Comprehensive Study of Human-Body-Model Electrostatic Discharge on p-GaN Gate Power HEMT with AlGaN Barrier Spacers

This paper presents an investigation into the improvement of gate ESD robustness in Schottky gate p-GaN high electron mobility transistors (HEMTs) through the utilization of gate epitaxial engineering. The proposed device with optimized AlGaN spacers features comparable DC on-state and off-state performances, while the forward gate-to-source (G-S) and gate-to-source (G-D) of the Human-Body-Model (HBM) Electrostatic Discharge (ESD) capability is significantly boosted from 300 V to 3.5 kV, meeting the JEDEC JS-001-2023 Class 2 standard compared to that without an AlGaN spacer structure. In addition, the influences of HBM stress on the device stability and reliability has been evaluated. The proposed device shows negligible shifts in time-dependent gate breakdown (TDGB) and dynamic performance after being subjected to G-S HBM ESD testing under the Class 2 standard. At a high HBM voltage of 3.5 kV, the proposed mechanism explains the accumulation of holes at the p-GaN/AlGaN and AlGaN/GaN interfaces, which lowers barriers and improves electron conduction capabilities and uniformity under the gate, thereby alleviating current crowding. The reverse G-S HBM ESD capability strongly depends on the reverse blocking voltage of the gate-to-source terminal. As a result, this study has proposed a potential solution without gate ESD protection circuits, enabling the achievement of HBM ESD capability within specification.