Suppressed Hole-Induced Degradation in E-mode GaN MIS-FETs with Crystalline $\text{GaO}_{\mathrm{x}}\mathrm{N}_{1-\mathrm{x}}$ Channel

Under reverse-bias stress with a high drain voltage, hole-induced gate dielectric degradation in the E-mode GaN MIS-FETs could lead to non-recoverable $V_{\text{TH}}$ shifts and devastating time-dependent breakdown. Such a degradation can be effectively suppressed by converting the GaN channel into a crystalline $\text{GaO}_{\mathrm{x}}\mathrm{N}_{1-\mathrm{x}}$ channel in the gated region. The valence band offset between $\text{GaO}_{\mathrm{x}}\mathrm{N}_{1-\mathrm{x}}$ and the surrounding GaN creates a hole-blocking ring around the gate dielectric, preventing holes from flowing to the gate dielectric and therefore mitigating the hole-induced degradation.