טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentHaimovich Karin
SubjectInvestigation of Surface Phenomena on Template Stripped
Thin Films of Gold
DepartmentDepartment of Materials Science and Engineering
Supervisor Professor Boaz Pokroy


Abstract

Atomic stepped surfaces which exhibit well-ordered, periodic arrays of atomic steps can be formed by several methods. These surfaces are often referred to in the literature as “vicinal surfaces” and are widely applicative in microelectronics, catalytic processes and as templates for the fabrication of nanostructures such as nanowires, quantum dots, C60, self-assembled monolayers and many more. The traditional, expensive and time-consuming, method for producing vicinal surfaces utilizes single crystals of metals or semiconductors which are cut in a low angle that deviates from a low surface-energy plane, followed by ion bombardment and annealing under ultra-high vacuum conditions. Recently, a new method for producing vicinal-like surfaces was developed in our lab. It involves annealing of polycrystalline films at atmospheric environment followed by template stripping of the film, to expose its atomic stepped interface. In this thesis, we investigate the evolution of vicinal-like surfaces at the interface of thin films of gold, from the point of their formation during various high-temperature annealing treatments. By an in-situ high-resolution TEM examination, we show the formation of atomic steps at the ultra-flat interface of the gold film and the silicon dioxide substrate. 

We present a comprehensive characterization of the vicinal-like surfaces at high-temperatures and their stability up to 0.85 of melting-temperature of gold. Upon annealing at high-temperatures, the thin gold films transform into discontinuous layers of crystals with facets at the crystals surface and an atomic steps structure at their interface with the substrate. By stripping the faceted crystals, we show that curved crater-shaped separation is formed at the interface to reduce the particle free-surface-energy.

Additionally, we present a crystallographic study of the Au/SiO2 system and show that a thin gold film evaporated on an amorphous substrate has an inherent misorientation around a mean angle which deviates from the assumed energetically preferred (111) planes.