Date of Award

5-31-2016

Document Type

Campus Access Thesis

Degree Name

Master of Science (MS)

Department

Physics, Applied

First Advisor

Matthew Bell

Second Advisor

Stephen Arnason

Third Advisor

Chandra Yelleswarapu

Abstract

In this thesis we investigate the use of titanium nitride (TiN) thin films for use in superconducting circuits. These circuits benefit from having a material that has a high resistivity, high superconducting transition temperature (TC), low loss at microwave frequencies, and a high kinetic inductance. TiN is sputter deposited 70nm thick onto silicon and tested with a four point probe both at room temperature and as low as 0.5K to find the critical temperature and the resistivity. Superconducting microwave resonators were fabricated using photolithography and a reactive ion etch as a means of determining the losses of TiN wires in an actual circuit. The microwave losses of the film were measured at 20mK and were several orders of magnitude higher than expected. The higher losses can be explained by the design of the resonators. The films were shown to be superconducting with a tunable TC but the resonators had higher losses than expected. These tests show the viability of TiN thin films in superconducting circuits. Future work on reducing the feature size of potential circuits as well as working to make more complex circuits such as hybrids with Al that can create Josephson junctions are important steps towards creating some of the lowest loss superconducting circuits.

Comments

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