Al-doping engineered electroforming and switching dynamics of TiO_x ReRAM devices

TiO2 thin films have drawn a lot of attention for their application in emerging memory devices, such as resistive random access memory (ReRAM). However, TiO2 ReRAM still faces reliability issues, including poor endurance, large device-to-device and cycle-to-cycle variability of switching parameters and low yields. Moreover, high electroforming voltages have been often associated with irreversible damage to devices. Doping of TiO2 has been employed as a strategy for overcoming these issues. Therefore in this work, we used Al as a dopant in TiO2 thin films to investigate its effect on electroforming and switching voltages of ReRAM devices. Conductive atomic force microscopy (C-AFM) measurements on these thin films, suggested that Al doping decreased the switching voltages compared to the undoped thin films. This result was confirmed by pulse voltage sweeping of ReRAM devices employing the same doped thin films. The Al-doped devices were on average electroforming at -5.7 V, compared to -6.4 V for the undoped ones, and they were switching with potentials as low as ±0.9 V. These findings suggest a potential pathway for implementing low-power ReRAM systems