Proton Irradiation Effects on AlGaN/GaN HEMTs With Different Isolation Methods

We evaluated the electrical characteristics of two different AlGaN/GaN high-electron mobility transistors (HEMTs) for the 5-MeV proton irradiation effects. The difference of the HEMTs originates from the isolation methods, such as mesa etching and nitrogen ion implantation. At a proton fluence of $1 \times 10^{14}$ p/cm2, the saturation drain currents of two devices are reduced by 50% and 11% for the mesa etching and the nitrogen ion implantation, respectively. The displacement damages are believed to degrade the electrical characteristics of AlGaN/GaN HEMTs. AlGaN/GaN HEMTs with nitrogen ion implantation isolation show relatively higher radiation hardness than those with mesa etching isolation. The reason is that plasma etching easily damages the surface of mesa sidewall and causes more defects by proton irradiation.