Fabrication and characterization of Cu2O/Cu-WO3 bilayers for lateral programmable metallization cells

Mehmet B. Balaban, Ninad Chamele, Smitha S. Swain, Yago Gonzalez Velo, Michael N. Kozicki

Research output: Contribution to journalArticle

Abstract

Lateral Programmable Metallization Cell (PMC) structures rely on metal electrodeposition in a long channel consisting of a solid electrolyte layer between an anode and a cathode. Integration of these devices with CMOS circuitry demands using materials such as copper and tungsten for the electrodes, and an oxide of tungsten (WO3) doped with Cu for the electrolyte. However, low diffusivity of Cu in WO3 and its high resistivity results in a slow electrodeposition process. Our solution to this problem involves the use of a Cu2O/Cu-WO3 bilayer, formed by oxidation of a thin Cu film on a WO3 layer and a simultaneous diffusion of Cu into the WO3 at moderate temperatures. This creates a Cu-WO3 solid electrolyte with a semiconducting Cu2O coating that brings electrons to where the ions are most abundant and thereby greatly increases the electrodeposition rate. In this paper, an investigation of thin film Cu oxidation is presented along with the diffusion kinetics of Cu in WO3. The Cu was oxidized in air to form Cu2O with an activation energy of 0.70 eV. The diffusion analysis showed activation energy of Cu diffusion in WO3 was 0.74 eV, which we believe is the first time this value has been reported.

Original languageEnglish (US)
Article number146899
JournalApplied Surface Science
Volume527
DOIs
StatePublished - Oct 15 2020

Keywords

  • Copper (Cu)
  • Cuprous oxide (CuO)
  • Diffusion
  • Low temperature oxidation
  • Tungsten oxide (WO)

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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