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Oxygen Vacancies in Amorphous HfO2 and SiO2

Published online by Cambridge University Press:  01 February 2011

Chioko Kaneta
Affiliation:
kaneta.chioko@jp.fujitsu.com, Fujitsu Laboratories Ltd., Nanotechnology Research Center, 10-1 Morinosato-Wakamiya, Atsugi, 243-0197, Japan
Takahiro Yamasaki
Affiliation:
t.yamasaki@jp.fujitsu.com, Fujitsu Laboratories Ltd., 10-1 Morinosato-Wakamiya, Atsugi, 243-0197, Japan
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Abstract

Formation energies and electronic properties of oxygen vacancies in amorphous HfO2 gate dielectrics are investigated by employing the first-principles method based on the density functional theory. We have found that the formation energy of neutral oxygen vacancy in amorphous HfO2 distributes from 4.7 to 6.1 eV, most of which is lower than the value for cubic HfO2, 6.0 eV. We also investigated the stabilities of the Vo pairs in various charged state and compared with those in amorphous SiO2. We found that Vo++ is stabilized in the vicinity of Vo in SiO2. In HfO2, however, this does not happen. This suggests the difference of defect propagation mechanism in HfO2 and SiO2.

Type
Research Article
Copyright
Copyright © Materials Research Society 2008

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References

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