Band offsets of a ruthenium gate on ultrathin high- κ oxide films on silicon

Sylvie Rangan, Eric Bersch, Robert Allen Bartynski, Eric Garfunkel, Elio Vescovo

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Valence-band and conduction-band edges of ultrathin oxides (SiO2, HfO2, Hf0.7 Si0.3 O2, and Al2 O3 grown on silicon) and their shifts upon sequential metallization with ruthenium have been measured using synchrotron-radiation- excited x-ray, ultraviolet, and inverse photoemissions. From these techniques, the offsets between the valence-band and conduction-band edges of the oxides, and the ruthenium metal gate Fermi edge have been directly measured. In addition the core levels of the oxides and the ruthenium have been characterized. Upon deposition, Ru remains metallic and no chemical alteration of the underlying oxide gates, or interfacial SiO2 in the case of the high- κ thin films, can be detected. However a clear shift of the band edges is measured for all samples due to the creation of an interface dipole at the ruthenium-oxide interface. Using the energy gap, the electron affinity of the oxides, and the ruthenium work function that have been directly measured on these samples, the experimental band offsets are compared to those predicted by the induced gap states model.

Original languageEnglish
Article number075106
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume79
Issue number7
DOIs
Publication statusPublished - Feb 2 2009

Fingerprint

Ruthenium
Silicon
Oxides
ruthenium
Oxide films
oxide films
oxides
silicon
Valence bands
Conduction bands
conduction bands
valence
Electron affinity
Core levels
shift
Photoemission
Metallizing
electron affinity
Synchrotron radiation
synchrotron radiation

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Band offsets of a ruthenium gate on ultrathin high- κ oxide films on silicon. / Rangan, Sylvie; Bersch, Eric; Bartynski, Robert Allen; Garfunkel, Eric; Vescovo, Elio.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 79, No. 7, 075106, 02.02.2009.

Research output: Contribution to journalArticle

Rangan, Sylvie ; Bersch, Eric ; Bartynski, Robert Allen ; Garfunkel, Eric ; Vescovo, Elio. / Band offsets of a ruthenium gate on ultrathin high- κ oxide films on silicon. In: Physical Review B - Condensed Matter and Materials Physics. 2009 ; Vol. 79, No. 7.
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