v a n c e d I o n B e a m T e c h n o l o g y , I n c . A Hermes-Epitek Company 1 Cascadescientif ic global analytical services Chicane Deceleration – Chicane Deceleration – Qualifying a new technique to Qualifying a new technique to control energy contamination control energy contamination Nick White, John Chen, Chris Mulcahy, Sukanta Biswas, Russ Gwilliam
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Advanced Ion Beam Technology, Inc. A Hermes-Epitek Company Cascadescientific global analytical services 1 Chicane Deceleration – Qualifying a new technique.
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Ad
v an
c ed
Ion
Be
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no l
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, In
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A Hermes-Epitek Company1Cascadescientific global analytical services
Chicane Deceleration –Chicane Deceleration –Qualifying a new technique to Qualifying a new technique to control energy contaminationcontrol energy contamination
Nick White, John Chen,
Chris Mulcahy, Sukanta Biswas,
Russ Gwilliam
Ad
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A Hermes-Epitek Company2Cascadescientific
global analytical services
IntroductionIntroduction
Implantation of high-current boron beams at 200eV for SDE with USJ
Goal: Preserve the advantages of conventional implanters while meeting productivity requirements: Use of established source materials and technologies Accurate dosimetry Precise angle control Robust charging control
Eliminate deep tails caused by energy contamination Quantify sources of variation
All profiles normalized to 8.00e14 total dose200eV B+ using chicane deceleration891eV BF2 drift for referenceRolling average to reduce noise, width varies from 0.01 to 0.1 nm with depth(or the differences cannot be discerned)SIMS O2+ 200eV 45 degrees(effective O+ energy is 71 eV)
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Discussion of 200eV dataDiscussion of 200eV data
First 0.5 nm: Surface is clean. Minimal oxide effects. Concentration as % of dose falls with dose
0.5-2.0 nm Concentration is slightly higher with higher dose Ion beam mixing during implant
>3 nm Effect of increased pressure is resolved Profile becomes ~0.23nm deeper
>4 nm Channeling is distinct; level is approx 1.23% Range of channeled ions is ~4nm deeper for 0.1% of dose
>10 nm No effect of pressure can be resolved Why does BF2 have a lower background?
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DiscussionDiscussion
Possible Sources of profile shifts and deep tails: Channeling
We used RBS to look for channeling Pilot experiments eliminated channeling as source of
background variation Our amorphization was complete
SIMS system background and SIMS knock-on BF2 has a much lower background
Does the fluorine inhibit SIMS knock-on?
Higher energy beam components Neutralization close to exit of chicane
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What contaminants get past the chicane?What contaminants get past the chicane?
Zone of possibleEnergy contamination
Ions can be neutralized within the chicane
This process must occur within the exit zone if the contaminant is to reach the wafer
The electric potentials limit the maximum energy contamination to a fraction of final energy Proportional to pressure
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-0.5
0
0.5
1
0 5 10 15
Depth, nanometers
Shi
ft in
dep
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o P
R, n
anom
eter
s
Noisy due to backgroundbelow 1e18
Highly resolved dopant shiftHighly resolved dopant shiftdue to PR outgassingdue to PR outgassing
-Obtained by subtracting SIMS from PR wafer from SIMS from bare wafer after re-normalizing-Dose on PR wafer was 5% lower due to beam neutralization and loss
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USJ Implants using BFUSJ Implants using BF22
1.0E+16
1.0E+17
1.0E+18
1.0E+19
1.0E+20
1.0E+21
1.0E+22
0 1 2 3 4 5 6 7 8 9 10
Depth, nanometers
24 - BF2 891eV drift
29 - BF2 200eV PAI chicane
30 - BF2 200eV channeled chicane
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USJ Implants using BFUSJ Implants using BF22, smoothed, smoothed
1.0E+16
1.0E+17
1.0E+18
1.0E+19
1.0E+20
1.0E+21
1.0E+22
0 2 4 6 8 10 12
Depth, nanometers
24 - BF2 891eV PAI drift
26 - BF2 891eV PAI Chicane
27 - BF2 400eV PAI chicane
28 - BF2 400eV Channeled chicane
29 - BF2 200eV PAI Chicane
30 - BF2 200eV Channeled Chicane
24
29
30
Normalized to 5E14Smoothed using moving averageof increasing width from 0.01 to 0.1 nm
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Conclusions:Conclusions:
Chicane technique can deliver ~70 wph at 200eV B 5e14 with Xj (unannealed) of < 7 nm Magnitude of energy contamination is ~22eV, or < 0.3 nm
Channeling can modify the as-implanted profile by ~ 3nm Metrology must resolve 3nm! PAI required
Chicane technique can deliver ~100 wph of 891eV BF2 5e14 May have tighter profile and less diffusion PAI required
Chicane technique can deliver ~33 wph for 200eV BF2 5e14 with Xj (unannealed) of < 5 nm
Does not require PAI
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A Hermes-Epitek Company27Cascadescientific
global analytical services
Acknowledgements:Acknowledgements:
Implants and beam measurements: Ed Petersen Yap Han Chang