Guiding principle of energy level controllability of silicon dangling bonds in HfSiON

Naoto Umezawa, Kenji Shiraishi, Seiichi Miyazaki, Akira Uedono, Yasushi Akasaka, Seiji Inumiya, Ryu Hasunuma, Kikuo Yamabe, Hiroyoshi Momida, Takahisa Ohno, Kenji Ohmori, Toyohiro Chikyow, Yasuo Nara, Keisaku Yamada

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Silicon dangling bonds (Si-DBs) in HfSiOx- have been studied using first-principles calculations. Interestingly, our computational result revealed that the Si-DB-related gap state in HfSiOx locates in a much lower energy region than that in SiOx. This is because Hf atoms enhance the ionic character of the HfSiOx film, which in turn induces a positive charge at the Si site. We consider that the low-lying Si-DB level, which is now very near the N 2p state, contributes to the formation of strong Si-N bonds in HfSiON. The lower shift of the Si-DB level upon cation metal inclusion can be useful information not only for improving the electric properties of high-k gate stacks but also for developing prominent silicon-oxide-nitride-oxide-silicon (SONOS) nonvolatile memories where controllability of the charge trap level is a crucial issue.

Original languageEnglish
Pages (from-to)1891-1894
Number of pages4
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Issue number4 B
Publication statusPublished - 2007 Apr 24
Externally publishedYes


  • HfSiON
  • High-k dielectrics
  • Silicon dangling bond

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)


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