Effects of AlGaN/GaN HEMT structure on RF reliability

A comparison of RF reliability at 10 GHz on four different undoped AlGaN/GaN HEMT structures with AlGaN barrier thickness variation is presented. The output power degradation characteristics during RF stress for each structure are shown, and the results indicate a strong dependence of reliability on AlGaN thickness. A device from the structure with the thinnest AlGaN in the study, with initial output power of 8.8 W/mm at 40 V, showed only a change of 0.55 dB in output power after 185 h of RF stress at 40 V. The results demonstrate excellent RF reliability of high-power devices and the potential of stable high-power operation of undoped AlGaN/GaN HEMTs on SiC.