Electrical and Material Evaluation of the MOCVD TiN as Metal Gate Electrode for
Advanced CMOS Technology
Raghunath Singanamalla
1,2
, Judit Lisoni
1
, Isabelle Ferain
1,2
, Olivier Richard
1
, Laure
Carbonell
1
, Tom Schram
1
, HongYu Yu
1
, Stefan Kubicek
1
, Stefan de Gendt
1,3
, Malgorzata
Jurczak
1
, and Kristin de Meyer
1,2
1
IMEC, Leuven, 3001, Belgium
2
ESAT, University of Leuven, Leuven, 3001, Belgium
3
Chemistry, University of Leuven, Leuven, 3001, Belgium
ABSTRACT
The electrical and material characterization of Ti(C)N deposited by metal organic
chemical vapor deposition (MOCVD) technique, as metal gate electrode for advanced
CMOS technology is investigated. The effects of the plasma treatment, post anneal
treatment and the thickness variation of the Ti(C)N film on the flat band voltage (V
FB
)
and effective work function (WF) of the Poly-Si/Ti(C)N/SiO
2
Poly-Si/Ti(C)N/SiO
2
gate
stack s are reported. We found that both the in-situ plasma treatment and post anneal
treatment help in reducing the carbon content (organic) in the film making it more
metallic compared to the as-deposited films. However, the post anneal treatment was
found to be a better option for getting rid of hydrocarbons as compared to plasma
treatment from the gate dielectric integrity point of view. The thickness variation of post
annealed Ti(C)N film ranged from 2.5 nm to 10 nm lead to WF shift of upto ~350 mV for
both Poly-Si/Ti(C)N/SiO
2
and Poly-Si/Ti(C)N/HfO
2
gate stacks.
INTRODUCTION
To meet the ITRS specification for the 45 nm node and beyond the poly-Si gates will
have to be replaced by metal gate electrodes [1]. Metal gate electrodes not only eliminate
the gate depletion and dopant penetration problems in CMOS transistors, but also reduce
the gate sheet resistance. The possibility to modulate their WF through the nitrogen
content has already been reported [2]. In this work the Ti(C)N film is deposited by Metal
Organic Chemical Vapor Deposition (MOCVD) technique. The Ti(C)N deposited is
highly porous and has high sheet resistance because of high amounts of hydrocarbon
compounds (precursor residues). These organic compounds can be reduced either by in-
situ plasma or ex-situ anneal treatments. In this paper, we investigate the effect of these
treatments on the V
FB
and the gate dielectric integrity. We also report the micro-structural
characterization of the TiN films before and after the plasma and post anneal treatments.
WF modulation of the post annealed (@ 700
o
C, 5 min. in N
2
) Poly-Si/Ti(C)N/SiO
2
and
Poly-Si/Ti(C)N/HfO
2
gate stacks as a function of thickness variation of Ti(C)N are also
reported.
Mater. Res. Soc. Symp. Proc. Vol. 917 © 2006 Materials Research Society 0917-E12-02