β-Ga₂O₃ For Power Electronic Devices

ASHER, JACOB

doi:10.23889/SUThesis.71340

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β-Ga₂O₃ For Power Electronic Devices / JACOB ASHER

Swansea University Author: JACOB ASHER

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DOI (Published version): 10.23889/SUThesis.71340

Abstract

This thesis explores the development of processes to realise β-Ga2O3-based devices, focusing on etching protocols, dielectric characterisation, and forming ohmic contacts.This work started with developing a photoresist process to enable trench etching for bulk (001) β-Ga2O3 using SiNx hard masks and...

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Published:	Swansea University 2025
Institution:	Swansea University
Degree level:	Doctoral
Degree name:	Ph.D
Supervisor:	Jennings, M.
URI:	https://cronfa.swan.ac.uk/Record/cronfa71340

first_indexed	2026-01-29T13:37:44Z
last_indexed	2026-01-30T06:53:11Z
id	cronfa71340
recordtype	RisThesis
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spelling	2026-01-29T13:52:39.3726131 v2 71340 2026-01-29 β-Ga₂O₃ For Power Electronic Devices 53d34ef4e9e7a6998d2ee248a5a12834 JACOB ASHER JACOB ASHER true false 2026-01-29 This thesis explores the development of processes to realise β-Ga2O3-based devices, focusing on etching protocols, dielectric characterisation, and forming ohmic contacts.This work started with developing a photoresist process to enable trench etching for bulk (001) β-Ga2O3 using SiNx hard masks and dry etching. SiNx was used as the hard mask due to it’s selectivity to β-Ga2O3, and the ease of removal compared to metal masks such as Cr. A photoresist protocol for patterning was developed and tested on Si, α-Al2O3, and β-Ga2O3. These processes are critical for isolating regions in devices like FinFETs and J-FETs, with SiNx demonstrated to be an eﬀective hard mask.The research continued with a study which characterises Al2O3 (ALD) and SiO2 (PECVD) dielectrics on bulk (001) β-Ga2O3 through MIS capacitor fabrication. The eﬀects of prolonged post-metalisation annealing were investigated using CV measurements and the Terman method, this showed a reduction in the hysteresis and interface traps (Dit) after annealing at 200°C. ALD Al2O3 exhibited superior interface quality compared to PECVD SiO2. TEM-EDX analysis revealed potential diﬀusion at the metal-dielectric interface. There was also an apparent decrease in ﬁlm thickness after annealing.The ﬁnal experimental section examines ohmic contacts on β-Ga2O3 using Ti/Al, Ti/Au, Ti/Ag, and Ti/W metalisations. Ti/Au is the most common metal which is used as an ohmic contact, hence deemed to be the most reliable to use as the standard ohmic contact to β-Ga2O3. Ti/Ag had the lowest resistance, however, limited data to agree with this, and so need to be repeated with more reliable experiments.This work lays the foundation for further work to form β-Ga2O3 devices. By investigating processes like etching, dielectric integration, and ohmic contact formation. Finally future work is outlined in the ﬁnal Chapter, includes optimising material interfaces and reﬁning measurement techniques. E-Thesis Swansea University β-Ga2O3, beta-Ga2O3. GaO, Gallium Oxide, characterisation, MOS, MIS, Metal-OxideSemiconductor, Interface trap density, Dit, Terman, CV, Voltage-Capacitance, Ohmiccontacts, CTLM, IV, Current-Voltage, Barrier height, φb, Power electronic devices 17 10 2025 2025-10-17 10.23889/SUThesis.71340 COLLEGE NANME COLLEGE CODE Swansea University Jennings, M. Doctoral Ph.D DTP- UKRI DTP- UKRI 2026-01-29T13:52:39.3726131 2026-01-29T13:16:48.9721827 Faculty of Science and Engineering School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Electronic and Electrical Engineering JACOB ASHER 1 71340__36142__ed5c752e5b364ee8baf90efe5d5612a1.pdf 2026_Asher_J.final.71340.pdf 2026-01-29T13:49:20.8235634 Output 24355840 application/pdf E-Thesis – open access true Copyright: the author, Jacob Jared Asher, 2026 true eng
title	β-Ga₂O₃ For Power Electronic Devices
spellingShingle	β-Ga₂O₃ For Power Electronic Devices JACOB ASHER
title_short	β-Ga₂O₃ For Power Electronic Devices
title_full	β-Ga₂O₃ For Power Electronic Devices
title_fullStr	β-Ga₂O₃ For Power Electronic Devices
title_full_unstemmed	β-Ga₂O₃ For Power Electronic Devices
title_sort	β-Ga₂O₃ For Power Electronic Devices
author_id_str_mv	53d34ef4e9e7a6998d2ee248a5a12834
author_id_fullname_str_mv	53d34ef4e9e7a6998d2ee248a5a12834_***_JACOB ASHER
author	JACOB ASHER
author2	JACOB ASHER
format	E-Thesis
publishDate	2025
institution	Swansea University
doi_str_mv	10.23889/SUThesis.71340
college_str	Faculty of Science and Engineering
hierarchytype
hierarchy_top_id	facultyofscienceandengineering
hierarchy_top_title	Faculty of Science and Engineering
hierarchy_parent_id	facultyofscienceandengineering
hierarchy_parent_title	Faculty of Science and Engineering
department_str	School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Electronic and Electrical Engineering{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Electronic and Electrical Engineering
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description	This thesis explores the development of processes to realise β-Ga2O3-based devices, focusing on etching protocols, dielectric characterisation, and forming ohmic contacts.This work started with developing a photoresist process to enable trench etching for bulk (001) β-Ga2O3 using SiNx hard masks and dry etching. SiNx was used as the hard mask due to it’s selectivity to β-Ga2O3, and the ease of removal compared to metal masks such as Cr. A photoresist protocol for patterning was developed and tested on Si, α-Al2O3, and β-Ga2O3. These processes are critical for isolating regions in devices like FinFETs and J-FETs, with SiNx demonstrated to be an eﬀective hard mask.The research continued with a study which characterises Al2O3 (ALD) and SiO2 (PECVD) dielectrics on bulk (001) β-Ga2O3 through MIS capacitor fabrication. The eﬀects of prolonged post-metalisation annealing were investigated using CV measurements and the Terman method, this showed a reduction in the hysteresis and interface traps (Dit) after annealing at 200°C. ALD Al2O3 exhibited superior interface quality compared to PECVD SiO2. TEM-EDX analysis revealed potential diﬀusion at the metal-dielectric interface. There was also an apparent decrease in ﬁlm thickness after annealing.The ﬁnal experimental section examines ohmic contacts on β-Ga2O3 using Ti/Al, Ti/Au, Ti/Ag, and Ti/W metalisations. Ti/Au is the most common metal which is used as an ohmic contact, hence deemed to be the most reliable to use as the standard ohmic contact to β-Ga2O3. Ti/Ag had the lowest resistance, however, limited data to agree with this, and so need to be repeated with more reliable experiments.This work lays the foundation for further work to form β-Ga2O3 devices. By investigating processes like etching, dielectric integration, and ohmic contact formation. Finally future work is outlined in the ﬁnal Chapter, includes optimising material interfaces and reﬁning measurement techniques.
published_date	2025-10-17T05:35:05Z
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score	11.096295

β-Ga₂O₃ For Power Electronic Devices / JACOB ASHER

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