Role of the ionicity in defect formation in Hf-based dielectrics

N. Umezawa, K. Shiraishi, S. Miyazaki, A. Uedono, Y. Akasaka, S. Inumiya, A. Oshiyama, R. Hasunuma, K. Yamabe, H. Momida, T. Ohno, K. Ohmori, T. Chikyow, Y. Nara, K. Yamada

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

Ionicity has been raised as an important factor in discussing defect formation in Hf-based oxides. It has been elucidated from our first-principles calculations, that the stability of defects is dominated by Coulomb interactions between charged defects and surrounding ions. For instance, the formation energy of positively charged oxygen vacancies (Vo+2) is markedly decreased when they are coupled with substitutional N atoms at O sites, as the nominal charges of N3- are negatively greater than those of the oxygen ions O2-. Our computational results have further revealed that the ionic character of Hf causes generation of a low-lying Si dangling bond level in Si doped HfSiOx. These results suggest that one must take into account the ionicity of the Hf-based compounds, which possess totally different properties from the conventional gate insulator SiO2 in terms of defect formation.

Original languageEnglish
Title of host publicationECS Transactions - 5th International Symposium on High Dielectric Constant Materials and Gate Stacks
Pages199-211
Number of pages13
Edition4
DOIs
Publication statusPublished - 2007 Dec 1
Event5th International Symposium on High Dielectric Constant Materials and Gate Stacks - 212th ECS Meeting - Washington, DC, United States
Duration: 2007 Oct 82007 Oct 10

Publication series

NameECS Transactions
Number4
Volume11
ISSN (Print)1938-5862
ISSN (Electronic)1938-6737

Other

Other5th International Symposium on High Dielectric Constant Materials and Gate Stacks - 212th ECS Meeting
Country/TerritoryUnited States
CityWashington, DC
Period07/10/807/10/10

ASJC Scopus subject areas

  • Engineering(all)

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