Universal-ion irradiation dose threshold and error recovery in HfO2 resistance random access memory

Resistive random access memory (ReRAM) is an attractive candidate for application in next-generation nonvolatile (NV) memory devices for both aerospace and conventional commercial applications. ReRAM has several intrinsic advantages over other NV memory technologies due its simple metal-insulator-metal structure including high storage density, low power consumption, high switching speed and high endurance. Most importantly, there are indications that ReRAM is an intrinsically radiation-hard device due to its defect-moderated, resistive switching mechanism and potentially well suited for applications in aerospace or other radiation intensive environments. We present a study of the effects of ion irradiation on HfO₂-based ReRAM devices after irradiation to total ionizing doses ranging from ~ 10⁵ to ~ 10¹¹ rad(Si), with various ion species - proton, helium, nitrogen, neon, and argon. HfO₂-based ReRAM devises were programmed into high resistance states (HRS, off states) and low resistance states (LRS, on states) before radiation exposure. It was found that static off- and on- state resistances decreased dramatically when the total ionizing dose is above a threshold value ~ 1 × 10¹⁰ rad(Si), independent of the ion specie. Moreover, more than 50% of off-state devices changed into the on-state above this threshold dose, causing errors in resistance state. However, ALL switching errors were shown to be correctable via a programmed RESET process, after which all ReRAM devices resumed normal resistive switching function with only slight variations in set/reset voltages and dynamic on-/off-state resistances. The universal dose behavior is consistent with recent modeling of ReRAM conductive filament formation via trap-assisted-tunneling (TAT) and thermal runaway of oxygen vacancy defect formation. Overall, this study suggests that, for HfO₂-based ReRAMs, a universal dose threshold behavior associated wit- ion irradiation can be used to predict irradiation-induced soft errors in resistance state switching and can be used for HfO₂-ReRAM application design in space systems.