Small-Molecule Nonvolatile Memory Cells Embedded with Ti Nanocrystals Surrounded by TiO2 Tunneling Barrier

Abstract

We developed cross-bar 4F(2) small-molecule nonvolatile memory-cells embedded with Ti nanocrystals surrounded by a TiO2 tunneling barrier. The Ti nanocrystals size and distribution were primarily determined by the Ti layer evaporation rate followed by in-situ O-2-plasma oxidation; i.e., the size increased with the evaporation rate and the size uniformity of Ti nanocrystals became better as the evaporation rate increased from 0.1-2.0 angstrom/s, then became worse as the evaporation rate increased above 2.0 angstrom/s. At a specific evaporation rate, small-molecule memory-cells embedded with Ti nanocrystals demonstrated typical nonvolatile memory characteristics, such as symmetrical current vs voltage (I-V) characteristics, I-on/I-off ratio of 4.2 x 10(2), stable retention time, and program/erase cycles.