Effect of Proton Irradiation Energy on AlGaN/GaN HEMTs fabricated by Ion-implanted Isolation

We evaluated the effect of the proton irradiation energy on electrical properties of AlGaN/GaN high electron mobility transistors (HEMTs) fabricated by Ar + ion-implanted isolation. The HEMTs were exposed to various irradiation energies - 0.5 MeV, 5 MeV, and 60 MeV, respectively, with a fluence of $1\times 10^{14}$ p/cm2, at room temperature. The proton radiation-induced degradation of HEMTs was occurred by the displacement damage effect, which is directly related to the nonionizing energy loss (NIEL). The saturation drain current of 0.5 MeV-irradiated HEMT has more severely degraded than that of 60 MeV-irradiated HEMT because the lower proton energy has the larger NIEL. The threshold voltage of HEMTs with proton irradiation is usually positively shifted due to the reduction of 2-dimensional electron gas (2DEG) density by defects created during irradiation, however, the 60 MeV-irradiated HEMT showed the negative threshold voltage shift, which is discrepant from reported results.