Effect of proton irradiation energy on SiN_x/AlGaN/GaN metal-insulator semiconductor high electron mobility transistors

The effects of proton irradiation energy on the electrical properties of SiN_x/AlGaN/GaN metal-insulator semiconductor high electron mobility transistors (MISHEMTs) using in situ grown silicon nitride as the gate dielectric were studied. The SiN_x/AlGaN/GaN MISHEMT devices were irradiated with protons at energies of 5, 10, or 15 MeV at a fixed fluence of 2.5 × 10¹⁴ cm⁻². The largest amount of device degradation was shown in the samples irradiated with the lowest irradiation energy of 5 MeV. The DC saturation current was reduced by 10.4%, 3.2%, and 0.5% for MISHEMTs irradiated with proton energies of 5, 10, and 15 MeV, respectively. Device performance degradation was more pronounced in the irradiated samples under high-frequency operation. At a frequency of 100 kHz, the percent saturation drain current reduction at a gate voltage of 3 V was 40%, 19%, and 17% after proton irradiation at 5, 10, and 15 MeV, respectively. The carrier removal rates for the MISHEMT devices were in the range of 21-144 cm⁻¹ for the proton irradiation energies studied. The measured DC degradation and carrier removal rates are lower than the values reported for AlGaN/GaN metal-gate high electron mobility transistor devices irradiated at similar conditions, which can be attributed to the SiN_x insulating layer reducing the total damage on the AlGaN surface.