Degradation and recovery of AlGaAs/GaAs p-HEMT irradiated by high-energy particle

Results of an extensive study on the irradiation damage and its recovery be havior resulting from thermal annealing in AlGaAs/GaAs pseudomorphic high e lectron mobility transistors (HEMTs) subjected to a 220-MeV carbon, 1-MeV e lectrons and 1-MeV fast neutrons are presented. The drain current and effec tive mobility decrease after irradiation, while the threshold voltage incre ases in positive direction, The decrease of the drain current and mobility is thought to be due to the scattering of channel electrons with the induce d lattice defects and also to the decrease of the electron density in the t wo dimensional electron gas region. Isochronal thermal annealing shows that the device performance degraded by the irradiation recovers. The decreased drain current for output characteristics recovers by 75% of pre-rad value after 300 degreesC thermal annealing for AlGaAs HEMTs irradiated by carbon particles with a fluence of 1 x 10(12) cm(-2) The influence of the material s and radiation source on the degradation is also discussed with respect to the nonionizing energy loss. Those are mainly attributed to the difference of particle mass and the probability of nuclear collision for the formatio n of lattice defect in Si-doped AlGaAs donor layer. A comparison is also ma de with results obtained on irradiated InGaP/InGaAs p-HEMTs in order to inv estigate the effect of the constituent atom. The damage coefficient of AlGa As HEMTs is also about one order greater than that of InGaP HEMTs for the s ame radiation source. The materials and radiation source dependence of perf ormance degradation is mainly thought to be attributed to the difference of mass and the possibility of nuclear collision for the formation of lattice defects in Si-doped donor layer. (C) 2001 Elsevier Science Ltd. All rights reserved.