Quantitative Electron Microscopy Studies of Silicon Germanium/silicon(001)
Henstrom, William Lee
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/80687
Description
Title
Quantitative Electron Microscopy Studies of Silicon Germanium/silicon(001)
Author(s)
Henstrom, William Lee
Issue Date
2000
Doctoral Committee Chair(s)
Gibson, J. Murray
Department of Study
Physics
Discipline
Physics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Physics, Condensed Matter
Language
eng
Abstract
Over the last decade, much progress has been made in understanding the thermodynamic and kinetic properties of self-assembled quantum dot structures. These structures form as a result of the strain energy in mismatched epitaxial systems. Ge/Si(001) has been investigated for its potential importance technologically, as well as serving as a model system. However, it has been difficult to obtain data on how the strain in these islands effects the island's thermodynamic properties and kinetic evolution. In this work, we investigate the thermodynamics and kinetics of the Ge/Si(001) system. We have applied the new Abrupt Displacement Approximation using transmission electron microscopy (TEM) to measure the average island strain, and have coupled this with the Suppressed Diffraction condition to measure the size and the shape of the islands. By these techniques, as well as some more traditional TEM methods, we directly show the energetic pathway of the island shape reverse transition. We show how the thermodynamic island diameter is ∝1/32r , where 3r is the strain reduction in an island. We also use these methods to understand the kinetic properties of the island formation and growth. We show that Ge does segregate out of Si1-xGe x alloy films to create islands with higher Ge concentration than the deposited film. We also show that the coarsening of the island diameter growth that occurs during a 650°C anneal obeys a power law which suggests that adatoms detach from the perimeter of the islands contact line with the substrate and diffuse via surface diffusion between islands.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
