Study of Oxygen Diffusion and Clustering in Silicon Using an Empirical Interatomic Potential

1995 ◽  
Vol 378 ◽  
Author(s):  
Z. Jiang ◽  
R. A. Brown
Keyword(s):  
Interatomic Potential ◽  
Crystalline Silicon ◽  
Diffusion Path ◽  
Rate Theory ◽  
Free Energies ◽  
Silicon Crystals ◽  
Oxygen Precipitation ◽  
Dynamics Simulations ◽  
Small Clusters ◽  
Oxygen Atoms

AbstractThe diffusion path and diffusivity of oxygen in crystalline silicon are computed using an empirical interatomic potential which was recently developed [1] for modelling the interactions between oxygen and silicon atoms. The diffusion path is determined by constrained energy minimization, and the diffusivity is computed using jump rate theory. The calculated diffusivity D=0.025 exp(-2.43eV/kBT) cm2/sec is in excellent agreement with experimental data. The same interatomic potential also is used to study the formation of small clusters of oxygen atoms in silicon. The structures of these clusters are found by NPT molecular dynamics simulations, and their free energies are calculated by thermodynamic integration. These free energies are used to predict the temperature dependence of the equilibrium partitioning of oxygen atoms into clusters of different sizes. The calculations show that, for given total oxygen concentration, most oxygen atoms are in clusters at temperature below 1300K, and that the average cluster size increases with decreasing temperature. These results are in qualitative agreement with the effects of thermal annealing on oxygen precipitation in silicon crystals.

scholarly journals Tight-Binding Molecular Dynamics Simulations on Point Defects Diffusion and Interactions in Crystalline Silicon

1995 ◽  
Vol 396 ◽  
Author(s):  
M. tang ◽  
L. colombo ◽  
T. Diaz De La Rubia
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Point Defects ◽  
Crystalline Silicon ◽  
Tight Binding ◽  
Diffusion Path ◽  
Binding Energies ◽  
Defect Clusters ◽  
Dynamics Simulations

AbstractTight-binding molecular dynamics (TBMD) simulations are performed (i) to evaluate the formation and binding energies of point defects and defect clusters, (ii) to compute the diffusivity of self-interstitial and vacancy in crystalline silicon, and (iii) to characterize the diffusion path and mechanism at the atomistic level. In addition, the interaction between individual defects and their clustering is investigated.

Computation of the Onset of Point Defect Aggregation in Crystalline Silicon Using an Empirical Interatomic Potential

1995 ◽  
Vol 378 ◽  
Author(s):  
T. Sinno ◽  
R.A. Brown
Keyword(s):  
Point Defects ◽  
Interatomic Potential ◽  
Driving Forces ◽  
Crystalline Silicon ◽  
Single Point ◽  
Binding Energies ◽  
Single Vacancy ◽  
Single Defect ◽  
Equilibrium Configurations ◽  
Dynamics Simulations

AbstractThe Stillinger-Weber interatomic potential is used in molecular dynamics simulations to investigate the equilibrium, transport and aggregation properties of self-interstitials and vacancies in crystalline silicon at temperatures ranging from 500K to the melting point. The simulations predict equilibrium configurations of a < 110 > dumbbell for the single self-interstitial and an inwardly relaxed structure for the single vacancy. Both single-defect structures exhibit significant derealization at high temperatures resulting in strongly temperature dependent entropies of formation, as suggested by diffusion experiments. Diffusion coefficients and mechanisms for the single defects are predicted as a function of temperature. The results for the single point defects are discussed in the context of the existing literature values. Aggregation of two point defects is investigated by the computation of binding energies and entropies for these structures. Interstitials exhibit significant aggregation driving forces across the entire temperature range under simulation conditions, while vacancies aggregate less readily.

Data-Driven Many-Body Models with Chemical Accuracy for CH4/H2O Mixtures

2020 ◽  
Author(s):  
Marc Riera ◽  
Alan Hirales ◽  
Raja Ghosh ◽  
Francesco Paesani
Keyword(s):  
Liquid Phase ◽  
Quantitative Description ◽  
Liquid Mixtures ◽  
Many Body ◽  
Energy Functions ◽  
Potential Energy Functions ◽  
Dynamics Simulations ◽  
Body Potential ◽  
Small Clusters ◽  
Many Body Interactions

<div> <div> <div> <p>Many-body potential energy functions (PEFs) based on the TTM-nrg and MB-nrg theoretical/computational frameworks are developed from coupled cluster reference data for neat methane and mixed methane/water systems. It is shown that that the MB-nrg PEFs achieve subchemical accuracy in the representation of individual many-body effects in small clusters and enables predictive simulations from the gas to the liquid phase. Analysis of structural properties calculated from molecular dynamics simulations of liquid methane and methane/water mixtures using both TTM-nrg and MB-nrg PEFs indicates that, while accounting for polarization effects is important for a correct description of many-body interactions in the liquid phase, an accurate representation of short-range interactions, as provided by the MB-nrg PEFs, is necessary for a quantitative description of the local solvation structure in liquid mixtures. </p> </div> </div> </div>

scholarly journals Development of a New Sr-O Parameterization to Describe the Influence of SrO on Iron-Phosphate Glass Structural Properties Using Molecular Dynamics Simulations

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4326
Author(s):  
Pawel Goj ◽  
Aleksandra Wajda ◽  
Pawel Stoch
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Interatomic Potential ◽  
Glass Structure ◽  
Ion Pairs ◽  
Glass Network ◽  
Iron Phosphate ◽  
Phosphate Glasses ◽  
Potential Applications ◽  
Dynamics Simulations

Iron-phosphate glasses, due to their properties, have many potential applications. One of the most promising seems to be nuclear waste immobilization. Radioactive 90Sr isotope is the main short-lived product of fission and, due to its high solubility, it can enter groundwater and pose a threat to the environment. On the other hand, Sr is an important element in hard tissue metabolic processes, and phosphate glasses containing Sr are considered bioactive. This study investigated the effect of SrO addition on a glass structure of nominal 30Fe2O3-70P2O5 chemical composition using classical molecular dynamics simulations. To describe the interaction between Sr-O ion pairs, new interatomic potential parameters of the Buckingham-type were developed and tested for crystalline compounds. The short-range structure of the simulated glasses is presented and is in agreement with previous experimental and theoretical studies. The simulations showed that an increase in SrO content in the glass led to phosphate network depolymerization. Analysis demonstrated that the non-network oxygen did not take part in the phosphate network depolymerization. Furthermore, strontium aggregation in the glass structure was observed to lead to the non-homogeneity of the glass network. It was demonstrated that Sr ions prefer to locate near to Fe(II), which may induce crystallization of strontium phosphates with divalent iron.

Oxygen Precipitation in Conventional and Nitrogen Co-Doped Heavily Arsenic-Doped Czochralski Silicon Crystals: Oswald Ripening

2009 ◽  
Vol 156-158 ◽  
pp. 275-278
Author(s):  
Xiang Yang Ma ◽  
Yan Feng ◽  
Yu Heng Zeng ◽  
De Ren Yang
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Czochralski Silicon ◽  
Silicon Crystals ◽  
Oxygen Precipitation ◽  
High Temperature Anneal ◽  
Oxygen Precipitates ◽  
Co Doped ◽  
Oswald Ripening

Oxygen precipitation (OP) behaviors in conventional and nitrogen co-doped heavily arsenic-doped Czocharalski silicon crystals subjected to low-high two-step anneals of 650 oC/8 h + 1000 oC/4-256 h have been comparatively investigated. Due to the nitrogen enhanced nucleation of OP during the low temperature anneal, much higher density of oxygen precipitates generated in the nitrogen co-doped specimens. With the extension of high temperature anneal, Oswald ripening of OP in the nitrogen co-doped specimens preceded that in the conventional ones. Moreover, due to the Oswald ripening effect, the oxygen precipitates in the conventional specimens became larger with a wider range of sizes. While, the sizes of oxygen precipitates in the nitrogen co-doped specimens distributed in a much narrower range with respect to the conventional ones.

Oxygen precipitation behavior in heavily arsenic doped silicon crystals

2017 ◽  
Vol 457 ◽  
pp. 325-330 ◽  
Author(s):  
Stephan Haringer ◽  
Daniela Gambaro ◽  
Maria Porrini
Keyword(s):  
Precipitation Behavior ◽  
Silicon Crystals ◽  
Oxygen Precipitation ◽  
Doped Silicon
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