Molecular dynamics Molecular dynamics investigation to identify investigation to identify Al atomic behavior on Al atomic behavior on various Cu surfaces various Cu surfaces 2007. 2. 6 김김김 1,2 , 김김김 3 , M. Sahashi 4 , 김김김 1 , 김김김 2 1 김김김김김김김김김 김김김김김김 , 2 김김김김김 김김김김김김 3 김김김김김 김김김김김김 , 4 Dept. of Electronic Eng., Tohoku University
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Molecular dynamics investigation to identify Al atomic behavior on various Cu surfaces
Molecular dynamics investigation to identify Al atomic behavior on various Cu surfaces. 2007. 2. 6 김상필 1,2 , 김영근 3 , M. Sahashi 4 , 이광렬 1 , 정용재 2 1 한국과학기술연구원 계산과학센터 , 2 한양대학교 신소재공학부 3 고려대학교 신소재공학부 , 4 Dept. of Electronic Eng., Tohoku University. - PowerPoint PPT Presentation
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Molecular dynamics investigation Molecular dynamics investigation to identify Al atomic behavior on to identify Al atomic behavior on
various Cu surfacesvarious Cu surfaces
2007. 2. 6
김상필 1,2, 김영근 3, M. Sahashi4, 이광렬 1, 정용재 2
1 한국과학기술연구원 계산과학센터 , 2 한양대학교 신소재공학부3 고려대학교 신소재공학부 , 4Dept. of Electronic Eng., Tohoku University
Atomic-scale Thin Film GrowthAtomic-scale Thin Film Growth
As the scale of device goes down to an atomic level…
a
b
ES* barrier
Various & complex diffusion behaviors
Conventional concepts
- Downward funneling model PRL 62, 921 (1989).
- Transient mobility model PRB 41, 5410 (1990).
- Impact cascade diffusion model PRB 57, 6685 (1998).
EAM Potentials for Al-Cu System*EAM Potentials for Al-Cu System*
ao (Å) Ecoh (eV) Bulk M. (GPa)
Al (FCC)
4.05035 (~0.01%)
3.31876(-1.23%)
75.565(-0.57%)
Al3Cu(L12)
3.9025(-0.97%)
3.47614 84.542
AlCu(L10)
3.75912(-1.93%)
3.59907 98.7448
AlCu3
(L12)
3.65454(-1.87%)
3.64548 117.274
Cu(FCC)
3.61503(~0.001%)
3.5241(-0.45%)
139.8872(-0.08%)
L12
L10
FCC
“Simple analytic embedded-atom-potential model including a long-range force for fcc metals and their alloys”, J.Cai and Y.Y. Ye, Phys. Rev. B 54 8398 (1996).
• Cu surface (100), (110), (111) (clean & with plateau surface)
• Substrate Temp. : 300K
• Incident Energy with normal incidence 0.1 eV
Normal incidence
Diffusion Energy Barrier CalculationsDiffusion Energy Barrier Calculations
Molecular Statics
Molecular Dynamics (MD)
MD results(position, path) Following the diffusion path
0 5 10 15 20-2,402.95
-2,402.94
-2,402.93
-2,402.92
-2,402.91
-2,402.90
-2,402.89
-2,402.88
-2,402.87
-2,402.86
To
tal
En
erg
y [e
V]
Reaction Path
0.5ML Al on Cu(100)0.5ML Al on Cu(100)
With plateauClean surface
Cu surface atoms Cu plateau atoms Al deposit atoms
Energy Barriers for Surface Diffusion* – (100)Energy Barriers for Surface Diffusion* – (100)
B1: Surface diffusionB2: Away from the stepB3: Toward the stepB4: Along the stepB5: Upward diffusionB6: Away from the step on plateauB7: Along the step on plateauB8: Downward diffusionB9: Ehrlich-Schwoebel (ES)
W. Zhu et al., PRL 92, 106102 (2004), S. Durunkanoglu et al., PRB 73, 125426 (2006),X.F. Gong et al., TSF 493. 146 (2005), H. Yildirim et al., Surf. Sci. 600, 484 (2006).*Various Surface Barriers
Energy Barriers for Surface DiffusionEnergy Barriers for Surface Diffusion
Step & Plateau
0.5ML Al on Cu(111)0.5ML Al on Cu(111)
With plateauClean surface
Cu surface atoms Cu plateau atoms Al deposit atoms
B1: Surface diffusion for fcc hcp siteB2: Surface diffusion for hcp fcc siteB3: Along the stepB4: Away from the step (two steps)B5: Toward the stepB6: Away from the step on plateauB7: Ehrlich-Schwoebel (ES) barrierB8: Downward diffusionB9: Upward diffusion
B1 B2 B3 B4 B5* B6 B7 B8 B9
0.055 0.055 0.308 0.638 - 0.018 0.331 0.106 0.317
B1
B3 B4
B6
B7
B8
B9
Energy Barrier [eV]
* Spontaneous reaction
B5
Energy Barriers for Surface Diffusion – (111)Energy Barriers for Surface Diffusion – (111)
B1 B2 B3 B4 B5* B6 B7 B8 B9
0.055 0.055 0.308 0.638 - 0.018 0.331 0.106 0.317
B1
B3 B4
* Spontaneous reaction
B5
Energy Barriers for Surface DiffusionEnergy Barriers for Surface Diffusion
Surface & Step
B1 B2 B3 B4 B5* B6 B7 B8 B9
0.055 0.055 0.308 0.638 - 0.018 0.331 0.106 0.317
B6
B7
B8
B9
* Spontaneous reaction
Energy Barriers for Surface DiffusionEnergy Barriers for Surface Diffusion
Step & Plateau
Clean surface With plateau
0.5ML Al on Cu (110)0.5ML Al on Cu (110)
Cu surface atoms Cu plateau atoms & same height with plateau atoms
Al deposit atoms
B1: Perpendicular to the open channelB2: Along the open channelB3: Along the step (perpendicular to the open channel)B4: Away from the stepB5: Toward the stepB6: Upward diffusionB7: Along the step (along the open channel)B8: Along the open channel on the plateauB9: Perpendicular to the open channel on the plateauB10: Downward diffusionB11: Ehrlich-Schwoebel (ES) B12: Exchange