Study of metal gate work function modulation using plasma and SiH4 treated TiN thin films

2003 ◽  
Vol 786 ◽  
Author(s):  
F. Fillot ◽  
S. Maîtrejean ◽  
T. Farjot ◽  
B. Guillaumot ◽  
B. Chenevier ◽  
...  
Keyword(s):  
Thin Films ◽  
Work Function ◽  
Film Growth ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Flat Band ◽  
Metal Gate ◽  
Polysilicon Gate ◽  
Tin Thin Films ◽  
Tin Metal

ABSTRACTAs gate oxide thickness decreases, the capacitance associated with the depleted layer in polysilicon gate becomes significant, making it necessary to consider alternative gate electrodes. Titanium nitride (TiN) films elaborated with TiCl4 precursor is widely studied as metal gate in semi-conductor technology. In this work, a study of TiN metal gate deposited by MOCVD using TDMAT (Tetrakisdimethylamino titanium) precursor is proposed. N2, H2 plasma application and SiH4 treatment after TiN thin film growth modify composition and microstructure. Consequently, they alter the physical properties of films. Such treatments may be a way to modulate work function and thus to control threshold voltage.Metallic layers were deposited in a chamber using a commercial 8 inch wafer deposition tool. In this study, structural and compositional properties of TiN were correlated with work function measurements. Firstly, the composition evolution (carbon content) was studied by AES and SIMS as a function of plasma and SiH4 treatments; XRD gave details on the microstructure. Secondly, MOS structures were processed on uniformly p-type doped wafers. C-V curves of capacitors were used to estimate the flat band voltage (VFB) and gave access to the work function, the effect of oxide fixed charges and the density of interface states. It is shown that as-deposited amorphous films exhibit a work function of 4.4 eV. Exposure to SiH4 is shown to increase this work function of about 150 meV. Thin films properties are not impacted by anneal treatments. Work function stability was tested at 425 °C, 900 °C and 1050 °C. Thermodynamic compatibility with gate oxide was verified thanks to experimental results and calculations.

Nickel Silicide Work Function Tuning Study In Metal-Gate CMOS Applications

2004 ◽  
Vol 829 ◽  
Author(s):  
Jun Yuan ◽  
Grant Z. Pan ◽  
Yu-Lin Chao ◽  
Jason C.S. Woo
Keyword(s):  
Work Function ◽  
High Performance ◽  
Gate Oxide ◽  
Nickel Silicide ◽  
Oxide Semiconductor ◽  
Flat Band ◽  
Oxide Interface ◽  
Metal Gate ◽  
Activation Temperature ◽  
Pile Up

ABSTRACTMid-gap work function (∼4.7eV) for mono-nickel-silicide (NiSi) was obtained by extrapolating flat band voltages of metal-oxide-semiconductor (MOS) capacitors with different gate oxide thickness. Both silicidation temperature and time can affect the nickel silicide work function as a result of different Ni:Si ratio close to the gate oxide interface. Arsenic implantation into the polysilicon before silicidation can shift the NiSi work function towards the silicon conduction band, which makes it suitable for high performance NMOS applications. The physical mechanism responsible for this work function shift is arsenic pile-up at the oxide interface during the nickel silicidation process. Therefore, dual work function metal gate can be obtained by using a single gate full silicidation process. Silicidation temperature and time also affect the work function shift from arsenic dopant, and the incomplete gate silicidation can have the maximum work function modification effect. Arsenic activation temperature before silicidation was found to have a significant effect on the work function shift. Un-annealed samples exhibit a minimum shift in work function due to the low dopant pile-up concentration at the oxide interface.

Study of work function of CVD WSix thin film on high K dielectric.

2003 ◽  
Vol 786 ◽  
Author(s):  
S. Maîtrejean ◽  
S. Allégret ◽  
F. Fillot ◽  
T. Farjot ◽  
B. Guillaumot ◽  
...  
Keyword(s):  
Thin Films ◽  
Work Function ◽  
Dielectric Film ◽  
Oxide Thickness ◽  
Metal Gate ◽  
Mos Capacitors ◽  
Depletion Effect ◽  
High K ◽  
High K Materials ◽  
Nominal Stoichiometry

ABSTRACTTo meet requirements of CMOS circuits at sub 45nm scale, gate oxide thickness shall decrease. Thus high K materials are needed as dielectric gate. In this setting, due to gate depletion effect, metallic material should be used as an alternative to poly silicon gate. Moreover, specifications on threshold voltage require modulation of gate material work function with respect to nMOS or pMOS transistor. WSix work function is known to be sensitive to material stoichiometry. In this work, WSix thin films with x between 2.2 and 2.5 are evaluated as metal gate on HfO2 and SiO2 dielectric. Film chemical characteristics are correlated with work function measurements.Thin films are deposited using WF6 and dichlorosilane on a 200mm wafer industrial chamber. Thermal treatments are applied to sample in order to recrystallise the film and confirm it stability. MOS Capacitors are processed. Electrical characterizations (capacitance vs voltage) are used to extract work function with respect to film composition.Films are chemically and morphologically stable up to 800°C. A W/Si ratio gradient is observed between surface and dielectric/film interface. Whatever the nominal stoichiometry, Si/W ratio is constant at this interface. This result is correlated with identical work function measurement for different nominal stoichiometry. Moreover no differences are observed between Vfb vs equivalent oxide thickness curves for HfO2 and SiO2 dielectric. High EOT variations have been identified for SiO2 capacitors in contrast with SiO2/HfO2 capacitors. These results characterize WSix as a suitable metal gate for nMOS transistors.

scholarly journals A Study on Improvement and Degradation of Si/SiO2Interface Property for Gate Oxide with TiN Metal Gate

2008 ◽  
Vol 9 (1) ◽  
pp. 6-11 ◽  
Author(s):  
Byung-Hyun Lee ◽  
Yong-Il Kim ◽  
Bong-Soo Kim ◽  
Dong-Soo Woo ◽  
Yong-Jik Park ◽  
...  
Keyword(s):  
Gate Oxide ◽  
Metal Gate ◽  
Tin Metal

Deep insights into electrical parameters due to metal gate WFV for different gate oxide thickness in Si step FinFET

2019 ◽  
Vol 14 (4) ◽  
pp. 384-388
Author(s):  
Rajesh Saha ◽  
Brinda Bhowmick ◽  
Srimanta Baishya
Keyword(s):  
Gate Oxide ◽  
Oxide Thickness ◽  
Electrical Parameters ◽  
Metal Gate ◽  
Gate Oxide Thickness

Thermally stable high effective work function TaCN thin films for metal gate electrode applications

2009 ◽  
Vol 105 (5) ◽  
pp. 053516 ◽  
Author(s):  
C. Adelmann ◽  
J. Meersschaut ◽  
L.-Å. Ragnarsson ◽  
T. Conard ◽  
A. Franquet ◽  
...  
Keyword(s):  
Thin Films ◽  
Work Function ◽  
Thermally Stable ◽  
Gate Electrode ◽  
Metal Gate ◽  
Effective Work ◽  
Effective Work Function

Work-Function-Tuned TiN Metal Gate FDSOI Transistors for Subthreshold Operation

2011 ◽  
Vol 58 (2) ◽  
pp. 419-426 ◽  
Author(s):  
Steven A. Vitale ◽  
Jakub Kedzierski ◽  
Paul Healey ◽  
Peter W. Wyatt ◽  
Craig L. Keast
Keyword(s):  
Work Function ◽  
Metal Gate ◽  
Tin Metal ◽  
Subthreshold Operation

scholarly journals Microstructure, Stress and Texture in Sputter Deposited TiN Thin Films: Effect of Substrate Bias

2014 ◽  
Vol 996 ◽  
pp. 855-859 ◽  
Author(s):  
Jay Chakraborty ◽  
Tias Maity ◽  
Kishor Kumar ◽  
S. Mukherjee
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Profile Analysis ◽  
Lattice Parameter ◽  
Line Profile Analysis ◽  
Substrate Bias ◽  
X Ray Diffraction ◽  
Strain Anisotropy ◽  
X Ray ◽  
Tin Thin Films

Titanium nitride thin films deposited by reactive dc magnetron sputtering under various substrate bias voltages have been investigated by X-ray diffraction. TiN thin films exhibits lattice parameter anisotropy for all bias voltages. Preferential entrapment of argon atoms in TiN lattice has been identified as the major cause of lattice parameter anisotropy. Bombardment of argon ions during film growth has produced stacking faults on {111} planes of TiN crystal. Stacking fault probability increases with increasing substrate bias voltages. X-ray diffraction line profile analysis indicates strain anisotropy in TiN thin films. Diffraction stress analysis by d-sin2ψ method reveals pronounced curvature in the plot of inter-planar spacing (d) (or corresponding lattice parameter (a)) versus sin2ψ. Direction dependent elastic grain interaction has been considered as possible source of the observed anisotropic line broadening.

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