Pt/Al2O3/TaO X /Ta Self-Rectifying Memristor With Record-Low Operation Current (<2 pA), Low Power (fJ), and High Scalability

Self-rectifying memristor (SRM) with high rectification ratio (RR) and nonlinearity (NL) is a superior candidate for 3-D integrated array by effectively tackling the sneak path problem. In this article, we fabricated bilayer Pt/Al₂O₃/TaO $_{\!{X}}$ /Ta SRMs with a 250-nm feature size, which show record-low < 2-pA operation current, >10³ ON-/ OFF-ratio, >10⁴ RR, high uniformity, and good retention. The high resistance [low resistance state (LRS): 10¹⁰– $10^{11} \Omega $ , high resistance state (HRS): > $10^{14} \Omega $ ] yields fJ-level switching power consumption. Moreover, the SRMs exhibit superior NL (~10⁴) and ultralow leakage current (~10 fA), leading to a calculated 538-Mbit passive array scalability with the premise of 10% read margin. Detailed mechanism analysis reveals that high RR and NL can be attributed to the high barrier in Pt/Al₂O₃ and Al₂O₃/TaO $_{\!{X}}$ interface, respectively, during the resistive switching process. Our work advances the development of SRMs for high-density passive array and even 3-D integration.