Optimization of the Design of Terahertz Detectors Based on Si CMOS and AlGaN/GaN Field-Effect Transistors

M. Bauer1, S. Boppel1,2, J. Zhang1, A. Rämer2, S. Chevtchenko2, A. Lisauskas1,3, W. Heinrich2, V. Krozer1,2, H.G. Roskos1

Published in:

Int. J. Hi. Spe. Ele. Syst., vol. 25, no. 03/04, pp. 1640013 (2016).

Copyright © 2016 World Scientific Publishing Co Pte Ltd. 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 World Scientific Publishing Co Pte Ltd.

Abstract:

TeraFETs are THz power detectors based on field-effect transistors (FETs) integrated with antennas. The first part of this paper discusses the design of Si CMOS TeraFETs leading to an optimized noise-equivalent power close to the room-temperature limit. The impact of the choice of the gate width and gate length, the role of the parasitic effects associated with the technology node, and the conjugate matching of antenna and FET impedance – which is possible over narrow THz frequency bands because of the frequency dependence of the channel impedance resulting from plasmonic effects – are highlighted. Taking these aspects into account, we implement narrow-band detectors of two different designs. Using a 90-nm and a 65-nm CMOS technology, we reach a room-temperature cross-sectional NEP of 10 pW/vHz at 0.63 THz. We then explore the optimization of AlGaN/GaN TeraFETs equipped with broadband antennae. A room-temperature optical NEP of 26 pW/vHz is achieved around 0.5 THz despite the fact that the existence of pronounced ungated regions leads to a significant hot-electron thermoelectric DC voltage reducing the rectified signal. AlGaN/GaN TeraFETs become competitive and they have the added advantage that they are extraordinarily robust against electrostatic shock even without inclusion of protection diodes into the design.

1 Physikalisches Institut, Goethe-Universität, Max-von-Laue-Str. 1, 60438 Frankfurt am Main, Germany
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
3 Department of Radiophysics, Faculty of Physics, Sauletekio al. 9, bldg. III, Vilnius University, LT-10222 Vilnius, Lithuania

Keywords:

Terahertz; field-effect transistors; distributed resistive and plasmonic mixing; noise equivalent power; hot-electron thermoelectric effect.