In-situ nanoscale characterization of annealing effect on TiN/Ti/HfOx/TiN Structure for Resistive Random Access Memory (ReRAM)

In order to provide resistive switching functionality to a TiN/Ti/HfO
_x
/TiN structure, a high-temperature annealing process is required. In this paper, the influence of the annealing effect on the TiN/Ti/HfO
_x
/TiN structure was analyzed by the transmission electron microscopy (TEM) under the elevated temperature. From the electron energy loss spectroscopy (EELS) measurements, it was clarified that the lateral distribution of Oxygen at the nanoscale region near the Ti/HfO
_x
interface was modulated at 400°C, while that of Titanium was almost unchanged. The influence of the PDA process on the resistive switching characteristics was also evaluated. An adequately reduced virgin state with Oxygen accumulated in electrode material is thought to be a key structure for the resistive switching.