A High-Sensitivity AlGaN/GaN HEMT Terahertz Detector With Integrated Broadband Bow-Tie Antenna

M. Bauer1,2, A. Rämer3, S.A. Chevtchenko3, K.Y. Osipov3, D. Cibiraite1, S. Pralgauskaite4, K. Ikamas4,5, A. Lisauskas1,4,6, W. Heinrich3, V. Krozer1,3, and H.G. Roskos1

Published in:

IEEE Trans. Terahertz Sci. Technol., vol. 9, no. 4, pp. 430-444 (2019).

Copyright © 2019 IEEE - All rights reserved. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.


Many emerging applications in the terahertz (THz)frequency range demand highly sensitive, broadband detectors for room-temperature operation. Field-effect transistors with integrated antennas for THz detection (TeraFETs) have proven to meet these requirements, at the same time offering great potential for scalability, high-speed operation, and functional integrability. In this contribution, we report on an optimized field-effect transistor with integrated broadband bow-tie antenna for THz detection (bow-tie TeraFET) and compare the detector’s performance to other state-of-the-art broadband THz detector technologies. Implemented in a recently developed AlGaN/GaN MMIC process, the presented TeraFET shows a more than twice performance improvement compared to previously fabricated AlGaN/GaN-HEMT-based TeraFETs. The detector design is the result of detailed modeling of the plasma-wave-based detection principle embedded in a full-device detector model to account for power coupling of the THz radiation to the intrinsic gated FET channel. The model considers parasitic circuit elements as well as the high-frequency impedance of the integrated broadband antenna, and also includes optical losses from a silicon substrate lens. Calibrated characterization measurements have been performed at room temperature between 490 and 645 GHz, where we find values of the optical (total beam power referenced) noise-equivalent power of 25 and 31 pW/√Hz at 504 and 600 GHz, respectively, in good agreement with simulation results. We then show the broadband detection capability of our AlGaN/GaN detectors in the range from 0.2 to 1.2 THz and compare the TeraFETs’ signal-to-noise ratio to that of a Golay cell and a photomixer. Finally, we demonstrate animaging application in reflection geometry at 504 GHz and determine a dynamic range of >40 dB.

1 was with Physikalisches Institut, Johann Wolfgang Goethe-Universität, D-60438 Frankfurt am Main, Germany
2 now with the Center for Materials Characterization and Testing, Fraunhofer ITWM, D-67663 Kaiserslautern, Germany
3 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, 12489 Berlin, Germany
4 Institute of Applied Electrodynamics and Telecommunications, Vilnius University, LT-10257 Vilnius, Lithuania
5 General Jonas Zemaitis Military Academy of Lithuania, LT-10322 Vilnius, Lithuania
6 Center for Terahertz Researchand Applications, Institute of High Pressure Physics PAS, PL-01-142 Warsaw, Poland

Index Terms:

Broadband antenna, field-effect transistors, GaNHEMT, plasmonic mixing, terahertz (THz) detectors.