Radiation tolerance of III-V compound semiconductor devices (GaAs MESFET)

The effects of gamma-ray irradiation on the electrical characteristics of commercial 0.5-μm gate low-noise GaAs MESFET have been investigated. Changes in DC electrical parameters (VP, IDSS, gm), microwave scattering parameters (S parameters) and minimum noise figure (NFmin) were measured at gamma-ray doses up to 8 x 108 rads (GaAs). Below the irradiation of 8 x 107 rads (GaAs), there was no measurable change in DC characteristics, except small changes in minimum noise figure (NFmin) between 8 x 106 and 8 x 107 rads (GaAs). The change is not considered to be a limitation since it occurred within the recommended DC parameters and NFmin of operation of the device. The change in electrical characteristics of a GaAs MESFET as a function of gamma-ray dose is caused mainly by a decrease in effective carrier concentration in an active layer. These radiation induced changes in parameters are described. (author)