Effect of Frequency on Total Ionizing Dose Response of Ring Oscillator Circuits at the 7-nm Bulk FinFET Node

Total ionizing dose (TID) effects at the 7-nm bulk FinFET node are characterized under dynamic and static test conditions through changes in ring oscillator (RO) frequencies, leakage currents, and inverter delays. Results from total-dose exposures using the ARACOR X-ray machine showed that static conditions represented the worst case conditions. Higher operating frequencies resulted in increased leakage currents and inverter delays after irradiation. The rate of change for leakage current was inversely proportional to frequency during exposure. The rate of change for inverter delay was directly related to frequency during TID exposure. Overall, degradations in circuit-level parameters (logic gate delays and operating current) were less than 1% for TID exposures of 435 krad(SiO
₂
).