High-performance GaN-based HEMTs with β-Ga2O3 buffer layer engineering for millimeter-wave applications

This article presents a comprehensive theoretical analysis of device characteristics achievable through innovative channel engineering and buffer layer optimization using validated TCAD simulation models. The AlGaN/InGaN/GaN HEMT (L_G = 55 nm) demonstrates impressive performance metrics, including a sheet carrier density of 2.6 × 10¹³ cm⁻², on-resistance of 0.31 Ω.mm, and maximum drain current density of 3.14 A/mm. The device achieves a peak transconductance of 0.71 S/mm and exhibits robust breakdown characteristics with a three-terminal off-state breakdown voltage of 96.8 V. In addition, it maintains an excellent I_ON/I_OFF ratio of 10¹³ and demonstrates outstanding frequency performance with f_T/f_max values of 285/310 GHz. The InAlN/InGaN/GaN architecture shows enhanced performance parameters, featuring a higher sheet carrier density of 3.9 × 10¹³ cm⁻², reduced on-resistance of 0.25 Ω.mm, and increased drain current density of 5.22 A/mm. This configuration achieves a peak transconductance of 0.74 S/mm, while maintaining a breakdown voltage of 57.1 V and an I_ON/I_OFF ratio of 10¹³. Notably, it demonstrates superior frequency characteristics with f_T/f_max values reaching 311/364 GHz. These results highlight the potential of β-Ga₂O₃ buffer engineering in advancing GaN HEMT technology for next-generation millimeter-wave applications.