| Title |
Dynamic Ron Characteristics on AlGaN/GaN-on-Si HFETs with Different Carbon-Doped GaN Layer Thickness |
| DOI |
https://doi.org/10.5370/KIEE.2026.75.6.1297 |
| Keywords |
AlGaN/GaN; GaN-on-Si; Carbon-doped GaN; Dynamic Ron; Current collapse |
| Abstract |
This paper investigates the effect of carbon-doped GaN (C-GaN) layer thickness on the dynamic on-resistance (dynamic Ron) of AlGaN/GaN-on-Si heterojunction field-effect transistors (HFETs) using TCAD simulation. Three structures with different C-GaN thicknesses of 0.6, 0.9, and 1.2 μm were compared while keeping the unintentionally doped GaN (U-GaN) channel and AlGaN barrier identical. Off-state stress was applied at VGS=-10 V and VDS=25~300 V for 1000 s, followed by on-state recovery at VGS=0 V and VDS=1 V. Dynamic Ron was extracted from the drain current at 1 ms after turn-on. The results show that dynamic Ron increases as the C-GaN thickness increases under both transport conditions considered in this study. Electric field analysis reveals that thicker C-GaN causes stronger electric field concentration in the channel and buffer regions after off-state stress, resulting in slower 2DEG recovery. In addition, the case with relatively larger vertical leakage shows reduced channel electric field and smaller dynamic Ron, indicating that partial charge neutralization can mitigate buffer-induced current collapse. These results suggest that the thickness of the C-GaN layer is an important design parameter for improving dynamic switching performance in GaN-on-Si HFETs. |