GaN-channel HEMTs with AlN buffer for high-voltage switching
O. Hilt, F. Brunner, E. Bahat Treidel, M. Wolf and J. Würfl
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79th Device Research Conference (DRC 2021), Santa Barbara, USA, Jun. 20-23, virtual event, ISBN: 978-1-6654-2958-0 (2021).
Abstract:
Lateral GaN-based transistors (HEMTs) for power-electronic switching up to 650 V have not yet approached their theoretical material limit in terms of RONA vs. VBr - unlike Si and SiC based devices. The inherent compromise between breakdown strength and dispersion by the usually required GaN-buffer compensation doping is one reason. Related dispersion effects should be absent when using AlN without any doping as buffer material and the high conduction-band offset at the AlN-buffer / GaN-channel interface (Fig. 1) should effectively confine the GaN transistor channel [1]. This would result into a steeper breakdown voltage scaling with gate-drain distance, than the typically observed 100-120 V/µm in GaN HEMTs with carbon-doped GaN buffer [2].
Ferdinand-Braun-Institut gGmbH, Leibniz Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany
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