Ion Irradiation Induced Roughening and Smoothing of Metal Films on Dielectric Substrates
Hu, Xiaoyuan
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/2142/82720
Description
Title
Ion Irradiation Induced Roughening and Smoothing of Metal Films on Dielectric Substrates
Author(s)
Hu, Xiaoyuan
Issue Date
2002
Doctoral Committee Chair(s)
Averback, Robert S.
Cahill, David G.
Department of Study
Materials Science and Engineering
Discipline
Materials Science and Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Engineering, Materials Science
Language
eng
Abstract
This study investigates the morphology evolution of ultrathin Pt films on dielectric substrates produced by heavy ion bombardment. The films roughen and form nanopatterns which coarsen in a certain dose range. The microstructure evolution is characterized using AFM, SEM and RBS. The results are explained using a novel irradiation induced dewetting mechanism involving local melting and viscous flow. The temperature-independent dewetting process scales with energy deposition density (J/cm2). Fissures in the initial films are identified as nuclei of dry patches for the dewetting process. Growth kinetics of the dry patches is followed using in situ TEM. Due to line tension in the curved contact lines during local melting, irradiation induced dewetting occurs much slower than dewetting under homogeneous heating. At high irradiation doses, nanopattern disappear to form nanoparticles with decreased surface roughness. The particles embed into the substrates, leading to the smoothing of the surface. The embedding kinetics is studied using cross-sectional TEM. An analytical model based on capillary driving force and viscous flow of the substrate is built to quantitatively explain the experimental results. The irradiation-induced viscosity of SiO2 is extracted to be ∼0.9 x 1023 Pa ion cm-2, consistent with previous measurements using stress relaxation.
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.
