Computer simulation of cluster ion impacts on a solid surface

Z. Insepov, I. Yamada

Research output: Contribution to journalConference articlepeer-review

Abstract

The sputtering probabilities for normal and oblique cluster ion impacts were calculated by the use of two-dimensional molecular dynamics (MD) calculations. These simulations have revealed the angular dependence of ejecting surface atoms on the cluster incidence angle. The ejecting flux has a symmetrical form with an essential lateral component in the case of normal cluster incidence. For an oblique cluster indidence we found a sharp asymmetry of sputtering orientation. We obtained that the ejecting flux consists of three components: a) fast flying atoms with the velocities higher than the cluster velocity ν approx. 2.3ν0, b) approximately self-similar component with ν ≈ ν0, and, finally, c) slowly moving tail with ν approx. 0.2ν0, where ν0 is the cluster velocity. According to our MD results we developed a new model of surface modification phenomena which consists of the Langevin Dynamics based on the Kardar-Parisi-Zhang equation, combined with a Monte-Carlo procedure for crater formation at normal and oblique cluster impacts. We obtained that for a symmetrical crater shape with a size in the order of 20 angstrom, a significant smoothing occurs after irradiation by approx. 103 cluster impacts which has been supported by experiment at dose of approx. 1014 ion/cm2. The rate of the smoothing process can be significantly accelerated if the lateral sputtering phenomenon is taken into account. Simulation of oblique cluster impact on a surface at a grazing angle of 30° by constructing of asymmetric crater shape gives an opposite result: the surface roughness increases. The latter obtaining qualitatively agrees with the experiment.

Original languageEnglish
Pages (from-to)591-597
Number of pages7
JournalMaterials Research Society Symposium - Proceedings
Volume408
Publication statusPublished - Dec 1 1996
Externally publishedYes
EventProceedings of the 1996 MRS Fall Symposium - Boston, MA, USA
Duration: Nov 27 1995Dec 1 1995

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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