Morphological and electrical comparison of Ti and Ta based ohmic contacts for AlGaN/GaN-on-SiC HFETs

Pooth, A., Bergsten, J., Rorsman, N., Hirshy, Hassan ORCID: https://orcid.org/0000-0003-0281-3681, Perks, Richard ORCID: https://orcid.org/0000-0003-0873-0537, Tasker, Paul ORCID: https://orcid.org/0000-0002-6760-7830, Martin, T., Webster, R., Cherns, D., Uren, M. and Kuball, M. 2017. Morphological and electrical comparison of Ti and Ta based ohmic contacts for AlGaN/GaN-on-SiC HFETs. Microelectronics Reliability 68 , pp. 2-4. 10.1016/j.microrel.2016.11.002

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Abstract

The morphology and impact on leakage currents of two different ohmic metal stacks for GaN based transistor devices is investigated in this work. The results have implications for the performance and reliability of a GaN transistor device. A low temperature Ta based and a higher temperature anneal Ti based metallization are compared. The low temperature process shows a smoother metal semiconductor interface together with several orders of magnitude lower vertical and lateral leakage compared to the conventional higher temperature process. In addition to the leakage tests, back bias ramping experiments are performed unveiling potential advantages of the conventional approach in mitigating current collapse. However the low leakage will enable higher voltage operation making the low temperature process the preferable choice for high power RF applications, if simultaneously current collapse can be controlled.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Engineering
Subjects:	T Technology > TK Electrical engineering. Electronics Nuclear engineering
Uncontrolled Keywords:	GaN; Transistor; Ohmic contact; Morphology; Leakage current; Current collapse
Publisher:	Elsevier
ISSN:	0026-2714
Related URLs:	Publisher
Date of First Compliant Deposit:	9 January 2017
Date of Acceptance:	3 November 2016
Last Modified:	08 Nov 2023 03:00
URI:	https://orca.cardiff.ac.uk/id/eprint/96726

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