In this paper, the electrical characteristics of GaN HEMT devices before and after RF overstress have been investigated. The experimental results show that the drain current of GaN HEMT decreases by 35.6% from 877 mA to 564mA after RF overstress. Moreover, after the experiment, the threshold voltage has a 0.26-V positive shift, and the maximum transconductance decreases. The gate-to-source current and gate-to-drain current increases by three times more than that of fresh ones. The gate-lag characteristics also deteriorates with the increase of experimental time. After measuring the high frequency performance, the return loss of the device degrades. Based on the measurement of leakage current, the height of Schottky barrier before and after the experiment was calculated and the captured charge density was extracted as 1.11×10¹⁴ cm^-2 by combining with the threshold voltage drift.

high electron mobility transistor (HEMT),Gallium nitride (GaN),Radio frequency (RF)