This study investigates the DC and RF performance of two device structures, AlGaN/GaN/AlGaN and AlGaN/GaN/β-Ga2O3, and analyzes the impact of ultra-wide bandgap back barrier(BB) engineering using beta-Gallium Oxide (β-Ga2O3) with an energy bandgap of 4.9 eV on the RF characteristics of high-electron-mobility transistors (HEMTs) on Silicon Carbide (SiC) substrate. Compared to AlGaN/GaN/AlGaN, the AlGaN/GaN/β-Ga2O3 structure offers improved electron confinement and reduced buffer leakage, resulting in enhanced output current and higher cutoff frequency for RF applications.The AlGaN/GaN/AlGaN device delivers a drain current of 4.4506 A/mm, a transconductance of 1.09 S/mm, a cut-off frequency of 198 GHz, and a breakdown voltage of 45 V. In comparison, the AlGaN/GaN/β-Ga2O3 device achieves a higher drain current of 5.39072 A/mm, an improved transconductance of 1.22 S/mm, an increased cut-off frequency of 228 GHz, and a significantly enhanced breakdown voltage of 84 V. The β-Ga2O3-based HEMT delivers a significant performance improvement of over 20% compared to the AlGaN-based HEMT. These results highlight the superior electrical performance of the AlGaN/GaN/β-Ga2O3 structure over the conventional AlGaN/GaN/AlGaN design. The enhanced performance originates from the deeper quantum well and higher conduction band offset provided by the β-Ga2O3 back barrier, which significantly improves electron confinement and reduces buffer-related scattering.
Nelson et al. (Thu,) studied this question.