We have demonstrated resistance switching using HfO2 film with a Cu top electrode for nonvolatile memory applications, and revealed the Cu diffusion into the HfO2 layer during the filament formation process. Resistive switching was clearly observed in the Cu/HfO2/Pt structure by performing current-voltage measurements. The current step from a high resistive state to a low resistive state was of the order of 103-104 Ω, which provided a sufficient on/off ratio for use as a switching device. The filament formation process was investigated by employing hard x-ray photoelectron spectroscopy under bias operation. The application of a bias to the structure reduced the Cu2O state at the interface and the intensity ratio of Cu 2p3/2/Hf 3d5/2, providing evidence of Cu2O reduction and Cu diffusion into the HfO2 layer. These results also provide evidence that the resistance switching of the Cu/HfO2/Pt structure originates in a solid electrolyte (nanoionics model) containing Cu ions.
|Number of pages||10|
|Publication status||Published - 2014 Jan 1|
|Event||6th International Symposium on Dielectrics for Nanosystems: Materials Science, Processing, Reliability and Manufacturing - 225th ECS Meeting - Orlando, United States|
Duration: 2014 May 11 → 2014 May 15
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