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Thermally-Stable High Effective Work Function TaCN and Ta2N Films for pMOS Metal Gate Applications

Published online by Cambridge University Press:  01 February 2011

Christoph Adelmann
Affiliation:
[email protected], IMEC vzw., AMPS/TFGS, Kapeldreef 75, Leuven, B-3001, Belgium, ++32-16-287613
P. Lehnen
Affiliation:
[email protected], Aixtron AG, Aachen, 52072, Germany
L.-Å. Ragnarsson
Affiliation:
[email protected], IMEC vzw., Kapeldreef 75, Leuven, B-3001, Belgium
T. Conard
Affiliation:
[email protected], IMEC vzw., Kapeldreef 75, Leuven, B-3001, Belgium
A. Franquet
Affiliation:
[email protected], IMEC vzw., Kapeldreef 75, Leuven, B-3001, Belgium
V. S. Chang
Affiliation:
[email protected], IMEC vzw., Kapeldreef 75, Leuven, B-3001, Belgium
E. Rohr
Affiliation:
[email protected], IMEC vzw., Kapeldreef 75, Leuven, B-3001, Belgium
J. Meersschaut
Affiliation:
[email protected], IMEC vzw., Kapeldreef 75, Leuven, B-3001, Belgium
O. Boissière
Affiliation:
[email protected], Aixtron AG, Aachen, 52072, Germany
C. Lohe
Affiliation:
[email protected], Aixtron AG, Aachen, 52072, Germany
T. Schram
Affiliation:
[email protected], IMEC vzw., Kapeldreef 75, Leuven, B-3001, Belgium
S. Van Elshocht
Affiliation:
[email protected], IMEC vzw., Kapeldreef 75, Leuven, B-3001, Belgium
S. De Gendt
Affiliation:
[email protected], IMEC vzw., Kapeldreef 75, Leuven, B-3001, Belgium
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Abstract

TaCN-based metal films were grown by metal-organic chemical-vapor deposition (MOCVD) and atomic vapor-deposition (AVD). Thermal decomposition at 500ºC leads to com-positions of approximately Ta0.50C0.4N0.1 (“TaCN”), whereas a reactive process using NH3 leads to the formation of Ta0.65C0.1N0.25 (“Ta2N”) films. All films are nearly amorphous as grown and recrystallize only weakly after spike annealing at 1050°C. The thermal stability of TaCN/HfSiO4 and Ta2N/HfSiO4 stacks during spike annealing at 1050°C was studied and Si and Hf outdiffusion into TaCN or Ta2N was observed. The effective work functions of TaCN and Ta2N on HfSiO4 were found to be as high as 4.9 eV after high thermal budget. It is demonstrated that the effective work function can be further increased to 5.1 eV after high thermal budget by the insertion of a thin Al2O3 capping layer between HfSiO4 and the metal films.

Type
Research Article
Copyright
Copyright © Materials Research Society 2008

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References

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