Simulation of nanocolumn formation in a plasma environment

Abstract

Recent experiments and kinetic Monte Carlo (KMC) simulations [H. Greve et al., Appl. Phys. Lett. 88, 123103 (2006), L. Rosenthal et al., J. Appl. Phys. 114, 044305 (2013] demonstrated that physical vapor co-deposition of a metal alloy (Fe-Ni-Co) and a polymer (Teflon AF) is a suitable method to grow magnetic nanocolumns in a self-organized one-step process. While only thermal sources have been used so far, in this work, we analyze the feasibility of this process for the case of a sputtering source. For that purpose, we extend our previous simulation model by including a process that takes into account the influence of ions impinging on the substrate. The simulation results predict that metal nanocolumn formation should be possible. Furthermore, we show that the effect of ions that create trapping sites for the metal particles is to increase the number of nanocolumns.

Molecular dynamics simulation of gold cluster growth during sputter deposition

“…Another potential application of the simulation scheme is the simulation of the co-deposition processes of, for example, metal and polymer, which could be realized by implementing a continuous shift of the surface. Similar implementations have already been applied in the framework of the aforementioned kinetic Monte Carlo simulations [16,29].…”

“…The simulation model takes advantage of some ideas from previous kinetic Monte Carlo models that have been successfully applied to simulate similar systems [16,29]. These ideas comprise the representation of the substrate as a continuum, which causes random walks of the metal particles, as well as the implementation of simplistic processes that take into account the desorption of atoms on the surface and the creation of defects at the surface by the impingement of highly energetic particles from the plasma.…”

“…Instead the diffusive motion of the metal atoms on the surface is driven by fluctuating and dissipative forces. This is much simpler than atomistic or coarsegrained surface models, but it has been shown in previous kinetic Monte Carlo (KMC) studies [16,17,29,36,37] that the diffusive motion of the metal atoms can be appropriately described by employing a continuum model for the polymer. This treatment is physically motivated by the facts that the assembly of polymer chains is very disordered and the interaction between metal and polymer is typically very weak [38].…”

“…So far, however, we are not aware of any computational studies of thin-film growth by sputter deposition which resolve not only the atomic structure of the clusters, but also take into account the influence of the polymer and the plasma background. Although kinetic Monte Carlo simulations have proved to be appropriate for the description of similar systems, they are usually restricted to cases with simple cluster geometries that allow one to neglect the motion of individual atoms such that clusters can be approximated by simple geometrical objects, e. g., spheres or columnar structures [16,28,29]. In this work, we go beyond these limitations by introducing an atomic scale molecular dynamics (MD) simulation scheme for the motion of sputter-deposited gold particles onto a polymeric surface.…”

Molecular dynamics simulation of Ag–Cu cluster growth on a thin polymer film

“…As such a description is very time consuming and would, hence, strongly limit the scope of the simulations, we preferred to describe the polymer as a continuum acting on the metal atoms via statistical forces. The validity of this approach has been confirmed not only in very similar previous MD simulations for gold (instead of silver and copper) atoms and by comparison with experiments but also in kinetic Monte Carlo simulations for the formation of metal–polymer nanocomposites , , …”