On the Abnormal Reduction and Recovery of Dynamic RON Under UIS Stress in Schottky p-GaN Gate HEMTs

In this letter, the abnormal reduction and recovery of dynamic
R
_ON
are observed under unclamped-inductive-switching (UIS) stress in Schottky p-GaN gate HEMTs. The reduction of
R
_{ON_dyn}
exhibits a positive dependence on UIS stress (
V
_PEAK
, peak voltage). With the help of
Sentaurus
simulation, the underlying physical mechanism is revealed. During UIS stress, the
e-h
pairs generated by impact ionization can be trapped, and the detrapping of electrons is faster than holes because of the lower time constant, which results in the reduction of
R
_{ON_dyn}
. Furthermore, a mathematic model of
R
_{ON_dyn}
after UIS stress is developed and verified by measurement. This work could provide practical guidance for the UIS operation setup to reduce the
R
_ON
and conduction loss of GaN HEMTs.