University of Illinois Urbana-Champaign

Surface diffusion processes critical to metallic film nucleation and growth: An atomic view

Liu, Chun-Li

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https://hdl.handle.net/2142/23123

Description

Title
Surface diffusion processes critical to metallic film nucleation and growth: An atomic view
Author(s)
Liu, Chun-Li
Issue Date
1993
Doctoral Committee Chair(s)
Adams, James B.
Department of Study
  • Engineering, Chemical
  • Engineering, Metallurgy
  • Engineering, Materials Science
Discipline
  • Engineering, Chemical
  • Engineering, Metallurgy
  • Engineering, Materials Science
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • Engineering, Chemical
  • Engineering, Metallurgy
  • Engineering, Materials Science
Language
eng
Abstract
"Extensive computer simulations have been performed to study diffusion processes critical to nucleation and growth of metallic thin films. Diffusion behavior of (1) single adatoms on a flat surface, (2) single adatoms near and at steps on a vicinal surface, and (3) small adatom cluster migration on terraces and (4) single vacancies on a flat surface has been investigated. Many important results have been found. For instance, (i) For adatom diffusion near steps on Ni(111) there exists a ""forbidden"" region near steps. The adatoms have to overcome a slightly higher energy barrier to get into the ""forbidden"" region. This is consistent with the latest FIM experiments for Ir adatom diffusion near Ir clusters on Ir(111). (ii) Exchange diffusion at descending steps of type B on Ni(111) was found to be energetically favored and is the dominant mechanism for incorporation of adatoms over descending steps into the step ledges. This is consistent with earlier FIM experiments for W adatom diffusion at Ir cluster steps on Ir(111). (iii) Diffusion of adatoms along the step ledges can be either enhanced, as on Ni(100), or hindered, as on Ni(111). (iv) For the first time an exchange mechanism was found to be favored at descending steps on Ni(110) and (100). (v) The energy barriers for vacancy diffusion on five fcc surfaces were found to be higher than those for single adatom diffusion. (vi) Small clusters migrate in different fashions on different surfaces: on Ni(100) they move through a series of individual jumps of single atoms in the clusters; on Ni(111), for the first time they were found to migrate by concerted jumps of all the atoms in the clusters. The trend in the energy barriers on both surfaces was found to be consistent with available FIM experimental data."
Type of Resource
text
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http://hdl.handle.net/2142/23123
Copyright and License Information
Copyright 1993 Liu, Chun-Li

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