Improving imaging performance in planar superlenses

Type of content
Theses / Dissertations
Publisher's DOI/URI
Thesis discipline
Electrical Engineering
Degree name
Doctor of Philosophy
Publisher
University of Canterbury. Department of Electrical and Computer Engineering
Journal Title
Journal ISSN
Volume Title
Language
Date
2011
Authors
Schøler, Mikkel
Abstract

The aim of this project was to improve the imaging performance of planar superlenses for evanescent near-field lithography. An experimental investigation of the performance of superlenses with reduced surface roughness was proposed. Such an investigation poses significant requirements in regards to process control in thin film deposition of silver onto dielectric substrates. Thin film deposition of silver films, onto silicon dioxide substrates, achieved films with root mean square surface roughness as low as 0.8 nm. While these experiments provided good understanding of the deposition process, significant variability of the surface roughness parameter remained an issue. The diffculty of achieving consistent control of surface roughness led to a finite element method simulation study where this parameter could be readily controlled. An improved understanding of how surface roughness affects superlens imaging performance was obtained from the results of this investigation. Furthermore, it was shown that in order to conduct an experimental investigation to verify the simulation results, it would be necessary to improve the imaging capability of super-resolution lithography protocols to achieve 3σ line edge roughness (LER) of <20 nm. Resist-scheme optimisation was identied as an important factor in this regard. Thus, a novel calixarene-based photoresist was formulated and characterised. The resist demonstrated superior imaging capabilities through interference lithography and evanescent near-field optical lithography, capable of resolving 250-nm period half-pitch line gratings with 3σ LER below 10 nm. The development of this novel photoresist will enable future lithographical investigations to be conducted with improved resolution and imaging fidelity.

Description
Citation
Keywords
nano, photonics, optics, photo, lithography, resist, superlens, negative refraction
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Rights
Copyright Mikkel Schøler