Ion Implantation and Temperature HEROS Modeling

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Ion Implantation and Temperature ? HEROS
Modeling

• Qiyang Hu , Shahram Sharafat, Nasr Ghoniem
• Mechanical Aerospace Engineering
• University of California, Los Angeles
• San Diego, Aug 8th, 2006

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Objectives

• Calibrate HEROS with a wide range of
  applications
• Deep implantation in pulses by UNC
• Shallow implantation in steady states by IEC
  condition
• Shallow implantation in steady states by
  Nishijima04

Leads to confidence in predicting IFE conditions
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• HEROS Code Improvement
• Simulation Discussion
• Conclusions and Future Plans

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Previous HEROS code has serious numerical
instability problems

• In most cases
• Time to be simulated lt 10 ?sec
• Running Time gt 6 hours
• Time step gt 2000 steps
• Temperature range lt 2000 K

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HEROS model is improved

• Still, reaction-diffusion rate equation
• Simplify the equation
• Ignore some cluster effects
• (e.g. vacancy clusters, interstitial clusters
  etc.)
• 18 variables/equations ? 13
• Ignore bubble coalescence

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HEROS numerical scheme
Temperature profile
Within a bin, each C(i) isin an average sense
Implantation profile

W back
variable bin size
W front
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Recent Progresses in Modeling Helium Behavior

• Can integrate equations for thousands of pulses.
• Can include rapid temperature transients.
• Aim to calibrate model with experimental data.

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• HEROS Code Improvement
• Simulation Discussions
• Conclusions and Future Plans

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First, we want to use our new HEROS code to model
UNC(05) UWM(04) conditions.
We re-simulated UNC UWMs implantation cases
Helium Implantation
Damage
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UNCs Temperature Profile
(?C)
( L. Sneed,2005 )
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After 1 cycle of 1019 He/m2
Temperature ?C
2000?C
850?C
3000
3060
Time (sec)
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After 10 cycle of 1018 He/m2/cycle
Temperature ?C
2000?C
850?C
360
300
720
Time (sec)
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After 100 cycle of 1017 He/m2/cycle
Temperature ?C
2000?C
850?C
90
30
180
Time (sec)
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After 1000 cycle of 1016 He/m2/cycle
Temperature ?C
2000?C
850?C
63
3
126
Time (sec)
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Helium Retention
Diffuse too fast in HEROS
Short pulse OK!
Cycles
1000
100
10
1
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Bubble Radius Movies HEROS also gives the
spatial distribution information
Bin Number20 Total width10?m
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For UWMs IEC conditions Some notes before
comparisons

• Surface bubble ? Surface pore
• Surface bubble density ? (volume bubble
  densitysurf)2/3
• We focus on steady condition.

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New HEROS code is stable and gives the
information about bubble (pore) sizes
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So does the pore density
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We also calibrate our model by Nishijima groups
experiments (ITER)
Temperature 1950 ?C
Gh
1?m
x
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HEROS also gives the spatial distribution
information (average sense)
Bin Number20 Total width10?m
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HEROS for temperature modeling
Surface Heating
Emissive effect can be ignored
B.C.
Max
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• HEROS Code Improvement
• Simulation Discussion
• Conclusions and Future Plans

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Conclusions

• Capabilities of HEROs code are largely improved
• Our HEROS can integrate equations
• with thousands of pulses.
• with rapid temperature transients.
• Need to improve
• Helium More trapping mechanism
• Heat new mechanism

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Planning on HEROS

• Implement recent pulsed conditions
• UWM
• UNC
• Implement IFE conditions
• Add bubble coalescence
• Exceed the 0-order (average) description
• Temperature/carbon diffusion problem

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We wish to develop a unified temperature/diffusion
/microstructure code

• Containing
• Temperature transients
• Helium distribution
• Carbon distribution
• Point defect/displacement damage

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Thanks!
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Backup Slides
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Helium retention for IEC condition
Most of He are in grain boundary