Fundamental study of nucleation and heteroepitaxial thin film growth using ionized source beam

Ni clusters have been produced using a nozzle source beam. The adiabatically expanded Ni clusters were impact-ionized, accelerated and delivered to carbon substrate for the control of size and distribution. The deposition parameters investigated are the diameter of the adiabatic nozzle, the proportion and energy of the ionized particles in the cluster beam, the substrate temperature, and the deposition time. The use of electron irradiation and acceleration of the source beam has proven to be particularly effective in producing uniform Ni clusters as small as 10A with very narrow size distribution. An Arrhenius plot of substrate temperature versus average cluster diameter revealed that the activation energy due to the beam ionization was 2.5 times higher than the neutral nozzle beam case. Also, the resulting critical shear stress acting on the interface between the cluster and the substrate showed that the critical shear stress of ionized clusters was one order of magnitude higher than that of neutral clusters. These results indicate that the two dimensional cluster growth would be favored by the enhanced coalescence if the neutral clusters are ionized during deposition.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Materials Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Yoo, Myung Cheol

Contributors dc:contributor

• Kim, Kyekyoon

• Engineering, Electronics and Electrical
• Engineering, Metallurgy
• Engineering, Materials Science

Statement dc:rights

• Copyright 1992 Yoo, Myung Cheol

Language dc:language

eng

Identifier

AAI9305744
(UMI)AAI9305744

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/20415