Ab-Initio Pseudopotential Calculations of Boron Diffusion in Silicon

1999 ◽  
Vol 568 ◽  
Author(s):  
W. Windl ◽  
M. M. Bunea ◽  
R. Stumpf ◽  
S. T. Dunham ◽  
M. P. Masquelier
Keyword(s):  
Fermi Level ◽  
Ab Initio ◽  
Diffusion Length ◽  
Crystalline Silicon ◽  
Boron Diffusion ◽  
Elastic Band ◽  
Pseudopotential Calculations ◽  
Band Method ◽  
Diffusion Paths ◽  
And Diffusion

ABSTRACTIn this work we investigate boron diffusion as a function of the Fermi-level position in crystalline silicon using ab-initio calculations and the nudged elastic band method to optimize diffusion paths. Based on our results, a new mechanism for B diffusion mediated by Si self-interstitials is proposed. We find a two-step diffusion process for all Fermi-level positions, which suggests a kick-out with a directly following kick-in process without extensive B diffusion on interstitial sites in-between. Our activation energy of 3.47 – 3.75 eV and diffusion-length exponent of -0.55 to -0.18 eV are in excellent agreement with experiment.

scholarly journals Effects of Aluminum on Hydrogen Solubility and Diffusion in Deformed Fe-Mn Alloys

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
C. Hüter ◽  
S. Dang ◽  
X. Zhang ◽  
A. Glensk ◽  
R. Spatschek
Keyword(s):  
Ab Initio ◽  
Equilibrium Model ◽  
Hydrogen Diffusion ◽  
Local Equilibrium ◽  
Minimum Energy ◽  
Trap Site ◽  
Elastic Band ◽  
Band Method ◽  
Minimum Energy Paths ◽  
And Diffusion

We discuss hydrogen diffusion and solubility in aluminum alloyed Fe-Mn alloys. The systems of interest are subjected to tetragonal and isotropic deformations. Based onab initiomodelling, we calculate solution energies and then employ Oriani’s theory which reflects the influence of Al alloying via trap site diffusion. This local equilibrium model is complemented by qualitative considerations of Einstein diffusion. Therefore, we apply the climbing image nudged elastic band method to compute the minimum energy paths and energy barriers for hydrogen diffusion. Both for diffusivity and solubility of hydrogen, we find that the influence of the substitutional Al atom has both local chemical and nonlocal volumetric contributions.

Ab initio investigation of boron diffusion paths in germanium

2006 ◽  
Vol 18 (7) ◽  
pp. 775-780 ◽  
Author(s):  
C. Janke ◽  
R. Jones ◽  
S. Öberg ◽  
P. R. Briddon
Keyword(s):  
Ab Initio ◽  
Boron Diffusion ◽  
Diffusion Paths

AB Initio Pseudopotential Calculations of Dopant Diffusion in SI

1997 ◽  
Vol 469 ◽  
Author(s):  
Jing Zhu
Keyword(s):  
Ab Initio ◽  
Degrees Of Freedom ◽  
Quantitative Description ◽  
Carbon Diffusion ◽  
Boron Diffusion ◽  
Electron Charge Density ◽  
Numerical Convergence ◽  
Enhanced Diffusion ◽  
Pseudopotential Calculations ◽  
Consistent Treatment

ABSTRACTThe ab initio pseudopotential method is used to study transient-enhanced-diffusion (TED) related processes. The electronic degrees of freedom are included explicitly, together with the fully self-consistent treatment of the electron charge density. A large supercell and a fine k-point mesh are used to ensure numerical convergence. Such method has been demonstrated to give quantitative description of defect energetics. We will show that boron diffusion is significantly enhanced in the presence of the Si interstitial due to the substantial lowering of the migrational barrier through a kick-out mechanism. The resulting mobile boron can also be trapped by another substitutional boron, forming an immobile and electrically inactive two-boron pair. Similarly, carbon diffusion is also enhanced significantly due to the pairing with Si interstitiels. However, carbon binds to Si interstitials much more strongly than boron does, taking away most Si interstitials from boron at sufficiently large carbon concentration, which causes the suppression of the boron TED. We will also show that Fermi level effect plays an important role in both Si intersititial and boron diffusion.

Saddle Point Energies from Ab Initio Jump Profiles in MC Simulation of Order Kinetics in Intermetallics.

2011 ◽  
Vol 172-174 ◽  
pp. 1022-1027
Author(s):  
Martin Leitner ◽  
Doris Vogtenhuber ◽  
Wolfgang Pfeiler ◽  
Wolfgang Püschl
Keyword(s):  
Transition State ◽  
Saddle Point ◽  
Ab Initio ◽  
Kinetic Monte Carlo ◽  
Energy Difference ◽  
State Theory ◽  
Elastic Band ◽  
Treat Ment ◽  
Band Method ◽  
Mc Simulation

Kinetic Monte Carlo (KMC) simulation is a valuable tool to investigate configu-ration changes in intermetallic compounds. The elementary process is the jump of an atomfrom a lattice site to a neighboring vacancy. In classical transition state theory the jump ratecontains the energy difference between the original equilibrium state and the saddle point (=transition) state. In traditional KMC the saddle point has mostly received rather careless treat-ment, setting it constant or relating it to the type of jumping atom. In the present work, saddlepoint heights were considered explicitly. Taking L12 ordered Ni3Al as an example, jump energyprofiles for various atom environments were calculated ab initio in relaxed configurations ofa 3x3x3 supercell, employing the Nudged Elastic Band method where necessary. From theseresults, effective ’pure’ saddle point heights were extracted. To show the effect on kinetics,simulations of order-order transitions were done with jump probabilities based on these results.When compared to the old assumption of constant saddle point heights, both overall kineticsand detailed jump statistics result considerably changed.

scholarly journals Adsorption and Surface Diffusion of Metals on α-Al2O3 for Advanced Manufacturing Applications

JOM ◽  
2021 ◽  
Vol 73 (4) ◽  
pp. 1062-1070
Author(s):  
Austin Biaggne ◽  
Gregory Noble ◽  
Lan Li
Keyword(s):  
Surface Diffusion ◽  
Density Functional ◽  
Advanced Manufacturing ◽  
Elastic Band ◽  
Adsorption Sites ◽  
Band Method ◽  
Diffusion Paths ◽  
Adsorption Energies ◽  
Manufacturing Applications ◽  
Α Al2o3

AbstractThe adsorption and diffusion of Mo and Nb adatoms on the $$\alpha$$ α -Al2O3 (0001) surface were explored using density functional theory-based methods. Adsorption energies of Mo and Nb adatoms at minima sites on the surface were determined. Mo and Nb adatoms prefer to adsorb to the same locations on the surface, and larger adsorption energies calculated for Nb compared to Mo indicate that Nb adatom-surface interactions are stronger than Mo. Using minima adsorption sites as initial and final locations for surface diffusion, energy barriers for diffusion were calculated using the nudged elastic band method. Overall, Mo and Nb follow roughly the same diffusion paths. The diffusion pre-factors for Mo and Nb are similar; however, Mo diffusion has a lower energy barrier and thus a larger diffusion coefficient compared with Nb. These results provide insight into the role of surface diffusion of Mo and Nb adatoms during advanced manufacturing processes.

Ab Initio Pseudopotential Calculations of Carbon Impurities in SI

1996 ◽  
Vol 438 ◽  
Author(s):  
Jing Zhu ◽  
T. Diaz De La Rubia ◽  
Christian Mailhiot
Keyword(s):  
Binding Energy ◽  
Ab Initio ◽  
Crystalline Silicon ◽  
Carbon Diffusion ◽  
Migration Energy ◽  
Interstitial Carbon ◽  
Enhanced Diffusion ◽  
Carbon Impurities ◽  
Pseudopotential Calculations ◽  
Large Binding Energy

AbstractAb initio planewave pseudopotential method is used to study carbon diffusion and pairing in crystalline silicon. The calculation is performed with a 40 Ry planewave cutoff and 2×2×2 special k-point sampling with a supercell of 64 atoms. It is found that substitutional carbon attracts interstitial Si forming a <001> C interstitial with a large binding energy of 1.45 eV. The interstitial carbon is mobile and can migrate with a migration energy of 0.5 eV. The interstitial carbon can bind further to another substitutional carbon forming a substitutional carbon-interstitutional carbon pair with a binding energy of 1.0 eV. This model is used to understand the effect of high C concentration on the transient enhanced diffusion in Si.

Ab initio calculation of point defect energies and atom migration profiles in varying surroundings in L12-ordered intermetallic compounds

2004 ◽  
Vol 842 ◽  
Author(s):  
Doris Vogtenhuber ◽  
Jana Houserova ◽  
Walter Wolf ◽  
Raimund Podloucky ◽  
Wolfgang Pfeiler ◽  
...  
Keyword(s):  
Ab Initio ◽  
Kinetic Monte Carlo ◽  
Monte Carlo Model ◽  
Elastic Band ◽  
Energy Profiles ◽  
Defect Energies ◽  
Ordered Intermetallic ◽  
Band Method ◽  
Atom Migration ◽  
Ab Initio Approach

ABSTRACTFormation energies of antisite defects and vacancies were derived for the L12-ordered intermetallics Ni3Al, Ni3Ga, Pt3Ga, and Pt3In by a supercell ab initio approach. A thermodynamic treatment of point-like defects was then used for the calculation of temperature-dependent defect properties. Energy profiles for atom jumps in Ni3Al in systematically varied atomic neighborhoods were calculated by statically displacing the jumping atom or by using a nudged elastic band method. It is discussed how a kinetic Monte-Carlo model can be modified so that the jump barrier height reflects the strongest neighborhood influences.

scholarly journals Effects of Mo alloying on stability and diffusion of hydrogen in the Nb16H phase: a first-principles investigation

RSC Advances ◽  
2019 ◽  
Vol 9 (34) ◽  
pp. 19495-19500 ◽  
Author(s):  
Dianhui Wang ◽  
Yang Wu ◽  
Zhenzhen Wan ◽  
Feng Wang ◽  
Zhongmin Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Structural Stability ◽  
First Principles ◽  
Hydrogen Diffusion ◽  
First Principles Calculations ◽  
Elastic Band ◽  
Diffusion Behavior ◽  
Band Method ◽  
And Diffusion ◽  
Diffusion Of Hydrogen

First-principles calculations and climbing-image nudged elastic band method were used to investigate the effects of Mo alloying on the structural stability, mechanical properties, and hydrogen-diffusion behavior of Nb.

Concentration-Dependence of Self-Interstitial and Boron Diffusion in Silicon

2008 ◽  
Vol 1070 ◽  
Author(s):  
Wolfgang Windl
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Ab Initio Calculations ◽  
Fermi Level ◽  
Total Energy ◽  
Ab Initio ◽  
The Self ◽  
Recent Experimental Data ◽  
Boron Diffusion ◽  
Experimental Values

ABSTRACTIn this paper, we discuss the accuracy of ab-initio calculations for self-interstitial and boron dif-fusion in silicon in light of recent experimental data by de Salvador et al. and Bracht et al. Map-ping the experimental data onto the activation energy vs. Fermi level representation commonly used to display ab-initio results, we show that the experimental results are consistent with each other. While the theoretical LDA value for the boron activation energy as a function of the Fermi level agrees well with experiment, we find for the self-interstitial in line with other calculations an underestimation of the experimental values, despite using total-energy corrections.

Ab Initio Pseudopotential Calculations of Carbon Impurities In SI

1996 ◽  
Vol 439 ◽  
Author(s):  
Jing Zhu ◽  
T. Diaz De La Rubia ◽  
Christian Mailhiot
Keyword(s):  
Binding Energy ◽  
Ab Initio ◽  
Crystalline Silicon ◽  
Carbon Diffusion ◽  
Migration Energy ◽  
Interstitial Carbon ◽  
Enhanced Diffusion ◽  
Carbon Impurities ◽  
Pseudopotential Calculations ◽  
Large Binding Energy

AbstractAb initio planewave pseudopotential method is used to study carbon diffusion and pairing in crystalline silicon. The calculation is performed with a 40 Ry planewave cutoff and 2×2×2 special k-point sampling with a supercell of 64 atoms. It is found that substitutional carbon attracts interstitial Si forming a <001> C interstitial with a large binding energy of 1.45 eV. The interstitial carbon is mobile and can migrate with a migration energy of 0.5 eV. The interstitial carbon can bind further to another substitutional carbon forming a substitutional carbon-interstitutional carbon pair with a binding energy of 1.0 eV. This model is used to understand the effect of high C concentration on the transient enhanced diffusion in Si.

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