Investigation of Saturated RON on GaN Power HEMTs by a Re-Configurable Continuous Switching Platform

In this work, an automatic reconfigurable inductive-load evaluation platform is built to investigate the stress-time-dependent dynamic
${R}_{\text {ON}}$
under various operation modes, i.e., Hard-Switching in Continuous Conduction Mode (HS-CCM), Soft-Switching in Continuous Conduction Mode (SS-CCM), and Soft-Switching in Discontinuous Conduction Mode (SS-DCM). The automatic measurement allows real-time monitoring of dynamic
${R}_{\text {ON}}$
and switching of operation modes rapidly. This study is conducted on commercial Schottky-type PGaN gate device and HD-GIT device. The result shows that the dynamic
${R}_{\text {ON}}$
will gradually saturate under continuous stress without self-heating effect, which is related to the stabilization time of the dynamic trapping/de-trapping process in the gallium nitride (GaN) buffer layer, and the saturated
${R}_{\text {ON}}$
is defined by the stabilized
${R}_{\text {ON}}$
. For Schottky-type p-gate HEMTs, hard-switching (HS) stress exhibits the worst saturated
${R}_{\text {ON}}$
, due to the hot electrons trapped, compared with the case under soft switching (SS) condition. In contrast, for HD-GIT device, HS condition delivers undetectable dynamic
${R}_{\text {ON}}$
, attributed to the hole injection from p-GaN near the drain. These findings provide important new insights on the time-dependent stability of p-GaN gate GaN HEMTs.