【Device Papers】Performance of κ-Ga₂O₃/GaN HEMTs and Normally off Operation by p-GaN Gate

      Researchers from Wuxi University of Technology have published a dissertation titled " Performance of κ-Ga₂O₃/GaN HEMTs and Normally off Operation by p-GaN Gate " in Micro.

Abstract

      The κ-phase gallium oxide (κ-Ga₂O₃) has emerged as a promising material for next-generation electronic devices owing to its ultra-wide band gap, remarkable spontaneous polarization and unique ferroelectricity. We have investigated the two-dimensional electron gas (2DEG) characteristics and device performance of κ-Ga₂O₃/GaN HEMTs via numerical simulations. The κ-Ga₂O₃/GaN heterostructure exhibits a significantly enhanced 2DEG density (~1.05 × 10¹⁴ cm⁻²), which is nearly an order of magnitude higher than that of conventional AlGaN/GaN HEMTs, due to the strong polarization effect. For a barrier thickness of 25 nm, the κ-Ga₂O₃/GaN HEMT exhibits a maximum drain current density (I_D,max) of 4.40 A/mm at V_GS = 2 V and a peak transconductance (g_m,max) of 0.45 S/mm, accompanied by a steep subthreshold swing (SS) of 63.2 mV/decade. Furthermore, we find that the absolute value of threshold voltage increases with the barrier thickness and the peak transconductance decreases with the increase in barrier thickness. When the thickness reaches 40 nm, the 2DEG density becomes saturated with a value of 1.12 × 10¹⁴ cm⁻². Moreover, by incorporating a p-type GaN cap layer into the κ-Ga₂O₃/GaN heterostructure, a normally off operation is achieved, with a positive threshold voltage as the acceptor concentration exceeds 8.0 × 10¹⁷ cm⁻³. These results highlight the potential of κ-Ga₂O₃/GaN heterostructures for high-performance power electronic applications.

DOI：

https://doi.org/10.3390/micro6030048