GaN High-Electron-Mobility Transistors with Superconducting Nb Gates for Low-Noise Cryogenic Applications
Journal article, 2023

The successful integration of superconducting niobium (Nb) gate electrodes into cryogenic gallium nitride (GaN)-based high-electron-mobility transistors (HEMTs) is reported. This is achieved through a specifically developed microfabrication process. The device's DC, microwave, and noise performances at cryogenic temperatures, down to 4 K, are studied and presented. The superconductivity of the gate is tested using DC end-to-end measurements. A clear superconducting state transition at a critical temperature, Tc, of ≈9.2 K is shown. This is further verified with GaN HEMTs with two gate fingers and a gate length of 0.2 μm, through the extraction and validation of a small-signal model at T < Tc. Additionally, the superconductivity of the gate is verified for several gate widths and lengths, showing a significant reduction of the gate resistance independently of its dimensions. Finally, a comparative study of the cryogenic microwave noise performances of the GaN HEMTs with gold (Au) and Nb gates is presented. The Au-gated device presents a competitive optimum noise temperature, Tmin-opt, of ≈8 K at 5 GHz, demonstrating the potential of this technology for cryogenic low-noise applications. The Nb-gated device presents a 5 K higher Tmin-opt, which is found to be related to the suppression of the superconductivity of the Nb gate at the optimum-noise bias.

Cryogenic

High electron mobility transistor (HEMT)

Superconductivity

Gallium Nitride (GaN)

Niobium (Nb)

Author

Mohamed Aniss Mebarki

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Ragnar Ferrand-Drake Del Castillo

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Alexey Pavolotskiy

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Denis Meledin

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Erik Sundin

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Mattias Thorsell

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Niklas Rorsman

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Victor Belitsky

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Vincent Desmaris

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Physica Status Solidi (A) Applications and Materials Science

1862-6300 (ISSN) 1862-6319 (eISSN)

Vol. 220 8 2200468

Subject Categories

Materials Engineering

Other Physics Topics

Electrical Engineering, Electronic Engineering, Information Engineering

Nano Technology

Condensed Matter Physics

DOI

10.1002/pssa.202200468

More information

Latest update

7/5/2023 1