Low-Side GaN Power Device Dynamic Ron Characteristics Under Different Substrate Biases

Dynamic on-resistance $(\pmb{R}_{on})$ characteristics of low-side GaN-on-Si power devices under different substrate biases are investigated. Multiple-pulse techniques have been applied to mimic the monolithically integrated half-bridge GaN power switching conditions. Compared with the grounded substrate, a negative substrate bias not only yields asymmetric vertical leakage, but also induces distinct injected electrons to interact with the buffer traps. Pulse-mode substrate bias is also studied to suppress dynamic $\pmb{R}_{on}$ degradation due to elimination of back-gating effect. A novel mitigation technique is proposed and verified by experiments.