Atomic-layer-resolved bandgap structure of an ultrathin oxynitride-silicon film epitaxially grown on 6H-SiC (0001)

T. Shirasawa, K. Hayashi, H. Yoshida, S. Mizuno, S. Tanaka, T. Muro, Y. Tamenori, Y. Harada, T. Tokushima, Y. Horikawa, E. Kobayashi, T. Kinoshita, S. Shin, T. Takahashi, Y. Ando, K. Akagi, S. Tsuneyuki, H. Tochihara

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Abstract

Electronic structures of a silicon-oxynitride (SiON) layer (∼0.6 nm in thickness) epitaxially grown on 6H-SiC (0001) were investigated on atomic-layer scale using soft x-ray absorption spectroscopy and x-ray emission spectroscopy (XAS and XES) and first-principles calculations. The SiON layer has a hetero-double-layered structure: an interfacial silicon nitride layer and a silicon oxide overlayer. The element-specific XAS and XES measurements revealed layer-resolved energy-band profiles. Measured gap sizes are 6.3±0.6 eV at the nitride layer and 8.3±0.8 eV at the oxide layer. The nitride and oxide layers have almost the same energy of conduction-band minimum (CBM) being ∼3 eV higher than CBM of the SiC substrate. The energy-band profiles of the SiON layer are qualitatively reproduced by the calculations. The calculations show that broadening of bandgap of the substrate occurs only at an interfacial SiC bilayer.

Original languageEnglish
Article number241301
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume79
Issue number24
DOIs
Publication statusPublished - Jun 1 2009

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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    Shirasawa, T., Hayashi, K., Yoshida, H., Mizuno, S., Tanaka, S., Muro, T., Tamenori, Y., Harada, Y., Tokushima, T., Horikawa, Y., Kobayashi, E., Kinoshita, T., Shin, S., Takahashi, T., Ando, Y., Akagi, K., Tsuneyuki, S., & Tochihara, H. (2009). Atomic-layer-resolved bandgap structure of an ultrathin oxynitride-silicon film epitaxially grown on 6H-SiC (0001). Physical Review B - Condensed Matter and Materials Physics, 79(24), [241301]. https://doi.org/10.1103/PhysRevB.79.241301