Optimization of large amorphous silicon and silica structures for molecular dynamics simulations of energetic impacts

Samela, Juha; Norris, Scott A.; Nordlund, K.; Aziz, Michael J.

doi:10.1016/j.nimb.2010.11.017

Cited by 8 publications

(5 citation statements)

References 19 publications

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“…Our MD simulation environment consists of an amorphous, 20×20×10 nm 3 Si target consisting of 219,488 atoms, with slab boundary conditions (free boundary in the incoming ion direction, and periodic boundaries in the other two lateral directions) 30 . The target itself was created using the Wooten/Winer/Weaire method 31 .…”

Section: Methodsmentioning

confidence: 99%

Molecular dynamics of single-particle impacts predicts phase diagrams for large scale pattern formation

et al. 2011

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Energetic particle irradiation can cause surface ultra-smoothening, self-organized nanoscale pattern formation or degradation of the structural integrity of nuclear reactor components. A fundamental understanding of the mechanisms governing the selection among these outcomes has been elusive. Here we predict the mechanism governing the transition from pattern formation to flatness using only parameter-free molecular dynamics simulations of single-ion impacts as input into a multiscale analysis, obtaining good agreement with experiment. our results overturn the paradigm attributing these phenomena to the removal of target atoms via sputter erosion: the mechanism dominating both stability and instability is the impact-induced redistribution of target atoms that are not sputtered away, with erosive effects being essentially irrelevant. We discuss the potential implications for the formation of a mysterious nanoscale topography, leading to surface degradation, of tungsten plasma-facing fusion reactor walls. Consideration of impact-induced redistribution processes may lead to a new design criterion for stability under irradiation.

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Section: Methodsmentioning

confidence: 99%

Molecular dynamics of single-particle impacts predicts phase diagrams for large scale pattern formation

et al. 2011

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“…Because the additional terms describe the effect of surface curvature on the purely-erosive zeroth moment M (0) , adoption has tended to depend on the energy studied and simulation method used. Studies at higher energies using the BCA now regularly include the terms, 92,[116][117][118][119] because they seem to contribute meaningfully to the coefficients c 11 (h) and c 22 (h) at those energies, and some BCA codes readily allow the simulation of ion impacts on curved targets. On the other hand, studies at lower energies using MD may still omit the terms, 111,115,116 because of the complexity of creating relaxed amorphous targets with varying curvatures, and because erosive effects are not particularly strong at such energies.…”

Section: B Parameter Evaluationmentioning

confidence: 99%

Ion-induced nanopatterning of silicon: Toward a predictive model

Norris

Aziz

2019

Applied Physics Reviews

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We review recent progress toward the development of predictive models of ion-induced pattern formation on roomtemperature silicon, with a particular emphasis on efforts to eliminate fit parameters in the linear regime by means of experimental measurements or atomistic simulations. Analytical approaches considered include "mechanistic" models of the impactinduced collision cascade, the Crater Function Framework, and continuum treatments of ion-induced stress and viscous flow. Parameter evaluation methods include molecular dynamics and binary collision approximation simulations, as well as wafer curvature measurements and grazing incidence small-angle x-ray scattering. Mathematical detail is provided in the context of key results from pattern formation theory, which are also briefly summarized.

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“…Although in principle these moments describe the topography at small scales, they can be incorporated into continuum models to describe the surface morphology at much larger scales. This in turn allows to provide estimates for many of the parameters of these large-scale formulations [188,[130][131][132][133]189]. Hence, this formalism represents a multiscale approach to connect atomistic MD simulations to the continuum models which will be reviewed in the next section.…”

Section: From MD To Continuum Models (Crater Function Approach)mentioning

confidence: 99%