Investigation on the Degradation Mechanism of A1GaN/GaN HEMTs Under the Effect of Microwave Pulses at Different Powers

We have investigated the effect of microwave pulse stress of different powers on A1GaN/GaN HEMTs. The dc characteristics of the devices were first scrutinized. The results indicate that the electrical characteristics of the devices are degraded after stress. The saturation drain-source current decreases from 681.8 mA to 246.5 mA, a decrease of 63.8 63.8%, at the power 40 dBm. And at the power 45 dBm, the saturation drain-source current drops even more, from 662.3 mA to 176.7 mA, a drop of 73.3 73.3%. The stress results in significant positive drift of threshold voltage and decrease of gate leakage current. And the degradation is more obvious with increasing microwave pulses power. Then, the internal defects of the device are characterized by low-frequency noise method, and the mechanism of device degradation is discussed. At the power of 45 dBm, the internal defect density of the device doubles, resulting in more electrons being captured at the channel. This is useful for the reliability level of future devices and practical applications.