Effects of 2 MeV Ge irradiation on AlGaN/GaN high electron mobility transistors

The dc characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) were measured before and after irradiation with 2 MeV Ge ions at doses from 5 × 1010 to 5 × 1012 cm-2. The drain current, gate leakage current, and transconductance decreased monotonically with dose, while the drain-source resistance increased to a much greater extent than observed previously for proton irradiation of similar devices. The data are consistent with a strong decrease in electron concentration in the HEMT channel. During off-state electrical stressing of AlGaN/GaN HEMTs, the typical critical voltage for unirradiated devices was ∼13 V. By sharp contrast, no critical voltage was detected for proton irradiated HEMTs up to 35 V, indicating that the Ge irradiation had a strong influence on the electric field distribution near the gate electrode. © 2013 American Vacuum Society.