Band alignment of a HfO2-VO2-HfO2 confined well structure on silicon

Contributors:   Chiyu Zhu, Sean L. Caudle, Jianling Yang, David J. Smith, and Robert J. Nemanich

ABSTRACT

Vanadium dioxide (VO2) is a narrow band gap material that undergoes a metal-insulator phase transition at ∼343 K with evidence of an electric-field induced transition at T < 343 K. In this study, a sandwich-type dielectric structure is prepared consisting of two ∼1.5 nm hafnium oxide (HfO2) layers with a ∼1.0 nm VO2 interlayer grown on an oxidized n-type silicon substrate. The electronic properties of the sample were characterized by in-situ x-ray and ultraviolet photoelectron spectroscopy after each layer was deposited. The band alignment was analyzed after each growth step. The SiO2/HfO2 interface valence band offset is found to be 0.7 eV, and the HfO2/VO2 interface valence band offset is determined to be 3.4 eV.

Publisher: Journal of Vacuum Science and Technology B,   Volume: 32,   Published: 2013-11 ||   PDF (1.21 MB) ||   Read more...