(Invited) Band-Edge Effective Work Functions by Controlling HfO 2 /TiN Interfacial Composition for Gate-Last CMOS

Effective work function (EWF) changes of TiN/HfO 2 annealed at low temperatures in different ambient environments are correlated to the atomic concentration of oxygen, nitrogen, and aluminum at the metal/dielectric interface. Low EWFs (4.0 eV) are obtained by allowing aluminum to migrate to the TiN/...

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Bibliographic Details
Published in:ECS transactions 2011-04, Vol.35 (2), p.285-295
Main Authors: Hinkle, Christopher, Galatage, Rohit, Chapman, Richard, Vogel, Eric, Alshareef, H. N., Freeman, Clive, Wimmer, Erich, Niimi, Hiro, Li-Fatou, Andrei, Chambers, James, Shaw, Judy
Format: Article
Language:English
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Summary:Effective work function (EWF) changes of TiN/HfO 2 annealed at low temperatures in different ambient environments are correlated to the atomic concentration of oxygen, nitrogen, and aluminum at the metal/dielectric interface. Low EWFs (4.0 eV) are obtained by allowing aluminum to migrate to the TiN/HfO 2 interface during a forming gas anneal. High EWFs (5.1 eV) are achieved with anneals that incorporate oxygen throughout the TiN with [O] = 2.8x10 21 cm -3 near the TiN/HfO 2 interface. First-principles calculations indicate the exchange of O and N atoms near the TiN/HfO 2 interface cause the formation of dipoles that increase the EWF.
ISSN:1938-5862
1938-6737
DOI:10.1149/1.3568871