Ion Implantation in SiC:

1
Ion Implantation in SiC 365 MJ Target Spectra
S. Sharafat, M. Andersen, Hu Qiyang, and N.
Ghoniem University of California Los Angeles
Glenn Romanoski Oak Ridge National Laboratory
14th High Average Power Laser Program
WorkshopOak Ridge National LaboratoryOak Ridge,
TNMarch 21-22, 2006
2
OUTLINE

• Ion Implantation Issues (9 slides)
• Possible New Concepts for SiC/SiC (3 slides)
• Supportive Activities (2 slides)

3
R. Raffray, HAPL March 2006
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Implantation Calculation
SiC

• For each Ion
• Run SRIM at every energy
• Add all profiles ( weighted )

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Ion Implantation in SiC

• Sample Implantation Profiles using Perkins 365
  MJ Target Spectra (SRIM2003)
• Profiles for all ions, 1H, 2H, 3H, 3He, 4He,
  12C, 13C, Au, Pd were developed

Implantation Profile for 1H
Implantation Profile for 12C
Range
Range
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Ion appm (atomic parts per million) Profile in
SiC Per Shot
12C
12C
13C
13C
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Fraction of Ions at Mid-Bin Energy
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Ion Damage in SiC per Shot

• Ion Damage Profile (SRIM2003) for 1H, 2H, 3H,
  3He, 4He, 12C, 13C, Au, Pd

Vacancy Generation Profile for 4He
Vacancy Generation Profile for 12C
9
Ion Damage in SiC per Shot
10
Carbon Implantation and Formation of WC
Carbon Concentration Profile Evolution in W
13th HAPL Meeting
11
Formation of WC

• Carbon reacts with Tungsten to form WC and W2C
  inside the W-armor
• Complex model (1) Chemical reaction (2)
  Diffusion (3)T-swings (4) T-gradients.

• WC forms between 1150 and 1575 K
• W2C forms between 1575 and 1660 K

Solubility of C in W
D. Gupta, Met.Trans. A 1975

• Need for Experiments on WC
• Effect of H and He implantation on
• Mechanical Properties of WC
• Helium and Hydrogen Release
• Discussions with ORNL(G. Romanoski ) have
  identified testing facilities (G. Romanoski )

UCLA FusionNETWORK fusionNET.seas.ucla.edu

• At 2000 oC solubility of C in Tungsten is of the
  order of 0.05 at.

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Carbon Implantation in SiC
Implantation of 12C per shot

• Carbon Implantation range 1.75 mm
• For 10.1 m chamber implantation range has
  1x1026 SiC
• Number of C per shot 6.8x1019 C/shot

• After 1x106 shots (1.2 days) C/SiC ratio
  approaches unity (or SiC2) assuming no diffusion

• Concerns Regarding Excess Carbon in SiC
• Carbon diffuses readily (int.
  substit./detrapping)
• Carbon can bond chemically with H, D, and T
• Formation of Hydro-carbons CxHy ?T retention?

Huanchen, Ghoniem 1994

• Chemical Trapping of H, D, T slows down proton
  diffusion, defect annealing, and may interact
  synergistically with He
• Pursuing rate of Hydro-Carbon formation

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Hydrogen Implantation in SiC
Implantation of H, D, T
SEM micrograph image of blisters formed in the
6H-SiC irradiated at 300 K (1.0x1017 H/cm2) and
then annealed at 1070 K for 20 min. Jiang,
NIMB2000
HAPL365 MJ Target 10.1 m Chamber 1x1016 H/m2
Taguchi, JNM2004 Synergistic effect of H, He,
Si implantation Only He-implantation ? no
bubbles at 1300 oC (Timpl) Dual/Tripple (He, H,
Si) ? Helium bubbles formed at GB

• Roughening of SiC (HAPL conditions?)
• Effect of Chemical Trapping of H, D, T on
  roughening?
• Experiments H- He beam (HAPL conditions)?

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Possible New Concepts for SiC Armor

• Nanopillars and Dendrites
• Ion-Barrier Coating (IBC)
• Flexible Armor w/o Transpiration Cooling

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Possible New Concepts for SiC Armor Nanopillar

• Helium Implantation in CVD SiC26.3 MeV with 51
  degrader foils shows DENUDED ZONE 0.5 mm near
  Grain Boundary
• Poster by Hu Qyiang

Chen, Jung, Trinkaus, PRB 2000

• Nanopillars

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Possible New Concepts for SiC Armor Nanopillars
Dendrites
Dendrites
Cauliflower
Surface textures that were achieved in black W
coatings applied to W Ultramet 2005
High emissivity CVD dendritic Re coatings applied
to solid CVD Re surfaces Ultramet,2005

• Concept is based on
• Make use of characteristic diffusion length of
  helium (Denuded Zones in SiC 0.5 um)
• Choose materials which have lt1 um size features
  dendrites, pillars, cauliflower

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Possible New Concepts for SiC Armor IBC Coating

• The UEET (Ultra Efficient Engine Technology
  NASA) is developing SiC/SiC composites with EBC
• (EBC Environmental Barrier Coatings)
• EBC have low thermal k

Melt-Infiltrated SiC/SiC
New EBC with no degradation 300h, 1400oC (2552
F) 1h cycles, 90 H2O-bal O2
Doug Freitag301.570.3821dfreitag_at_ix.netcom.com4
April 2002

• Ion-Barrier Coating (IBC) SiC Armor

• Glass-forming materials have a relatively open
  crystal structure, which enhances ion release and
  self-healing.
• Is there a combination of high thermal
  conductivity materials that could be combined
  with glass forming materials. (Si3Ni4-MoSi2,
  Si3N4-SiC, SiOxNyBz ) that will allow for high
  release of implanted ions ?

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Possible New Concepts for SiC Armor Flexible w/o
Transpiration Cooling

• Use a Flexible Fibers
• No matrix material
• Fibers should be few microns in diameter to
  enhance Ion-release
• Keep armor flexible to accommodate loads

• Concern
• Thermal conduction path of the weave to
  underlying structure.

Sylramic SiC Fiber 2-D Weave

• Flexibel SiC-Fiber 2/3-D Weave Armor with
  Transpiration Cooling

• Wetted-Solid ?Evaporative Cooling
• Wick sufficient liquid to serve as a sacrificial
  layer to take care of all ions
• Use structure (W-fibers, dendrites, nanopillars,
  nano-grains) to hold liquid and to conduct heat

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OUTLINE

• Ion Implantation Issues (9 slides)
• Possible New Concepts for SiC/SiC (3 slides)
• Supportive Activities (2 slides)

20
FusionNET Database Update

• A new category has been added to FusionNET
• ITER Materials Handbook
• All ITER Tungsten Properties are available
• Density Electrical Resistivity
  Emissivity Enthalpy Fatigue S-N Curve
  Poisson's Ratio Reduction in Area Specific
  Heat Tensile Strength Thermal Conductivity
  Thermal Expansion Total Elongation Uniform
  Elongation Vapor Pressure Yield Strength
  Young's Modulus
• ITER Li, Be, ClidCop, 316 (LN)IG being uploaded

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HiCAT- A Novel In-situ Mass Loss Diagnostic Tool
L. Schmitz, P. Calderoni, Y. Tashima, A. Ying
(MAE-UCLA)

• A compact (15 mm diam.), high power hollow
  pulsed cathode discharge has been developed to
  ionize vaporized/ablated chamber wall material.
• Quantitative spectroscopy is used to determine
• Species Composition, and
• Density of ablated/vaporized material
• High sensitivity, high time resolution detection
  (lt 100 ns)
• Operation in Argon background gas (0.01-10 torr)
  or as vacuum arc
• Studied Chamber clearing in Z-Pinch

Measured Lithium density compared to vapor
pressure equilibrium density (pAr 0.3 torr) L.
Schmitz et al., J Nucl. Mat. 337-339 (2005) 1096
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Summary and Conclusions
Ion Implantation Busy implantation region
(10-20 mm in SiC lt 5 mm in W) Synergy of
implanted H and He (He-trapping, SiC, W)
Chemical interaction of excess carbon with H,
D, T (SiC, W) WC formation is favored because
of low solubility and large negative Gibbs Free
Energy of Formation Roughening of SiC due to
low energy H implantation Concepts
Nanopillars/Dendrites lt 1um to enhance ion
release from SiC IBC Ion-Barrier Coating with
glass formers to enhance ion release Flexible
(fiber) w/o Transpiration cooling Supportive
Activities FusionNET ITER MPH Tungsten
have been added to FusionNET Mass Loss
Analyzer In-situ mass-loss analyzer (scan rate
gt100 ns).
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• Background Slides

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Ion Implantation Profile in SiC per Shot
12C
12C
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From J. Perkins HAPL 365 MJ Target
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HiCAT Pulsed High Power Operation
Ar Ion Lines
Ar Neutral Lines

• High density, nearly fully ionized plasma (n lt
  1017 cm-3, kTe lt 2 eV) with local thermodynamic
  equilibrium (LTE) allows simplified spectroscopic
  determination of plasma parameters needed to
  interpret materials spectra.
• A Rapid sequence of pulses allows high time
  resolution (lt 100 ns) analysis of mass loss,
  ablated/vaporized material density, and species
  composition.
• Works in Argon background or as vacuum arc.

Z-BoxTest Chamber (Vacuum Capable Glove Box)
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HiCAT Diagnostics (Continuous operation)
Plasma Parameters obtained from Probe data
Schematic showing spectroscopy and Langmuir probe
set-up
Low current, low plasma density minimally
invasive diagnostics highest trace detection
sensitivity under equilibrium conditions.
Required back-ground pressure 0.01-10 torr Argon
Emission Spectrum
End-on View of HC Discharge in Argon
Ar neutral lines
Ar Ion lines
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Density Profiles (SRIM)
DEBRIS-IONS
12th HAPL Meeting
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Impact of Carbon Implantation Tritium Retention

• High T implantation 2x1017 T/m2 per shot
  for a R10.1 m chamber.
• Effects of Carbon on T retention at High
  Temperatures?

Irradiated tungsten at 653K with carbon
concentration as a parameter (1 keV 7 1024 H/m2
Ueda,2004.
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Self-Damage (Defect) Rate Profiles (SRIM)