Generation of traps in AlGaN/GaN HEMTs during RF-and DC-stress test

The effect of RF stress at 10 GHz and DC stress on AlGaN/GaN HEMTs have been investigated by comparing static and transient characteristics before and after stress. It was found that the threshold voltage shifts in both tests significantly to the negative. A defect level of 0.44 eV was detected during Id-trapping analysis. Using the experimental trap data and simulating different locations of traps in the device it was established that the defective region is extended throughout the gate region. Quantitative approximations of the trap density suggest an extension of the traps into the barrier layer with a concentration of approximately 10¹⁸ cm^-3.