Work function tailoring of carbon-added tungsten gate electrodes

C. M. Lin, S. Y. Shen, Jen-Sue Chen

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

In this work, carbon-added tungsten (W1-x Cx, x≤0.19) and thin carbon layer-inserted tungsten (Wtop /C/ W bottom, the thickness of Wbottom is set to be 2 nm and 10 nm) gate stacks are deposited on Si O2 /Si to fabricate metal-oxide-semiconductor capacitors. Grazing incident angle X-ray diffraction reveals that the W1-x Cx films become amorphous when the concentration of added C is lower than 16 atom %. However, when the C concentration is as high as 19 atom %, a trace of γ phase of tungsten carbide phase appears in the W0.81 C0.19 film. No interdiffusion between C-added W and Si O2 is observed by Auger electron spectroscopy depth profiling. The resistivity of W, W0.88 C0.12, W0.84 C0.16, and W0.81 C 0.19 are 132, 151, 163, and 337 μcm, respectively. The work function of W0.81 C0.19, W0.84 C 0.16, W0.88 C0.12, W, W/C/W (10 nm), and W/C/W (2 nm) on Si O2 are 4.82, 4.75, 4.73, 4.66, 4.52, and 4.32 eV, respectively. The C-related dipole shows apparent influence on the work function. The leakage current densities of C-added W films are smaller than 2× 10-5 A/ cm2 in the range from 0 to 5 × 107 V/cm. No significant influence of these gate electrodes on the fixed oxide charge and the leakage behavior of Si O2 are observed.

Original languageEnglish
JournalJournal of the Electrochemical Society
Volume158
Issue number2
DOIs
Publication statusPublished - 2011 Jan 5

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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