Summary: Electronic structure of transition metal high-k dielectrics:
interfacial band offset energies for microelectronic devices
, Gilbert B. Rayner Jr., Yu Zhang, Charles C. Fulton,
Robert J. Nemanich, Guenther Appel, Harald Ade, Jerry L. Whitten
Department of Physics, North Carolina State University, Campus Box 8202, Raleigh, NC 27695, USA
Transition metal silicates, (ZrO2)x(SiO2)1└x, have dielectric constants k > 10 that make them attractive for advanced Si
devices. Band offset energies relative to Si are an important factor in determining tunneling leakage current, and internal
photoemission. Studies by X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and X-ray absorption
spectroscopy (XAS) are combined with ab initio calculations to identify the compositional variation of the band-gap, and
valence and conduction band offset energies of Zr silicate alloys with respect to Si. The minimum conduction band offset, due to
states, is shown to be independent of alloy composition, while valence band offsets decrease monotonically with
increasing ZrO2 content. The implications of these results for direct tunneling are discussed.
# 2003 Elsevier Science B.V. All rights reserved.
PACS: 71.55.Jv; 75.55.■f; 73.20.At
Keywords: Ab initio quantum chemical calculations; Plasma processing; Auger electron spectroscopy; X-ray photoelectron spectroscopy;
X-ray absorption spectroscopy; Zirconium silicate alloys; Semiconductorşinsulator interfaces