Demonstration of high Johnson’s figure of merit (<i>f</i> <sub>t</sub> × V<sub>BR</sub> >20 THz·V) and <i>f</i> <sub>max</sub> × V<sub>BR</sub> (>42 THz·V) for Al<sub>0.66</sub>Ga<sub>0.34</sub>N channel MISHEMT on bulk AlN substrates
Ruixin Bai, Swarnav Mukhopadhyay, Khush Gohel, Surjava Sanyal, Jiahao Chen, Md Tahmidul Alam, Shuwen Xie, Shubhra S. Pasayat, Chirag Gupta
Abstract
Abstract In this paper, a metal-organic chemical vapor deposition (MOCVD) grown Al 0.66 Ga 0.34 N channel metal-insulator-semiconductor-high-electron-mobility-transistor (MISHEMT) with a scaled T-gate structure was fabricated on a single-crystal bulk AlN substrate. A device with 4 μm source-to-drain spacing achieved a record-high Johnson’s figure of merit (JFOM) of 20.92 THz·V, enabled by the high-Al channel, high-quality substrate, and gate field-plate. The corresponding cutoff and maximum oscillation frequencies are 22.5 GHz and 46 GHz, respectively, with a breakdown voltage of 930 V. A current collapse of 15% was observed under 30 V drain bias, indicating excellent radio-frequency (RF) performance and the potential of bulk-AlN-based AlGaN channel high-electron-mobility-transistors (HEMTs) for advanced RF applications.