Heavy ion total fluence effects in GaAs devices

Heavy ion radiation effects were studied in GaAs FETs, monolithic microwave integrated circuits (MMICs), and high-electron-mobility transistors (HEMTs). Degradation of GaAs FETs, MMICs, and HEMTs occurred at about 10/sup 9/ cm/sup -2/ for 14.5-MeV Si and at 10/sup 12/ cm/sup -2/ for 2-MeV protons. Carrier removal resulting from displacement damage in the active channel, or in the doping layer in the case of HEMTs, is the primary reason for the decrease in drain current and gain and the increase in noise figure. Decrease in mobility is also a contributing factor. HEMTs were found to degrade in gain and noise figure at higher levels of irradiation, primarily because of the initial higher dopant concentration in the AlGaAs N/sup +/ doping layer.<
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