【Device Papers】Performance enhancement of asymmetric gate graded-AlGaN/GaN HEMT on β-Ga₂O₃ substrate for RF applications

      Researchers from the University of Delhi have published a dissertation titled "Performance enhancement of asymmetric gate graded-AlGaN/GaN HEMT on β-Ga₂O₃ substrate for RF applications" in Materials Science and Engineering: B.

Abstract

      This study examines asymmetric gate AlGaN/GaN HEMTs on β-Ga₂O₃ substrate with different gate positioning and graded Al composition (0%–30%) in AlGaN barrier. The graded design improves electron mobility by reducing Al concentration, minimizing scattering, and enabling E-mode operation. It also flattens transconductance peaks and mitigates short-channel effects. Although 2DEG density decreases slightly, it is restored by n⁺ GaN-doped contacts. The β-Ga₂O₃ substrate reduces lattice mismatch with GaN thereby boosting drain current and cut-off frequency. A peak transconductance of 640 mS/mm, cutoff frequency of 55 GHz, and maximum frequency of oscillation of 125 GHz have been obtained. It has been found that optimized gate placement (0.25 μm from source) yields a gain-frequency product of 2352.24 GHz and gain-bandwidth product of 386.82 GHz for 5 μm channel and 0.2 μm gate length. These results highlight superior DC and RF performance of the proposed device making it a promising candidate for high-frequency applications.

DOI：

https://doi.org/10.1016/j.mseb.2025.118514