Stability of Nitride Microwave Monolytic ICs of a Signal Converter Irradiated by Neutrons and Gamma Radiation

The radiation stability of AlGaN/GaN HEMT millimeter-wave signal converters with highly mobile electrons irradiated by neutron and gamma radiation is investigated. The following characteristics have been chosen as the parameters for estimating the stability: the output microwave signal range, conversion factor, and the total consumed current. The consumed current dependence on the absorbed dose of gamma radiation and the sample temperature is determined. It is shown that the effect of neutron irradiation upon the characteristics is insignificant, although the gamma irradiation results in a considerable increase of the current consumed due to the formation of nitrogen donor vacancies, annealing of growth acceptor defects, and defect ordering. Six months later, the parameters of the devices returned to the initial values, indicating the restoration of the original state of the substrate’s crystal structure.