Radiation-induced resistance changes in TaOx and TiO2 memristors

TaO_x and TiO₂ memristors have been irradiated with 800 keV Ta ions, 28 MeV Si ions, and 10 keV X-rays. TaO_x devices were also irradiated with 70 keV electrons. Displacement damage effects are studied using 800 keV Ta ions and both technologies show changes in resistance for fluences greater than 10¹⁰ cm^-2. TaO_x devices show gradual resistance degradation in the off-state with increasing fluence. TiO₂ devices show gradual inconsistent increases in off-state resistance with inconsistent abrupt decreases. TaO_x devices show more stability and consistent off-state resistances than TiO₂ devices. Ionization effects are investigated using 28 MeV Si ions, 70 keV electrons, and 10 keV X-rays. During 28 MeV Si irradiation, both technologies change from the off-state to the on-state when a critical ionizing dose is reached without applying voltage or current to the device. The critical threshold is calculated using SRIM to be on the order of 60 Mrad(Si) or higher. 10 keV X-ray irradiation of doses up to 18 Mrad(Si) per step show little effect on either technology. A single TaO_x device irradiated with 70 keV electrons changed from the offstate to the on-state at a calculated dose on the order of 100 krad(Si), suggesting a difference in charge yield compared to the 28 MeV Si irradiation.