Impact of TID on the Transient Ionizing Irradiation Response of CMOS Circuits

Total ionizing dose (TID) can cause the threshold voltage of complementary metal oxide semiconductor (CMOS) transistors to shift backward and the current gain of the parasitic triode to degrade; these two factors will compete while devices accumulating TID expose to transient ionizing irradiation, and the data status depends on the dominant one. Micrometer (CD4007) and sub-micrometer (IDT71256) CMOS devices were investigated on the synergistic effects of TID and transient ionizing irradiation. The results reveal that the current gain degradation induced by TID, for CD4007, plays a significant role; whereas the shrink of the static noise margin (SNM) induced by TID, for IDT71256, is the dominant factor and the influence of the parasitic transistor can be ignored. The reasons are sub-micrometer devices have the thinner gate oxide, resulting in the current gain degradation induced by TID not evident; and the collection volume of photocurrent is too small to generate enough primary photocurrent for driving the parasitic transistor on. In sum, the synergistic effects of TID and transient ionizing irradiation are evident in large-scale devices, while not evident in small-scale devices.