Microstructural evolution and electrical resistivity of nanocrystalline W thin films grown by sputtering

Yong Jin Kim, Sung Gyu Kang, Yeonju Oh, Gyu Won Kim, In Ho Cha, Heung Nam Han, Young Keun Kim

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Tungsten (W) thin films and nanostructures, particularly those having a beta (β)-phase, have attracted a large amount of attention lately because an ultrathin β-phase W film attached to a ferromagnetic layer can reverse the direction of magnetization upon current injection. However, in-depth microstructural studies including the phase transformation in W films as a function of thickness and post-deposition heat treatment temperature are rare. Here, we report the microstructural evolution and the change in the electrical resistivity of W films with thicknesses of 5–40 nm. Microstructural analyses indicate that the β-W is nanocrystalline with a small grain size of about 5 nm, while the alpha (α)-W has a grain size larger than 130 nm with random crystal orientation. We present a state diagram showing the phase of the W film as functions of film thickness and annealing temperature.

Original languageEnglish
Pages (from-to)473-478
Number of pages6
JournalMaterials Characterization
Volume145
DOIs
Publication statusPublished - 2018 Nov 1

Keywords

  • Electrical resistivity
  • Microstructure
  • Phase
  • TEM ASTAR
  • Thin film
  • Tungsten (W)

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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