Investigation of Al2O3, Si3N4 and SiO2 Used for Surface Passivation and Gate Dielectric on AlGaN/GaN Metal-Oxide-Semiconductor High Electron Mobility Transistors

Karami, K. , Taking, S., Ofiare, A., Elksne, M. , Dhongde, A., Al-Khalidi, A. and Wasige, E. (2022) Investigation of Al2O3, Si3N4 and SiO2 Used for Surface Passivation and Gate Dielectric on AlGaN/GaN Metal-Oxide-Semiconductor High Electron Mobility Transistors. WOCSDICE EXMATEC 2022, Ponta Delgada (São Miguel island–Azores), 3-6 May 2022.

Abstract

In this work we report on the processing and device characteristics of AlGaN/GaN metal-oxide/insulator-semiconductor high electron mobility transistors (MOS-HEMTs) employing different types of dielectric layers such as SiO2, Si3N4 and Al2O3. A device with a Schottky gate (HEMT structure) was also fabricated for comparison. The AlGaN/GaN MOS-HEMT device employing high-k Al2O3 material for surface passivation and gate dielectric demonstrated the highest maximum drain current density of over 1940 mA/mm and highest maximum peak transconductance of 240 mS/mm. This device also produces the lowest gate leakage current of IGS = 1x10-8 A/mm at VGS = -9 V and the VBR of over 200 V. These results indicate the high quality of Al2O3 material grown using atomic layer deposition (ALD). In contrast, devices employing PECVD (plasma-enhanced chemical vapour deposition) SiO2 and Si3N4 demonstrate poor device performances compared to the Schottky gate structure. These results show the importance of applying a high quality insulator for surface passivation and gate dielectric of the AlGaN/GaN heterostructure.

• Item Type: Conference or Workshop Item
• Additional Information: The authors wish to thank staff at the James Watt Nanofabrication Centre at the University of Glasgow for their support with this work. This work was supported in part by EPSRC grant no. EP/R024413/1.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Wasige, Professor Edward and Dhongde, Aniket and Al-Khalidi, Dr Abdullah and Elksne, Mrs Maira and Karami, Mr Kaivan and Taking, Dr Sanna and Ofiare, Dr Afesomeh
• Authors: Karami, K., Taking, S., Ofiare, A., Elksne, M., Dhongde, A., Al-Khalidi, A., and Wasige, E.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Copyright Holders: Copyright © 2022 The Authors
• Publisher Policy: Reproduced with the permission of the Publisher

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• Organisation

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
301178		Novel GaN Power Devices and Packaging Technologies for 300 degC Ambient Operation	Edward Wasige	Engineering and Physical Sciences Research Council (EPSRC)	EP/R024413/1	ENG - Electronics & Nanoscale Engineering