Cluster-Type Filaments Induced by Doping in Low-Operation-Current Conductive Bridge Random Access Memory.

Abstract

Conductive bridge random access memory (CBRAM) is one of the most representative emerging nonvolatile memories in virtue of its excellent performance on speed, high-density integration, and power efficiency. Resistive switching behaviors in CBRAM involving the formation/rupture of metallic conductive filaments are dominated by cation migration and redox processes. It is all in the pursuit to decrease the operation current for low-power consumption and to enhance the current compliance-dependent reliability. Here, we propose a novel structure of Pt/TaOx:Ag/TaOx/Pt with nonvolatile switching at ∼1 μA and achieve a five-resistance-state multilevel cell operation under different compliance currents. Different from the nanocone-shaped filaments reported in traditional Ag top electrode devices, cluster-type filaments were captured in our memory devices, explaining the low-operation current-resistive switching behaviors. Meanwhile, Cu-doped counterpart devices also display similar operations. Such memory devices are more inclined to achieve low-power consumption and offer feasibility to large-scale memory crossbar integration.