Passivation of oxygen vacancy states in HfO2 by nitrogen

Xiong, K.; Robertson, J.; Clark, S.J.

doi:10.1063/1.2173688

Passivation of oxygen vacancy states in HfO2 by nitrogen

Xiong, K.; Robertson, J.; Clark, S.J.

Authors

K. Xiong

J. Robertson

Professor Stewart Clark s.j.clark@durham.ac.uk
Professor

Abstract

Nitrogen is known to reduce leakage currents and charge trapping in high-dielectric-constant gate oxides such as HfO2. We show that this occurs because nitrogen, substituting for oxygen atoms next to oxygen vacancy sites, repels the occupied gap states due to the neutral and positively charged oxygen vacancies out of the band gap into its conduction band. The state of the negatively charge vacancy is also repelled upwards but remains as a shallow gap state. This occurs because the vacancy becomes effectively positively charged; the adjacent Hf ions relax outwards from the vacancy and shift its states upwards. We show this using ab initio calculation methods which do not require an empirical correction to the band gap.

Citation

Xiong, K., Robertson, J., & Clark, S. (2006). Passivation of oxygen vacancy states in HfO2 by nitrogen. Journal of Applied Physics, 99(4), Article 044105. https://doi.org/10.1063/1.2173688

Journal Article Type	Article
Acceptance Date	Jan 3, 2006
Publication Date	Feb 15, 2006
Deposit Date	Jan 31, 2012
Publicly Available Date	Aug 18, 2015
Journal	Journal of Applied Physics
Print ISSN	0021-8979
Electronic ISSN	1089-7550
Publisher	American Institute of Physics
Peer Reviewed	Peer Reviewed
Volume	99
Issue	4
Article Number	044105
DOI	https://doi.org/10.1063/1.2173688

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© 2006 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics 99, 044105 (2006) and may be found at http://dx.doi.org/10.1063/1.2173688