Optimization of ohmic contact for AlGaN/GaN HEMT on low-resistivity silicon

Benakaprasad, B., Eblabla, A. M., Li, X. , Crawford, K. G. and Elgaid, K. (2020) Optimization of ohmic contact for AlGaN/GaN HEMT on low-resistivity silicon. IEEE Transactions on Electron Devices, 67(3), pp. 863-868. (doi: 10.1109/TED.2020.2968186)

Abstract

In this article, we report the optimization of ohmic contact formation on AlGaN/GaN on low-resistivity silicon. For achieving this, a strategy of uneven AlGaN/GaN was introduced through patterned etching of the substrate under the contact. Various pattern designs (holes, horizontal lines, vertical lines, grid) and varied etch depth (above and below the 2-D electron gas) were investigated. Furthermore, a study of planar and nonplanar ohmic metallization was investigated. Compared to a traditional fabrication strategy, we observed a reduced contact resistance from 0.35 to 0.27 Ω · mm by employing a grid etching approach with a “below channel” etch depth and nonplanar ohmic metallization. In general, measurements of “below channel” test structures exhibited improved contact resistance compared to “above channel” in both planar and nonplanar ohmic metallization.

• Item Type: Articles
• Additional Information: This work was supported by the Engineering and Physical Sciences Research Council under Grant EP/N014820/2 and Grant EP/P006973/1.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Elgaid, Dr Khaled and Li, Dr Xu and Benakaprasad, Miss Bhavana and Eblabla, Mr Abdalla and Crawford, Mr Kevin
• Authors: Benakaprasad, B., Eblabla, A. M., Li, X., Crawford, K. G., and Elgaid, K.
• College/School: College of Science and Engineering > School of Engineering; College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: IEEE Transactions on Electron Devices
• Publisher: IEEE
• ISSN: 0018-9383
• ISSN (Online): 1557-9646
• Published Online: 11 February 2020
• Copyright Holders: Copyright © 2020 IEEE
• First Published: First published in IEEE Transactions on Electron Devices 67(3): 863-868
• Publisher Policy: Reproduced in accordance with the publisher copyright policy