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Low Source/Drain Contact Resistance for AlGaN/GaN HEMTs with High Al Concentration and Si-HP [111] Substrate / S. J. Duffy; B. Benbakhti; M. Mattalah; W. Zhang; M. Bouchilaoun; M. Boucherta; K. Kalna; N. Bourzgui; H. Maher; A. Soltani

ECS Journal of Solid State Science and Technology, Volume: 6, Issue: 11, Pages: S3040 - S3043

Swansea University Author: Kalna, Karol

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DOI (Published version): 10.1149/2.0111711jss

Abstract

An optimized fabrication process of ohmic contacts is proposed to reduce the source/drain access resistance (RC) and enhance DC/RF performance of AlGaN/GaN HEMTs with a high Al concentration. We show that source/drain RC can be considerably lowered by (i) optimally etching into the barrier layer usi...

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Published in: ECS Journal of Solid State Science and Technology
ISSN: 2162-8769 2162-8777
Published: 2017
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URI: https://cronfa.swan.ac.uk/Record/cronfa35704
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Abstract: An optimized fabrication process of ohmic contacts is proposed to reduce the source/drain access resistance (RC) and enhance DC/RF performance of AlGaN/GaN HEMTs with a high Al concentration. We show that source/drain RC can be considerably lowered by (i) optimally etching into the barrier layer using Ar+ ion beam, and by (ii) forming recessed contact metallization using an optimized Ti/Al/Ni/Au (12 nm/200 nm/40 nm/100 nm) multilayers. We found that a low RC of ∼0.3 Ω.mm can be achieved by etching closer to the 2-Dimensional Electron Gas (2DEG) at an optimum etching depth, 75% of the barrier thickness, followed by a rapid thermal annealing at 850°C. This is due to the very small distance between the alloy and the 2DEG (higher electric field) as shown by 2D drift-diffusion simulations combined with Transmission Line Model (TLM) extractions.
Keywords: AlGaN/GaN HEMTs, Ohmic Contact, TLM Model
College: College of Engineering
Issue: 11
Start Page: S3040
End Page: S3043