Effect of nitrogen incorporation and oxygen vacancy on electronic structure and the absence of a gap state in HfSiO films

Moon Hyung Jang, Kwang Sik Jeong, Kwun Bum Chung, Jin Woo Lee, Myeung Hee Lee, Mann Ho Cho

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5 Scopus citations

Abstract

The effect of nitrogen (N) incorporation into HfSiO on the electronic structure and band alignment of HfSiO films was investigated. N depth profile data obtained by medium energy ion scattering (MEIS) showed that the concentration of N or the bonding or electronic state of N in the film was stable when the film was annealed at 950°C, while the oxygen (O) in HfSiON films was present in dissociated form, as evidenced by the unoccupied electronic state of O. The valence band offsets of the HfSiO films were strongly affected by N incorporation due to the presence of N in a 2p state. Moreover, a reduction in the conduction band offset of a HfSiO film was confirmed after the film was annealed in an atmosphere of N 2. The unoccupied state of the O vacancy is responsible for the change in the conduction band offset. The results of ab-initio calculations for the density of states (DOS) of HfSiO and HfSiON supercells were in agreement with the experimental results. The incorporation on N into HfSiO prevents the formation of a gap-state inside the band gap despite the fact that an O vacancy is generated in the film.

Original languageEnglish
Pages (from-to)L64-L68
JournalSurface Science
Volume606
Issue number15-16
DOIs
StatePublished - Aug 2012

Keywords

  • Ab-initio calculations
  • Absence of gap state
  • HfSiO
  • Medium energy ion scattering
  • Near-edge x-ray absorption fine structure
  • Reflection electron energy loss spectroscopy

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