Investigation of trapping effects on AlGaN/GaN HEMT under DC accelerated life testing

Abstract

GaN-based high electron mobility transistors (HEMTs) were subjected to DC-based accelerated life testing to determine which defect levels form or are activated, and how they impact the static and dynamic HEMT performance. The primary static changes were a negative shift of the threshold voltage and an increase in knee walkout/on-resistance. The primary dynamic effect of the stressing appeared in the form of a time-dependent increase in the on-resistance, and this was found to correlate to first order with formation and/or activation of traps at Ec-0.57 and Ec-0.72 eV traps that contributed to the dynamic changes, and the Ec-1.5 eV trap was likely responsible for the static change in on-resistance. Trapping kinetics analysis revealed that the physical sources for the EC-0.57 and EC-0.72 eV states are not simple, ideal, non-interacting point defects, but instead are associated with physically extended defects, such as dislocations, and/or defect complexes.