Effects of neutron irradiation on the noise of junction field-effect transistors

A study is presented of the electrical noise properties of junction field-effect transistors subjected to neutron irradiation. Selected devices were exposed to both fast and thermal neutrons in the University of Florida Training Reactor. It is shown that such irradiation gives rise to a number of defects both in the channel and in the depletion layer of the gate-channel junction. The noise spectra of irradiated devices exhibit much structure due to the generation-recombination involving these defects. From measurements down to cryogenic temperatures, the lifetimes and activation energies of the defects could be deduced. The noise spectra are interpreted with the aid of a modified theory concerning depletion layer generation-recombination noise. Other types of noise theory, pertaining to channel defects are also considered. From the energy levels of the defects and the effects of annealing temperature on the noise, information was obtained to classify and identify some of the defect centers