Plasma technology for the production of superconducting thin films in accelerator applications

Walk, Felix (2023) Plasma technology for the production of superconducting thin films in accelerator applications. PhD thesis, University of Liverpool.

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Abstract

Energetic ion bombardment in plasma deposition is a key feature in tailoring specific microstructures, crystallographic orientations and phases of thin films. The high-power impulse magnetron sputtering (HiPIMS) technique is considered an ionised physical vapor deposition (PVD) process, where a substantial amount of metal ions contribute to the growth process. It has already been successfully used to produce superconducting radio frequency (SRF) cavities, but ion energy control via substrate biasing is not always viable. The newly emerged technique of bipolar HiPIMS, where a reverse positive voltage follows the negative HiPIMS pulse, is overcoming this issue for grounded substrates. The aim of this thesis is to take a plasma diagnostic approach to the deposition of superconducting thin films. The bipolar HiPIMS discharge is analysed by means of Langmuir probe and retarding field energy analyser (RFEA) measurements and produced samples are characterised via scanning electron microscopy (SEM), with electron backscatter diffraction (EBSD) analysis and tested on their superconducting properties via a vibrating sample magnetometer (VSM).

Item Type:	Thesis (PhD)
Uncontrolled Keywords:	HiPIMS, Bipolar HiPIMS, Niobium, Langmuir probe, RFEA, EBSD
Divisions:	Faculty of Science and Engineering > School of Electrical Engineering, Electronics and Computer Science
Depositing User:	Symplectic Admin
Date Deposited:	20 Jul 2023 11:42
Last Modified:	20 Jul 2023 11:42
DOI:	10.17638/03168257
Supervisors:	Bradley, James
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3168257