Bias induced Cu ion migration behavior in resistive change memory structure observed by hard X-ray photoelectron spectroscopy

Takahiro Nagata, Yoshiyuki Yamashita, Hideki Yoshikawa, Masataka Imura, Seungjun Oh, Kazuyoshi Kobashi, Toyohiro Chikyow

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The Cu ion migration behavior of a Pt/Cu/HfO2/Pt structure, which is an oxide-based resistive random access memory (ReRAM) and exhibits resistance switching behavior at voltages of ±0.8 V, was investigated by hard X-ray photoelectron spectroscopy under a bias operation. A forward bias application, during switching from a high resistive state (HRS) to a low resistive state, reduced the Cu2O bonding state at the interface and the intensity ratio of Cu 2p3/2/Hf 3d5/2 (Cu/Hf) by 23 ± 5%, providing evidence of reductions in unintentionally formed Cu2O and Cu diffusion into the HfO2 layer. After switching to HRS again, Cu/Hf increased by 15 ± 5%, indicating that the Cu ion moved back to the top electrode side, though oxygen showed no bias voltage dependence. Consequently, the Cu ion has a key role in the switching. We directly observed the Cu migration behavior related to the resistive change at the Cu/HfO2 interface under bias operation.

Original languageEnglish
Article number06FG01
JournalJapanese journal of applied physics
Volume54
Issue number6
DOIs
Publication statusPublished - 2015 Jun 1
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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