Impact of <inline-formula><tex-math notation="LaTeX">$V_\mathsf {th}$</tex-math></inline-formula> Instability of Schottky-Type p-GaN Gate HEMTs on Switching Behaviors

Schottky-type p-GaN gate gallium nitride high electron mobility transistors suffer from threshold voltage (<inline-formula><tex-math notation="LaTeX">$V_\mathsf {th}$</tex-math></inline-formula>) instability phenomenon. Both positive and negative <inline-formula><tex-math notation="LaTeX">$V_\mathsf {th}$</tex-math></inline-formula> shifts are reported when device undertakes the voltage bias, but the impact of this <inline-formula><tex-math notation="LaTeX">$V_\mathsf {th}$</tex-math></inline-formula> instability phenomenon on device switching behaviors is less investigated. In this study, the drain-source voltage (<inline-formula><tex-math notation="LaTeX">$V_\mathsf {ds}$</tex-math></inline-formula>) induced bidirectional <inline-formula><tex-math notation="LaTeX">$V_\mathsf {th}$</tex-math></inline-formula> shift in hard-switching condition is characterized and decoupled by an H-bridge based double-pulse test. Subsequently, the influence of <inline-formula><tex-math notation="LaTeX">$V_\mathsf {th}$</tex-math></inline-formula> shift on switching behaviors is theoretically analyzed and demonstrated through SPICE simulation and experiment, showing how a positive shifted <inline-formula><tex-math notation="LaTeX">$V_\mathsf {th}$</tex-math></inline-formula> can reduce the device turn-<sc>on</sc> commutation speed and increase the switching losses, and vice versa. The results suggest that the <inline-formula><tex-math notation="LaTeX">$V_\mathsf {th}$</tex-math></inline-formula> instability phenomenon should be considered in accurate switching modeling.