Band offsets of a ruthenium gate on ultrathin high-{kappa} oxide films on silicon

Journal Article · Sun Feb 15 00:00:00 EST 2009 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.79.075106· OSTI ID:21192539

Rangan, Sylvie; Bersch, Eric; Bartynski, Robert Allen; Garfunkel, Eric; Vescovo, Elio ^[1]

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1. Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854 (United States)

Valence-band and conduction-band edges of ultrathin oxides (SiO{sub 2}, HfO{sub 2}, Hf{sub 0.7}Si{sub 0.3}O{sub 2}, and Al{sub 2}O{sub 3} 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 SiO{sub 2} in the case of the high-{kappa} 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.

• OSTI ID: 21192539
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 79, Issue 7; Other Information: DOI: 10.1103/PhysRevB.79.075106; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM OXIDES
DEPOSITION
DIELECTRIC MATERIALS
DIPOLES
ENERGY GAP
HAFNIUM OXIDES
INTERFACES
PHOTOEMISSION
RUTHENIUM
RUTHENIUM OXIDES
SILICON
SILICON OXIDES
SUBSTRATES
SYNCHROTRON RADIATION
THIN FILMS
ULTRAVIOLET RADIATION
VALENCE
WORK FUNCTIONS
X RADIATION
X-RAY PHOTOELECTRON SPECTROSCOPY