Open AccessInterfacial oxygen and nitrogen induced dipole formation and vacancy passivation for increased effective work functions in TiN/HfO2 gate stacks
Author(s) -
Christopher L. Hinkle,
Rohit Galatage,
R. A. Chapman,
Eric M. Vogel,
Husam N. Alshareef,
C. M. Freeman,
E. Wimmer,
H. Niimi,
A. Li-Fatou,
J. B. Shaw,
James J. Chambers
Publication year - 2010
Publication title -
applied physics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 442
eISSN - 1077-3118
pISSN - 0003-6951
DOI - 10.1063/1.3353993
Subject(s) - tin , passivation , work function , oxygen , materials science , dipole , metal gate , nitrogen , dielectric , annealing (glass) , forming gas , metal , optoelectronics , chemistry , nanotechnology , metallurgy , gate oxide , electrical engineering , layer (electronics) , organic chemistry , engineering , transistor , voltage
Effective work function (EWF) changes of TiN/HfO2annealed at low temperatures in different ambient environments are correlated with the atomic concentration of oxygen in the TiN near the metal/dielectric interface. EWF increases of 550 meV are achieved with anneals that incorporate oxygen throughout the TiN with [O]=2.8×1021 cm−3 near the TiN/HfO2interface. However, further increasing the oxygen concentration via more aggressive anneals results in a relative decrease of the EWF and increase in electrical thickness. First-principles calculations indicate the exchange of O and N atoms near the TiN/HfO2interface cause the formation of dipoles that increase the EWF
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