Improved Resistive Switching Characteristics of NiO Resistance Random-Access Memory Using Post-Plasma-Oxidation Process

A practical approach to oxygen compensation is investigated to improve a resistive change characteristic of NiO films. The stoichiometry of a physical vapor deposited NiO (PVD-NiO) is changed by post-plasma-oxidation (PPO) process at 350 °C. The PPO process eliminates oxygen vacancies and compensates for a loss of oxygen during Cu back-end-of-line (BEOL) process, which results in a lower forming voltage and a higher OFF/ON resistance ratio. The PPO also improves the surface roughness of the PVD-NiO film, reducing a cell-to-cell variation of the forming voltage. The developed NiO resistance random-access memory (ReRAM) integrated in Cu-BEOL coupled with the PPO process is applicable for realizing a low-power and stable resistive switch.