The importance of contacts in Cu2GeTe3phase change memory devices

Satoshi Shindo, Yi Shuang, Shogo Hatayama, Yuta Saito, Paul Fons, Alexander V. Kolobov, Keisuke Kobayashi

Research output: Contribution to journalArticlepeer-review

Abstract

Cu2GeTe3 (CGT) is a promising phase change material for phase change random access memory (PCRAM) applications because of its high thermal stability in the amorphous phase and its capability to undergo rapid phase change. In this paper, the electrical conduction mechanism of a CGT memory device fabricated using W electrodes (W/CGT) was investigated using current-voltage (I-V) measurements and angle resolved hard x-ray photoelectron spectroscopy (AR-HAXPES). The I-V characteristics of the W/CGT memory device were found to display non-linear behavior in the RESET (amorphous) state, while linear behavior was observed in the SET (crystalline) state, indicating that the W/CGT memory device exhibited Schottky conduction in the RESET state, but Ohmic conduction in the SET state. The effective Schottky barrier height was found to increase linearly as the ideality factor decreased to unity with the ideal W/CGT Schottky barrier height in the RESET state estimated to be 0.33 eV, a value in good agreement with the directly measured Schottky barrier height of 0.35 eV between W and amorphous CGT by AR-HAXPES measurements. These results suggest that the interface between the metal electrode and the phase change material plays an important role in PCRAM devices, and its comprehensive understanding is necessary for future application development.

Original languageEnglish
Article number165105
JournalJournal of Applied Physics
Volume128
Issue number16
DOIs
Publication statusPublished - 2020 Oct 28
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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