New chemistries and applications in molecular layer deposition

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Recent advancements in nanotechnologies have highlighted the need for thin film deposition capabilities that allow for fine thickness and compositional control. One technique that could help meet these needs is molecular layer deposition (MLD). MLD is a vapor-to-surface organic deposition method that utilizes sequential, self-limiting surface reactions, whereby thin film polymers can be grown. Since its inception, there has been significant progress in MLD synthesis capability, but certain challenges remain. Due to its vapor-phase nature, MLD is unable to utilize solvents and catalysts available to solution phase chemistry. This constraint has limited the variety of polymers that can be grown by MLD, including those formed by carbon-carbon bond synthesis. Another challenge for MLD is to enable area selective (AS) deposition, a process of significant interest in the semiconductor industry because of its potential to reduce fabrication processing steps and facilitate the scale-down of device feature sizes. The first portion of this work discusses a technique allowing for enhanced selectivity in AS-MLD. To achieve these highly selective depositions, a self-assembled monolayer (SAM) layer is used to act as a resist towards MLD. A chemical lift-off step is also employed, which is shown to significantly increase the overall selectivity of the AS-MLD process. Next, a new method for MLD of a silicon oxycarbide (SiOC) material is introduced. SiOC films are typically made with highly oxidizing reactants at elevated temperatures, causing film degradation during the deposition. The new MLD process, however, utilizes mild reactants at room temperature, thereby eliminating degradation problems, resulting in well defined SiOC films. The SiOC films crosslink during the deposition forming a robust film with exceptional thermal stability. The films show a low dielectric (k) constant, supporting their potential use in semiconductor devices where thermally resistant coatings with low-k properties are needed. Lastly, the development of a new MLD polymer is introduced. By utilizing UV light for radical polymerization, direct formation of carbon-carbon bonds is enabled in a photoactivated MLD (pMLD) synthesis. An alternating hydrocarbon-fluorocarbon copolymer, grown via pMLD using iodo-ene coupling, polymerizes by new carbon-carbon bond formation. The fluoropolymer exhibits high thermal stability and chemical resistance as well as the ability to be patterned using a photomask. The pMLD film also shows the ability to be used as a resist for selective deposition. The continued development of thin film techniques such as MLD is essential for progress to be made in nanoscale technologies and could have significant impact towards increasing energy efficiency, providing clean air and water, and improving healthcare. The focus of this work, therefore, is to advance the capabilities of MLD, allowing for new materials and applications.


Type of resource text
Form electronic resource; remote; computer; online resource
Extent 1 online resource.
Place California
Place [Stanford, California]
Publisher [Stanford University]
Copyright date 2019; ©2019
Publication date 2019; 2019
Issuance monographic
Language English


Author Closser, Richard Gene
Degree supervisor Bent, Stacey
Thesis advisor Bent, Stacey
Thesis advisor Chidsey, Christopher E. D. (Christopher Elisha Dunn)
Thesis advisor Waymouth, Robert M
Degree committee member Chidsey, Christopher E. D. (Christopher Elisha Dunn)
Degree committee member Waymouth, Robert M
Associated with Stanford University, Department of Chemistry.


Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Richard G. Closser.
Note Submitted to the Department of Chemistry.
Thesis Thesis Ph.D. Stanford University 2019.
Location electronic resource

Access conditions

© 2019 by Richard Gene Closser
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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