Low-power TiN/Al2O3/Pt resistive switching device with sub-20 μA switching current and gradual resistance modulation

Resistive-switching random access memory (RRAM) using the TiN/AlOx/Pt stack is fabricated with a 50 nm x 50 nm active area. The bipolar switching characteristic is observed using TiN as an anode and RESET current as low as sub-20 mu A was achieved by using a current-limiting transistor as a selection device (1T1R) during the SET process. HRS to LRS ratio of 10(3) for 10(3) DC endurance test cycles is demonstrated. Switching time less than 10 ns was observed for both SET/RESET operations. By changing the gate bias of the series transistor and input voltage at the transistor drain terminal, multi-level resistance states can be modulated. Both the unipolar and bipolar resistance switching can coexist in such memory stacks and a qualitative model is proposed for the AlOx-based RRAM resistive switching behavior. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3657938]