ORIGINAL RESEARCH article
Front. Mater.
Sec. Semiconducting Materials and Devices
Volume 12 - 2025 | doi: 10.3389/fmats.2025.1666203
Influence of Polarization Engineering in InₓAlᵧGaN₍₁₋ₓ₋ᵧ₎ Back-Barrier on AlGaN Coupled Channel MOS-HEMT with HfO₂ Gate Dielectric for Millimeter-Wave Application
Provisionally accepted
Lakshmi Priya K*
Karthik S- SRM Institute of Science and Technology - Vadapalani Campus Faculty of Engineering and Technology, Chennai, India
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This study investigates a high-performance double-tiered T-gate AlGaN coupled-channel MOS-HEMT that incorporates an InₓAlᵧGaN₍₁₋ₓ₋ᵧ₎ back-barrier and employs HfO₂ as the gate dielectric. The device performance is analyzed using Sentaurus TCAD simulations, which include mobility models, hydrodynamic and thermodynamic effects, piezoelectric polarization, and impact ionization models. The epitaxial structure utilizes an AlGaN coupled-channel to enhance carrier confinement and a lattice-matched InₓAlᵧGaN₍₁₋ₓ₋ᵧ₎ back-barrier to minimize buffer leakage. As a result, the device achieves a drain current of 1.19 A/mm, a peak transconductance of 400 mS/mm, a drain-induced barrier lowering (DIBL) of 72 mV/V, and a threshold voltage (Vth) shift of −2 V. The double-tiered T-gate with field-plate extensions significantly improves breakdown performance, achieving a blocking voltage of 640 V. Furthermore, experimental measurements demonstrate a cut-off frequency (fT) of 206 GHz with a gate length of 60 nm. The device exhibits a substantial improvement in current drive due to the use of a graded AlGaN coupled-channel combined with an InₓAlᵧGaN₍₁₋ₓ₋ᵧ₎ back-barrier, compared to conventional AlGaN composite-channel HEMTs. Additionally, the proposed design demonstrates enhanced frequency performance, making it a promising solution for high-efficiency power switching and millimeter-wave applications.
Keywords: AlGaN/GaN, MOSHEMT, InAlGaN Back Barrier, Coupled channel, HfO2 dielectric
Received: 15 Jul 2025; Accepted: 12 Sep 2025.
Copyright: © 2025 K and S. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Lakshmi Priya K, SRM Institute of Science and Technology - Vadapalani Campus Faculty of Engineering and Technology, Chennai, India
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