Operational Characteristics of Various AlGaN/GaN High Electron Mobility Transistor Structures Concerning Self-Heating Effect

This study investigated DC characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) considering self-heating effect (SHE) with basic T-gate (BT), drain-side extended T-gate (DSET), and source-bridge FP (SBFP) structures. We analyzed threshold voltage, transconductance, drain saturation current, and breakdown voltage of each structure for device optimization. Experimental data were initially matched with simulated data for the BT structure, then DC characteristics were compared with the drift-diffusion, coupled drift-diffusion and self-heating models for basic T-gate HEMT devices. Breakdown voltages were measured to identify the optimum DSET structure length, while increasing drain-side gate head to 3 µm. An SBFP was also employed where the DSET device showed highest breakdown voltage. Therefore, DC characteristics were compared for three structures and contrasted to reduce SHE. Hot spot and overall temperature were also analyzed for each structure.