Self-Selection RRAM Cell With Sub- $\mu \text{A}$ Switching Current and Robust Reliability Fabricated by High- $K$ /Metal Gate CMOS Compatible Technology

A high-K/metal gate (HKMG)-stack (TiN/Al-dopedHfO
_x
/SiO
₂
/Si)-based bipolar resistive random access memory (RRAM) cell is proposed and fabricated by 28/20-nm HKMG CMOS compatible technology. Robust reliability behaviors (retention at 200°C 4 × 10
⁴
s and endurance 10
⁵
cycles) and ultralow switching current (<;0.1 μA for RESET and <;0.3 μA for SET) are both demonstrated. The sub-μA switching current and self-selection nonlinear I-V characteristics are attributed to the SiO
₂
interfacial layer rather than the decrease of conductive filament size and oxygen vacancy (VO) density, which can be verified by HRTEM and measured conduction behavior. Therefore, robust reliability property is also achieved. The demonstrated excellent memory characteristics of HKMG stacked RRAM cell enable constituting 1-Mb workable crosspoint array even though the feature size scales down to 10 nm according to the HSPICE simulation.