Impact of $V_\mathsf {th}$ 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 (
$V_\mathsf {th}$
) instability phenomenon. Both positive and negative
$V_\mathsf {th}$
shifts are reported when device undertakes the voltage bias, but the impact of this
$V_\mathsf {th}$
instability phenomenon on device switching behaviors is less investigated. In this study, the drain-source voltage (
$V_\mathsf {ds}$
) induced bidirectional
$V_\mathsf {th}$
shift in hard-switching condition is characterized and decoupled by an H-bridge based double-pulse test. Subsequently, the influence of
$V_\mathsf {th}$
shift on switching behaviors is theoretically analyzed and demonstrated through SPICE simulation and experiment, showing how a positive shifted
$V_\mathsf {th}$
can reduce the device turn-
on
commutation speed and increase the switching losses, and vice versa. The results suggest that the
$V_\mathsf {th}$
instability phenomenon should be considered in accurate switching modeling.