Degradation and Mechanism of D-Mode AlGaN/GaN MIS-HEMTs Under the Combination Action of Hydrogen and HTGB Stress

In this article, the effects of hydrogen treatment (HT) and high-temperature gate bias (HTGB) stress on the degradation of AlGaN/GaN metal–insulator–semiconductor (MIS) high electron mobility transistors (HEMTs) were investigated. The dc characteristics show that the device after HT exhibits a negative drift of threshold voltage (
${V}_{\text {th}}$
), an ON-resistance (
${R}_{ \mathrm{ON}}$
) decrease, a subthreshold swing (SS) decrease, and a significant increase of drain–source current (
${I}_{\text {ds}}$
) with respect to the fresh one, while the drain–source resistance and gate leakage current hardly change; the
${C}$
–
${V}$
curve slightly negative drifted and the saturation capacitance significantly reduced. Furthermore, for both the fresh and HT devices, negative shifts of the transfer curves and increases of
${I}_{\text {ds}}$
are observed under a gate bias stress of −10 V, while a gate bias stress of +10 V results in an opposite phenomenon. Similarly, neither drain–source resistance nor gate leakage current exhibits a pronounced change. After HTGB stress, the saturation capacitance of the HT devices increased significantly. The degradation behavior and mechanism of GaN MIS-HEMTs under HT and HTGB stress are analyzed, respectively. The experimental results can provide a useful reference for the design and space application of AlGaN/GaN MIS-HEMTs.