Total Ionizing Dose Effects in Si-Based Tunnel FETs

Total ionizing dose (TID) effects in Si-based tunnel finite element transfers (FETs) were investigated for the first time. Under 10-keV X-ray irradiation environment, along with the increase in total dose, a shift of the transfer characteristics and an increase in the interface trap density could be observed. After irradiation at 1 Mrad (SiO₂) (and higher dose), the threshold voltage and the band-to-band tunneling conduction were only modestly affected, despite the thick buried oxide (140 nm). In contrast, under the same bias and irradiation environment, a FDSOI nMOSFET fabricated with a similar process presented a more severe degradation, suggesting the robustness of TFETs against TID effects. The underlying mechanism was explored through device simulation and ascribed to be due to the peculiarity of the doping structures of TFETs.