Radiation Effects on GaAs MESFETs

The effect of fast neutron and gamma radiation on the electrical characteristics of commercial 1 μm and 4 μm low noise GaAs MESFET has been evaluated. The change in the microwave scattering parameters at 2 to 4 GHz (S-band), 1 MHz equivalent circuit parameters, DC characteristics and low frequency input noise equivalent voltage from 2 KHz to 1.5 MHz was determined at neutron fluences between 5 × 1013 to 8 × 1014 n/cm2 and gamma doses of up to 8 × 107 rads (Si). These radiation induced changes are described and causes for these changes are discussed.