Radiation-induced resistance changes in TaOx and TiO2 memristors

TaO
_x
and TiO
₂
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 10
¹⁰
cm
^-2
. TaO
_x
devices show gradual resistance degradation in the off-state with increasing fluence. TiO
₂
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 TiO
₂
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.