Statistical investigation of the impact of program history and oxide-metal interface on OxRRAM retention

We statistically investigate for the first time the impact of programming history on the data-retention properties of tail bits in scaled OxRRAM devices. By using an innovative test method we demonstrate for a same cell that retention is not only affected by programming pulse duration but also by pre-Write pulse-pattern and delay between pulses. This approach, combined with material engineering exercise, allowed to clarify the role of oxide-metal interface and oxygen chemical potential profile along filament in improving data stability. Based on these learnings, a TaOx-based stack is proposed for embedded application, showing great retention with immunity to BEOL thermal stress.