Cryogenic Trapping Effects in GaN-HEMTs: Influences of Fe-Doped Buffer and Field Plates
Journal article, 2025
This article investigates trapping mechanisms in AlGaN/GaN high electron mobility transistors (HEMTs) at cryogenic temperatures (CTs) down to 4.2 K, using pulsed I–V and drain current transient spectroscopy (DCTS) measurements. The results revealed an overall increase of trapping effects at CT. In particular, a substantial increase in current collapse at low temperatures was observed and predominately ascribed to deep acceptor states stemming from the iron (Fe)-doped GaN buffer. In contrast, devices with undoped buffer presented limited signs of trapping, which were only linked to surface and access regions. The aggravation at low temperatures of trapping effects was linked to a slower detrapping dynamic at low temperatures. Furthermore, the incorporation of gate field plates (FPs) led to a substantial attenuation of trapping and reduction of current collapse by a factor of 2.6 at CT in Fe-doped devices. These latter features were ascribed to the ability of the FP to decrease the electrical field along the device, highlighting the increased impact of FP at CTs. The results suggest that an undoped buffer with optimized gate FP could help to improve the reliability of GaN devices at low temperatures.
traps
iron (Fe)
Cryogenic
GaN high electron mobility transistors (HEMTs)
field plates (FPs)
Author
Mohamed Aniss Mebarki
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Ragnar Ferrand-Drake Del Castillo
Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics
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), Electronics Material and Systems
A. Papamichail
Linköping University
Vanya Darakchieva
Lund University
Linköping University
Niklas Rorsman
Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics
François Joint
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Victor Belitsky
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Vincent Desmaris
Chalmers, Space, Earth and Environment, Onsala Space Observatory
IEEE Transactions on Electron Devices
0018-9383 (ISSN) 15579646 (eISSN)
Vol. 72 8 4042-4048Subject Categories (SSIF 2025)
Other Electrical Engineering, Electronic Engineering, Information Engineering
Condensed Matter Physics
DOI
10.1109/TED.2025.3581541