dc and rf performance of proton-irradiated AlGaN/GaN high electron mobility transistors

AlGaN/GaN high electron mobility transistors (HEMTs) with a range of gate l engths (0.8-1.2 mum) and widths (100-200 mum) were exposed to 40 MeV proton s at fluences of 5x10(9) or 5x10(10) cm(-2). The drain-source currents in t he devices decreased by 15%-20% at the higher fluence, while the extrinsic transconductance decreased by similar to 30% under the same conditions. Bas ed on the increases in the reverse breakdown voltage and the channel resist ance, the main degradation mechanism is believed to be creation of deep tra p states in the band gap which remove electrons from the channel. The maxim um frequency of oscillation, f(MAX), also decreased as a result of the prot on-induced damage, with a change of -20% at the shorter gate widths and -50 % at the largest widths. The reverse recovery switching time was essentiall y unaffected by the irradiation, remaining at similar to1.6x10(-8) s. Postr adiation annealing at 800 degreesC was successful in restoring the dc and r f performance parameters to greater than or equal to 90% of their original values. The AlGaN/GaN HEMTs are much more robust than their AlGaAs/GaAs cou nterparts to displacement damage and appear well-suited to radiation enviro nment applications. (C) 2001 American Institute of Physics.