Low Trapping Effects and High Electron Confinement in Short AlN/GaN-On-SiC HEMTs by Means of a Thin AlGaN Back Barrier

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 non-intentionally 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 V-DS = 20 V. These results demonstrate the interest of this approach for future millimeter-wave applications.

Automated summary

This paper presents an enhancement of mm-wave power performances using a vertically scaled AlN/GaN heterostructure. The introduction of an AlGaN back barrier underneath a non-intentionally doped GaN channel layer prevents punch-through effects and drain leakage current, while maintaining a moderate carbon concentration in the buffer layer. By carefully tuning the Al concentration in the back barrier layer, the optimized heterostructure provides electron confinement and low trapping effects up to high drain bias for a gate length as short as 100 nm. Load-Pull measurements at 40 GHz showed outstanding performances with a record power-added efficiency of 70% (66%) under high output power density at V-DS = 20 V. These results demonstrate the potential of this approach for future millimeter-wave applications.