficient mixing (isothermal operation)
Continuous operation
Scale up
High mass & heat transfer rates
Under development
Dbit gaz vecteur (sccm)
0 2500 5000 7500 10000 12500
Dbit Prcurseur (g/h)
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
US Pat. 2008 268143(A1)
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200935
The objective: To generate the vapors and transport them to the deposition zone
Robust, reliable precursor feeding systems are necessary for the scaling up and the industrial implementation of a CVD process
Stable feeding rate vs deposition time
High feeding rate: In the diffusion limited regime
To avoid starving regime
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200936
Adsorption
Surface reaction Diffusion
NucleationGrowth
+
Substrate
Desorption
Definitions
Reactors
Precursors
Precursors delivery systems
Surface events
Conformal deposition
Selectivity
Infiltration of preforms
Deposition on powders
Competitive reactions
Towards MOCVD processed metallic alloy coatings: the Al-Cu-Fe system
Concluding remarks
7Constantin VahlasSOPRANO Meeting, Caen, 17 July 200937
Surface events 1: conformal deposition
Fully conformal 10 nm Cu seed-layer on TiN barrier in a 200 nm structure Constantin VahlasSOPRANO Meeting, Caen, 17 July 2009
38
Surface events 2: Selectivity
Preparing patterned metal films:
Blanket deposition + selective area etching
Blanket deposition into substrate trenches followed by chemical-mechanical polishing
Selective CVD
deposition of a material onto one surface (the growth surface) in the presence of another surface (the non-growth surface)
Cu on Si, not on SiO2
efficient
lessefficient
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200939
Mechanisms for selective deposition rely on:- inhibiting adsorption and reaction of the precursor and nucleation of the
metal on the non growth surface,- promoting these processes on the growth surface
1. Intrinsic reaction rate of the precursor on the non-growing surface slower than on the grow surface and on the growing film
2. The growth surface (e.g. Si) acts as a reducing agent and is selectively, sacrificially consumed by the precursor (e.g. WF6)
3. Dissociation of a co-reactant (a reducing agent, e.g. H2) occurs on the growth surface (e.g. a metal) but not on the adjacent non-growth surface (e.g. SiO2, polymer, metal oxide)
4. Rate increase on the growth surface by photo-chemically driven reactions
5. Selective passivation of the non-growth surface prevents adsorption of the precursor on the non-growth surface while adsorption and reaction occur on the growth surface
6. A species is present on the non-growth surface that getters (removes) the nucleating species
7. A free energy barrier for the formation of the metal nuclei inhibits nucleation on the non-growth surface; smaller barrier on the initial growth surface allowing for physical nucleation to occur
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200940
Surface events 3: infiltration of preforms; a case study
Potential technological applications & markets for a proprietary material developed by an SME :
Materials solutions for the air treatment in small volumes (passengerscabins in cars, space stations)
Catalytic converters made of metallic carriers
Catalytic support(e.g. -Al2O3) some 100 nm
Catalyst particles(e.g. Pt) some nm
some 10 msome 10 m
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200941
i. The substrate
SS, Cu, Ni = 19 mm e = 1 mm Porosity 50 and 70% Pores size 20 and 100 m BET = 0.5 2 m2/g SEF = 30 190 m2/m2
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200942
Al2O3 as a catalyst support
Levin & Brandon, J. Am. Ceram. Soc., 1995, 81(8), 1998-AlOOH -Al2O3
-Al2O3: convenient catalyst or catalytic supportLiu & Truitt, J. Am. Chem. Soc., 1998, 119, 9856
300 500 C
Impregnation of boehmite in vacuum
Calcination at 450C/4 h
Alphonse & Courty, Thermochim. Acta, 2005, 425, 75
8Constantin VahlasSOPRANO Meeting, Caen, 17 July 200943
Al2O3 covers the internal surface
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200944
Pt(acac)2 @(390 C, 50 Torr) Pt
Pt by F-MOCVI on Al2O3
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200945
Pt concentration higher at the entrance side of the disk and at its central part
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200946
200 nm200 nm200 nm
tdeposition = 60 min Pt = 4.5 wt % BET = 5 m2/g
High Pt load
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200947
100 nm100 nm100 nm
tdeposition = 10 min Pt = 0.3 wt % BET = 15 m2/g
Low Pt load
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200948
0
10
20
30
40
50
60
70
80
90
100
140 160 180 200 220 240 260
Temperature (oC)
CO conversion (%)
CO to CO2 conversion
O2/CO = 0.33
tcontact = 0,0053 s
T50 = 203C, 209C
- O2/CO = 0.5tcontact = 0.0400 sT50 = 199C
Cho et al., Cat. Lett., 2005, 103, 257
- O2/CO = 99/1tcontact = 0.0480 sT50 = 98C
Carberry et al, Cat. Lett., 1990, 4, 43
Similar catalytic activity for both loads
Christoglou et al., Surf. Coat. Tech., 2007, 201, 9195
Compares favorably with state of the art
9Constantin VahlasSOPRANO Meeting, Caen, 17 July 200949
Surface events 4: Deposition on powders
particle coatings for
nuclear applications
thick and continuous deposits on dense
(non-porous) powders
Large scale production of new classes of materials: supported catalysts,
nanomaterials
Vahlas et al. Mat. Sci. Eng. R 2006, 53, 1
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200950
CVD on powders: major differences from deposition on flat substrates
LARGE available surface:
surface reactions are so extended that gaseous precursors are very often totally consumed a few centimeters after their entrance into the fluidised-bed reactor in a laboratory scale contactor
compensated by vigorous mixing: uniform deposition
High heat transfer rates:
Isothermal conditions
Available growth surface per heated volume (m2/m3)
1e+1 1e+2 1e+3 1e+4 1e+5 1e+6 1e+7 1e+8
. FBCVD on porous particles
. CVI
. FBCVD on dense particles
. Hot wall multiwafer tubular
. Single wafer
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200951
Chemical engineering findings
The objective:
Each particle will present its entire surface to the gaseous reactants during the process
FB:
A bed of solid particles over a gas-distributing plate (often called the grid), is made to behave like a liquid by passing gas through it at a flow rate above a certain critical value
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200952
The Geldard diagram
Group A (20150 m, < 2 g/cm3) & B (sand): easy
Group D: large particles
Group C: cohesive
small size
strong electrostatic charges
wet, sticky non spherical materials
No sharp separation
Fluidization and powder classification:The basic principles
Crossing of the bed by the gas flow results in a pressure drop (P) through the bed ( essential information on the characteristics of the bed).
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200953
Improve the performance of gas turbines Increase combustion temperature
Increase components temperature
Risk of degradation
Superalloy
MCrAlY
Al2O
3-
YSZ
Hot Gas
Al2O3
Superalloy
MCrAlYMCrAlY
Al2O
3-
YSZYSZ
Hot Gas
Cooling Air
Therm
al Barrier
Superalloy
MCrAlYMCrAlY
Al2O
3-
YSZYSZ
Hot Gas
Al2O3
Superalloy
MCrAlYMCrAlY
Al2O
3-
YSZYSZ
Hot Gas
Cooling AirCooling Air
Therm
al Barrier
Application of a thermal barrier
Doping of the bond coats by different metals (Zr, Hf, Re, Ru) is beneficial to the mechanical and/or oxidation resistance of the barriers (e.g. Czech et al., Surf. Coat. Techn., 1995, 76-77, 28)
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200954
Praxair, NI-482 powders
50 m50 m
wt %Ni 42Co 23 Cr 20 Al 8Y 1Ta 5
High densitySpherical shapeAgglomeratesLarge size distribution Particles belonging to
groups C, A et B
NI-482 particles size (m)
10 100 1000
NI-4
82 particle
s
size distrib
ution (%
)
0
1
2
3
4
5
6
7
8
NI-482density
are off Geldarts classification
10
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200955
a
b
c
de
The MOCVD process requires fluidization in a spouted bed
0,00 0,01 0,02 0,03 0,04
0
200
400
600
800
1000
1200
1400
1600
1800
0,00 0,01 0,02 0,03 0,04
P (Pa)
0
200
400
600
800
1000
1200
1400
1600
1800
H/D=1,5
0,00 0,01 0,02 0,03 0,04
0
200
400
600
800
1000
1200
1400
1600
1800
Gas velocity (m/s)
0,00 0,01 0,02 0,03 0,04
P (Pa)
0
200
400
600
800
1000
1200
1400
1600
1800
H/D=1,5
0,00 0,01 0,02 0,03 0,04
0
200
400
600
800
1000
1200
1400
1600
1800
0,00 0,01 0,02 0,03 0,04
P (Pa)
0
200
400
600
800
1000
1200
1400
1600
1800
H/D=1,5
0,00 0,01 0,02 0,03 0,04
0
200
400
600
800
1000
1200
1400
1600
1800
Gas velocity (m/s)
0,00 0,01 0,02 0,03 0,04
P (Pa)
0
200
400
600
800
1000
1200
1400
1600
1800
H/D=1,5
which should be optimizedtaking into account the constraints of the powders
Caussat et al., Powder Techn., 2006, 165, 63
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200956
The design of the reactor considers the constraints both of the fluidization and of deposition
Filters
Grid (Powder beforespouting)
H2/ O2
N2Spouted bed
Frit Precursors: Ru(C5H5)2Re2(CO)10
SSteel reactor
Gas panel
Juarez et al., J. Phys. IV., 2001, 11, 1117
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200957
10 m
SEM EDS Ru
Deposition of Ru from RuCp2 + H2T = 898KQRuCP2 = 0,30 sccmQH2 = 428 sccmUgas > Ums
Vahlas et al., Chem. Vap. Dep., 2002, 4, 127
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200958
Theta (degrees)
10 20 30 40 50 60
Ru doped
NiCoCrAlY
Ru JCPDS 6-663
1 wt % Ru Well defined crystallites
50 nm50 nm50 nm50 nm
D1
D2
D3D4
D5
D1
D2
D3D4
D5
D (cm) dexp (nm) Plane dJCPDS #6-663
1 0,85 0,235 100 0,2343
2 1,0 0,211 002 0,2142
3 1,28 0,205 101 0,2056
4 1,68 0,157 102 0,1581
5 2,10 0,119 103 0,1219
C contamination: C/Ru=4
Lafont et al., Scripta Mat., 2004, 51(7), 699
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200959
10 mSEM QSB
EDS Ru
Homogeneous distribution of the deposit Ru 0,90 wt % No C contamination
Deposition from RuCp2 + O2T = 523KQRuCP2 = 0,36 sccmQO2 = 160 sccm
Constantin VahlasSOPRANO Meeting, Caen, 17 July 200960
Continuous film, composed of ~30 nm crystallites
100 nm100 nm100 nm100 nm
50 nm50 nm50 nm50 nm