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Cryogenic Trapping Effects in GaN-HEMTs : Influences of Fe-Doped Buffer and Field Plates

Mebarki, Mohamed Aniss LU ; Castillo, Ragnar Ferrand-Drake Del ; Meledin, Denis ; Sundin, Erik ; Thorsell, Mattias ; Papamichail, Alexis ; Darakchieva, Vanya LU ; Rorsman, Niklas ; Joint, Francois and Belitsky, Victor , et al. (2025) In IEEE Transactions on Electron Devices 72(8). p.4042-4048
Abstract
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,... (More)
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. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
IEEE Transactions on Electron Devices
volume
72
issue
8
pages
7 pages
publisher
IEEE - Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • scopus:105009057417
ISSN
0018-9383
DOI
10.1109/TED.2025.3581541
language
English
LU publication?
yes
id
50b0c12b-f50d-4e12-ba53-e3c99b1b1d8c
date added to LUP
2025-11-06 10:44:16
date last changed
2025-11-10 14:25:07
@article{50b0c12b-f50d-4e12-ba53-e3c99b1b1d8c,
  abstract     = {{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.}},
  author       = {{Mebarki, Mohamed Aniss and Castillo, Ragnar Ferrand-Drake Del and Meledin, Denis and Sundin, Erik and Thorsell, Mattias and Papamichail, Alexis and Darakchieva, Vanya and Rorsman, Niklas and Joint, Francois and Belitsky, Victor and Desmaris, Vincent}},
  issn         = {{0018-9383}},
  language     = {{eng}},
  month        = {{08}},
  number       = {{8}},
  pages        = {{4042--4048}},
  publisher    = {{IEEE - Institute of Electrical and Electronics Engineers Inc.}},
  series       = {{IEEE Transactions on Electron Devices}},
  title        = {{Cryogenic Trapping Effects in GaN-HEMTs : Influences of Fe-Doped Buffer and Field Plates}},
  url          = {{http://dx.doi.org/10.1109/TED.2025.3581541}},
  doi          = {{10.1109/TED.2025.3581541}},
  volume       = {{72}},
  year         = {{2025}},
}