Superior TID Hardness in TiN/HfO$_{2}$/TiN ReRAMs After Proton Radiation

Abstract

Resistive switching properties of valence change memory (VCM) resistive-random-access-memory (ReRAM) devices (TiN/HfO2 /TiN) are investigated after exposure to proton radiation with total ionizing doses (TID) of 1.5, 3, and 5 Grad(Si) and compared to similar measurements from electrochemical metallization memory (ECM) ReRAM devices (Pt/HfO2:Cu/Cu). The TiN/HfO2/TiN ReRAMs show significantly superior TID radiation-hardness compared to Pt/HfO2:Cu/Cu ReRAMs: 1) All devices remained functional after radiation; 2) switching parameters including average Vset, Vreset, Ron, Roff showed minimal or no degradation; and 3) TID radiation enhanced the uniformity of resistive switching among all VCM devices. The superior radiation responses of the VCM ReRAM devices relative to ECM ReRAMs result from the distinct conduction filament (CF) formation mechanisms. For the VCM ReRAM system, the radiation-induced vacancy density does not serve to inhibit the trap-assisted tunneling associated with the Hf-rich CF formation kinetics. On the contrary, vacancy-promoted charge trapping promotes VCM CF stability. In strong contrast, proton-induced vacancies for the ECM ReRAMs inhibit the formation of the metallic filament through internal field reduction due to charge trapping. The comparison of TID effects suggests that HfO2-based VCM ReRAMs can be made radiation immune to a TID up to 5 Grad(Si) and may be highly suitable for rad-hard electronics applications.