Characterization of GaN HEMTs' Aging Precursors and Activation Energy Under a Wide Range of Thermal Cycling Tests

In this article, 650-V/7.5-A-rated enhancement-mode gallium nitride (GaN) high-electron-mobility transistors (HEMTs) with integrated gate drivers are characterized under thousands of accelerated thermal cycling (ATC) at different junction temperature stresses. This research helps in developing fundamental insights into GaN HEMTs' aging characteristics through the degradation of 10 devices under ATC tests. For over 20 000 thermal cycles, the forward and reverse conduction losses,
I
_GSS
,
C
_oss
, and the RDS
_on
are experimentally measured to identify the parameter shifts and the corresponding precursors. Results indicate that both
I
_GSS
and
C
_oss
do not deviate much, but the values of RDS
_on
, the forward and reverse conduction losses vary considerably with device aging. This article also presents an empirical method to estimate the correlation between the acceleration factors of the GaN FETs' degradation process and the thermal cycling conditions. The value of the activation energy of the tested GaN HEMT devices is also derived using the empirical equations to be about 1.13 eV under the applied stress factors. This study finds that the degradation process of GaN HEMTs with age facilitates a reasonable correlation with different failure mechanisms, which further helps in reliability improvement.