Physical basis for nondestructive tests of MOS radiation hardness

It was found that the 1/f noise and channel resistance of unirradiated nMOS transistors from a single lot with various gate-oxide splits closely correlate with the oxide-trap and interface trap charge, respectively, following irradiation. The 1/f noise is explained by scattering from interface-trap precursor defects. It appears that both noise and channel mobility measurements may be useful in defining nondestructive hardness assurance test methods for devices fabricated from a single technology. It may be difficult to use either for making cross-technology comparisons. It was found that process techniques that improve the radiation hardness of MOS devices at room temperature can greatly reduce the 1/f noise of MOS devices at cryogenic temperatures.>