Enhanced Single-Event Hardness in GaN-on-Si HEMT With Gate-Junction Termination Extension

In this work, we demonstrate a radiationhardened p-GaN HEMT featuring gate-junction termination extension (G-JTE) on an industry-standard GaN-on-Si platform. By virtue of the G-JTE structure to modulate the electric field in the irradiation-sensitive area (i.e., the gate edge), the G-JTE HEMT can deliver single-event burnout (SEB) voltage of 375 V and 475 V under linear energy transfer (LET) of $86 \text{MeV} \cdot \text{cm}^{2} / \text{mg}$ and $38 \text{MeV} \cdot \text{cm}^{2} / \text{mg}$, whereas a low on-resistance ($\boldsymbol{R}_{\text{ON}}$) of $7.0 \Omega \cdot \text{mm}$ (or $0.95 \mathrm{m} \Omega \cdot \text{cm}^{2}$) is simultaneously maintained with gate-to-drain spacing ($L_{\text {GD }}$) of $6 \mu \mathrm{m}$. The mechanisms of the radiation hardening have been investigated by emission microscopy (EMMI) and channelpotential monitoring characterizations, whereby the electric field suppression and depletion region extension by the G-JTE are experimentally verified. Furthermore, the G-JTE HEMT can also exhibit suppressed dynamic $\boldsymbol{R}_{\text {ON }}$ degradation ($\sim 13 \%$) after switching from high OFF-state bias stress of 600 V. The radiation-hardening technique as well as the characterizations for mechanism investigation in this work are valuable towards single-event hardness of GaN devices for high-efficiency applications in harsh radiation environments.