Influence of Si content on the phase formation of W1-xSi x (0.30 ≤ x ≤ 0.74) gate electrodes and their work function

C. M. Lin, Jen-Sue Chen

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Tungsten silicide (W1-xSix, continuous increase in Si content ranging from 30 to 74 atom %) films are deposited on SiO2Si substrates by cosputtering from W and Si targets. After deposition, the samples are subject to a thermal annealing at 900°C to form crystalline silicide phases. With their almost stoichiometric compositions, 900°C annealed W 0.64Si0.36 and W0.31Si0.69 exhibit W5Si3 and WSi2 phases, respectively, while W0.44Si0.56 displays mixed phases of W5Si 3 and WSi2. With excess W, W0.70Si 0.30 film exhibits W5Si3 phase with a trace of body-centered cubic W. W0.26Si0.74 contains excess Si but shows a WSi2 phase of similar crystallinity to that of W 0.31Si0.69. Work functions of 900°C annealed W 0.70Si0.30, W0.64Si0.36, W 0.44Si0.56, W0.31Si0.69, and W 0.26Si0.74 are extracted from the plot of flatband voltage vs SiO2 thickness of the related metal-oxide-semiconductor capacitors, and the values are 4.34, 4.31, 4.61, 4.76, and 4.72 eV, respectively. It is deduced that the work function of W1-xSi x is mainly related with the phases, and their connection is discussed.

Original languageEnglish
JournalElectrochemical and Solid-State Letters
Volume11
Issue number11
DOIs
Publication statusPublished - 2008 Sep 22

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Materials Science(all)
  • Physical and Theoretical Chemistry
  • Electrochemistry
  • Electrical and Electronic Engineering

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