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Download fileMolecular dynamics simulations of the growth of Ge on Si
journal contribution
posted on 2020-02-25, 09:38 authored by Ying Zhou, Adam Lloyd, Roger Smith, Kirill A. Lozovoy, Alexander V. Voitsekhovskii, Andrey P. KokhanenkoThe initial stages of the growth of germanium on the dimer reconstructed Si(100) surface is modelled using molecular dynamics (MD). Pyramidal island structures are observed to form despite MD being carried out at a deposition rate faster than experiment. By an examination of transitions that can occur from intermediate structures that form in the MD simulations, growth mechanisms can be identified. The initial wetting occurs as a result of Ge atoms diffusing into the trenches between the dimer rows. This results in Ge-Ge or Ge-Si dimer chains growing in rows perpendicular to the original Si-Si dimer rows on the surface. It is shown how strained Ge pyramids with square bases can form by diffusing atoms joining together adjacent dimer rows. From these initial square-based structures, complex concerted motions are observed in which atoms in lower layers ‘climb up’ to higher layers. Similar structures grown in the pure Si case exhibit much higher energy barriers for the ‘climbing up’ process indicating that the effect of strain is to reduce the energy barriers for pyramid formation. In addition to the investigation of atomistic growth processes, surface energy effects are also examined, which show that a germanium-covered Si(100) surface containing shallow-angled pyramids is energetically more favourable than that grown as a flat monolayer.
Funding
Royal Society of London
History
School
- Science
Department
- Mathematical Sciences
Published in
Surface ScienceVolume
696Publisher
ElsevierVersion
- AM (Accepted Manuscript)
Rights holder
© ElsevierPublisher statement
This paper was accepted for publication in the journal Surface Science and the definitive published version is available at https://doi.org/10.1016/j.susc.2020.121594.Acceptance date
2020-02-21Publication date
2020-02-27Copyright date
2020ISSN
0039-6028Publisher version
Language
- en