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HL: Fachverband Halbleiterphysik
HL 25: Poster Session: GaN - Optical Properties & Preparation and Characterization & Devices
HL 25.27: Poster
Monday, March 26, 2012, 16:00–19:00, Poster D
Performance Enhancement of InAlN/AlN GaN-HEMTs by using In-Situ SiN Passivation for High Temperature Applications — •Alexander Alexewicz1, Paul Marko1, Mohammed Alomari2, Hannes Behmenburg3, 4, Christoph Giesen3, Michael Heuken3, 4, Dionyz Pogany1, Erhard Kohn2, and Gottfried Strasser1 — 1TU Wien — 2Universität Ulm — 3AIXTRON SE, Herzogenrath — 4RWTH Aachen
We present InAlGaN/AlN GaN high electron mobility transistors (HEMTs) with an optimized MOCVD-grown (metal organic chemical vapor deposition) SiN passivation, compared to the standard PECVD (plasma enhanced CVD)-SiN. Passivating the devices effectively reduces electronically active surface states, which can deteriorate the device performance drastically. In this work, GaN HEMTs are processed on SiC substrate with MOCVD-SiN passivation layers of different thicknesses (5 nm, 30 nm, no passivation). SiN is grown in the same run (in-situ) as the InAlGaN/AlN/GaN heterostructure, before the actual processing of the device, what enhances the interface quality by avoiding surface contamination before deposition of the passivation. The non-passivated devices show a maximum drain current of 0.8 A/mm in DC and 0.5 A/mm in pulsed mode at a gate voltage of 3 V. The 5 nm and 30 nm passivated devices exhibit an improvement of these values by 25 % and 50 % in DC, and 80 % and 140 % in pulsed mode, as well as a strongly reduced electron trapping related current collapse. Due to the better interface quality, this kind of passivation has great potential for high temperature device applications.