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

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Title: Cryogenic Trapping Effects in GaN-HEMTs: Influences of Fe-Doped Buffer and Field Plates
Authors: Mebarki, Mohamed Aniss, Castillo, Ragnar Ferrand-Drake Del, Meledin, Denis, Sundin, Erik, Thorsell, Mattias, Papamichail, Alexis, Darakchieva, Vanya, Rorsman, Niklas, Joint, Francois, Belitsky, Victor, Desmaris, Vincent
Contributors: Lund University, Faculty of Engineering, LTH, Competence centers, LTH, C3NiT: Centre for III nitride technology, Lunds universitet, Lunds Tekniska Högskola, Kompetenscentrum, LTH, C3NiT: Centrum för III-nitridteknologi, Originator, Lund University, Faculty of Engineering, LTH, LTH Profile areas, LTH Profile Area: The Energy Transition, Lunds universitet, Lunds Tekniska Högskola, LTH profilområden, LTH profilområde: Energiomställningen, Originator, Lund University, Profile areas and other strong research environments, Lund University Profile areas, LU Profile Area: Light and Materials, Lunds universitet, Profilområden och andra starka forskningsmiljöer, Lunds universitets profilområden, LU profilområde: Ljus och material, Originator, Lund University, Faculty of Engineering, LTH, LTH Profile areas, LTH Profile Area: Nanoscience and Semiconductor Technology, Lunds universitet, Lunds Tekniska Högskola, LTH profilområden, LTH profilområde: Nanovetenskap och halvledarteknologi, Originator, Lund University, Profile areas and other strong research environments, Strategic research areas (SRA), NanoLund: Centre for Nanoscience, Lunds universitet, Profilområden och andra starka forskningsmiljöer, Strategiska forskningsområden (SFO), NanoLund: Centre for Nanoscience, Originator, Lund University, Faculty of Science, Department of Physics, Solid State Physics, Lunds universitet, Naturvetenskapliga fakulteten, Fysiska institutionen, Fasta tillståndets fysik, Originator
Source: IEEE Transactions on Electron Devices. 72(8):4042-4048
Subject Terms: Natural Sciences, Physical Sciences, Condensed Matter Physics (including Material Physics, Nano Physics), Naturvetenskap, Fysik, Den kondenserade materiens fysik (Här ingår: Materialfysik, nanofysik)
Description: 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.
Access URL: https://doi.org/10.1109/TED.2025.3581541
Database: SwePub
Description
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.
ISSN:00189383
15579646
DOI:10.1109/TED.2025.3581541