Characterization of Deep and Shallow Traps in GaN HEMT Using Multi-Frequency C-V Measurement and Pulse-Mode Voltage Stress

Thermal effect on dynamic R_on degradation of p-GaN AlGaN/GaN HEMTs on SiC substrates

“…Compare to the significant impact on dynamic R on degradation from off-state drain voltage, the increased amplify from the increased on-state gate voltage is much less. As previously studied [12], the surface traps ionized from on-state gate voltage play an important role in the dynamic R on degradation. The results also imply the trap mechanisms induced by the on-state gate voltage is self- heating dependent.…”

“…High-field mobility saturation model and inverse piezoelectric effect are adjusted to improve the simulation accuracy and consistent with the real situation. The polarization scale parameter with 0.29 has been applied to be consistent with the measured experimental data [12]. Shockley-Read-Hall and Fermi-Dirac statistics are enabled to simulate the trapping and de-trapping mechanisms under different voltage stresses [25,26].…”

“…And as the SiC has higher thermal conduction compare to Si, the GaN buffer layer in the GaN-on-SiC HEMTs will suffer lower temperatures under the same operating conditions [22]. The lower temperature in GaN buffer will trigger less ionized acceptor-like traps, where the hole-emission from the ionized acceptor-like traps will deplete the 2DEG with decreased dynamic R on degradation in GaN-on-SiC HEMTs [12].…”

“…A p-type doped GaN layer is covered locally under the gate in order to achieve enough high threshold voltage with a low specific on-resistance [6,7,8,9,10]. However, the capabilities of a full integrated GaN power electronics are still limited by several reliability issues when GaN HEMTs are operated between kHz to MHz switching frequencies [11,12,13,14,15,16].…”

“…On the one hand, several trapping mechanisms responsible for dynamic R on degradation have been investigated, relating to surface hot electron injection and buffer traps mechanisms [12,14]. These traps can be generated in a variety of ways, starting from the epitaxy with lattice defects like vacancies, dislocations, or impurities.…”