On-wafer RF stress and trapping kinetics of Fe-doped AlGaN/GaN HEMTs

In this paper, we investigate the trapping effects, of iron doped AlGaN/GaN HEMTs, before and after on-wafer 24 hour RF stress test. First, we study the trap centers responsible of the current collapse at different on-state bias and temperature conditions. Second, we investigate 24 hour RF stress effect on the trapping kinetics. By filling traps under off-state condition with high drain-source voltage, we have identified two prominent traps labelled E-1 and E-2 with activation energies of 0.7 eV and 0.6 eV under the conduction band, respectively. An increase of the amplitude of the trap centers E-1 and E-2 by 22.9% and 15.8% respectively is noticed during the RF stress. This result suggests that the degradation observed during RF stress might have induced a density increase of the traps involved in the E-1 and E-2 trap signatures responsible on the current collapse.