Increased Device Variability Induced by Total Ionizing Dose in 16-nm Bulk nFinFETs

This article investigates the device variability induced by the total ionizing dose (TID) effects in a commercial 16-nm bulk nFinFETs, using specially designed test structures and measurement procedures aimed at maximizing the matching between devices. DC static characteristic measurements show that below 100 Mrad(SiO ₂ ) the device variability is slightly affected by the total accumulated dose. However, when the total dose reaches 100 Mrad(SiO ₂ ), the device variability increases significantly showing a correlation with pre-irradiation electrical responses of the devices. Transistors characterized by higher drain current exhibit the worst TID degradation. This phenomenon is likely due to the impact of random dopant fluctuations on the TID effects and/or to variations in the hydrogen concentration responsible for the TID-induced interface traps.