Self-Modulating Interfacial Cation Migration Induced Threshold Switching in Bilayer Oxide Memristive Device

A selector device based on threshold switching is a potential candidate for preventing leaky current from nearby units in cross-point memristor arrays during operation, which is required for low-cost operation and good reliability. A simple selector structure, i.e., Ag/HfOy/HfOx/Pt (AHHP), was constructed in this work. The device exhibits electroforming-free properties, a low threshold switching voltage of ∼0.28 V, a wide range of operating current from 1 nA to 300 μA, and an extremely sharp switching slope of ∼0.6 mV/dec. Both selector and memristor can be achieved by simple and compatible technology in comparison with a memristor structure of Ag/HfOx/Pt. In light of the detailed microstructure characteristics, a coupling mechanism between crystallite kinetics and activated Ag atom migration in the electrolyte is presented and discussed in detail. Stress-assisted crystallite rotation of hafnium oxide in AHHP interferes with the bonding and evolution feature of Ag conductive filaments and then induces sel...