Influence of Hot Carrier Degradation on Total Ionizing Dose in Bulk I/O-FinFETs

Electronic components operating in aerospace environments face a variety of reliability issues. The total ionization dose (TID) degradation mechanism of bulk I/O-FinFETs and the influence of hot carrier degradation (HCD) on TID irradiation are investigated in this paper. Devices under ON/TG/OFF bias conditions were irradiated to 2 Mrad (Si). The nFinFETs show degradation of threshold voltage, subthreshold swing and off-state leakage current. An increase in peak transconductance and on-state current was also observed in the nFinFETs. The TID response of nFinFETs is dominated by positively trapped charges in the gate oxide and shallow trench isolation (STI). For pFinFETs, radiation-induced hole-trapped charges leads to an increase in the threshold voltage and a decrease in the drive current. The worst degradation is observed when a high electric field is applied to the gate during irradiation. Post-stress irradiation results show that the HCD and TID degradation trends of the nFinFETs are opposite and have a mutual canceling effect, while the degradation trends of the pFinFETs are consistent and jointly deteriorate the device performance. Compared to the un-stressed devices, the TID damage of the pre-stressed devices is more drastic, especially for the nFinFETs. The stress-induced interface trapped charges increase the electric field in the gate oxide during subsequent irradiation, which causes more radiation-induced hole-trapped charges and exacerbate TID degradation.