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Low Trapping Effects and High Electron Confinement in Short AlN/GaN-on-SiC HEMTs by Means of a Thin AlGaN Back Barrier
Archive ouverte : Article de revue
International audience. In this paper, we report on an enhancement of mm-wave power performances with a vertically scaled AlN/GaN heterostructure. An AlGaN back barrier is introduced underneath a nonintentionally doped GaN channel layer, enabling the prevention of punch-through effects and related drain leakage current under a high electric field while using a moderate carbon concentration into the buffer. By carefully tuning the Al concentration into the back barrier layer, the optimized heterostructure offers a unique combination of electron confinement and low trapping effects up to high drain bias for a gate length as short as 100 nm. Consequently, pulsed (CW) Load-Pull measurements at 40 GHz revealed outstanding performances with a record power-added efficiency of 70% (66%) under high output power density at VDS = 20 V. These results demonstrate the interest of this approach for future millimeter-wave applications.