Enhancing DC and RF Performance of AlGaN/GaN HEMTs Using Delta-Doped Double Barriers and 4H-SiC Substrates

Abstract

This study aims to enhance the direct current (DC) and radio-frequency (RF) performance of an AlGaN/GaN high electron mobility transistor (HEMT) employing a T-shaped gate structure. We propose a novel device architecture featuring a delta-doped double AlGaN barrier layer combined with a 4H-SiC substrate, leveraging its superior thermal conductivity and electrical properties. Device performance was evaluated using Silvaco TCAD simulation tools. The optimized design, incorporating a 4 nm thick delta-doped double AlGaN barrier, significantly improves electron mobility and device performance. Simulation results reveal a maximum drain current of 0.987 A and a peak transconductance of 698 mS/mm at a drain-source voltage of 3 V. Furthermore, the device demonstrates exceptional high-frequency performance, achieving a cut-off frequency (fT) of 748 GHz and a maximum oscillation frequency (fmax) of 1068.8 GHz. These results underscore the efficacy of the proposed delta-doped double barrier design and 4H-SiC substrate in enabling high-performance HEMTs for high-power and high-frequency applications.