Influence of assorted back barriers on AlGaN/GaN HEMT for 5G K-band applications

In this letter, the RF and DC performance of Al0.25Ga0.75N/GaN HEMT is examined using different back barrier layers. Significantly, it has improved the electron confinement towards the GaN channel. it exhibits the maximum drain current density (Id) of 859 mA/mm for AlGaN back barrier HEMT, 847 mA/mm for InGaN back barrier HEMT, and 829 mA/mm for AlN back barrier HEMT at VDs=5 V and VGS=0 V. In addition, it achieves the peak transconductance (gm) of 291 mS/mm for AlGaN back barrier HEMT, 286 mS/mm for InGaN back barrier HEMT and 281 mS/mm for AlN back barrier HEMT. Furthermore, the HEMT with AlGaN as back barrier enhanced the (fT) current-gain cutoff frequency from 17.42 GHz to 26.07 GHz. Besides, the drain leakage current into buffer layer is effectively controlled by a strong AlGaN back barrier, confirming better electron confinement towards the GaN channel to boost the RF performance of Al0.25Ga0.75N/GaN HEMT. Hence, the HEMT with AlGaN back barrier stands superior in DC and RF performance than the HEMT with InGaN and AlN back barriers.