X-Ray and Proton Radiation Effects on 40 nm CMOS Physically Unclonable Function Devices

Total ionizing dose effects are investigated on a physically unclonable function (PUF) based on CMOS breakdown. Devices irradiated to 2 Mrad(SiO2) show less than 11% change in current ratio at 1.2 V. The read-out window of programmed PUFs decreases significantly at high-dose proton irradiation, and then recovers back to the original value after annealing. The proton test results for the pFET selector, the unbrokennFET, and the brokennFET indicate that the threshold-voltage shift of the pFET selector contributes mainly to the degradation of the PUF.