Effect of Small-Molecule Layer Thickness on Nonvolatile Memory Characteristics for Small-Molecule Memory-cells

Abstract

We investigated the effect of small-molecule layer thickness on nonvolatile memory characteristics such as memory margin, retention-time, and multi-level memory-cell operation for cross-bar 4F(2) small-molecule memory-cells embedded with Ni nanocrsystals surrounded by a NiO tunneling barrier. For a 50-nm small-molecule layer, the memory-cell demonstrated a memory margin of similar to 7.02 x 10(3) and a retention-time of similar to 10(5) s at 85 degrees C for four current levels. However, these nonvolatile memory characteristics worsened when the small-molecule layer thickness increased above 50-nm, and they eventually disappeared at similar to 140-nm. This is related to current conduction mechanisms, such as space-charge-limited-current and thermionic-field-emission-current, which depend on small-molecule layer thickness.