On the thermal stability of atomic layer deposited TiN as gate electrode in MOS devices

The work function of ALD TiN was found to be above 5 eV after RTP annealing below 800/spl deg/C in a nitrogen atmosphere, while higher annealing temperatures cause a drop in work function by about 0.3-0.5 eV. The effect was found for TiN metal gates on both SiO/sub 2/ and Al/sub 2/O/sub 3/ gate diel...

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Bibliographic Details
Published in:IEEE electron device letters 2003-09, Vol.24 (9), p.550-552
Main Authors: Westlinder, J., Schram, T., Pantisano, L., Cartier, E., Kerber, A., Lujan, G.S., Olsson, J., Groeseneken, G.
Format: Article
Language:English
Subjects:
Annealing
Atmosphere
Atmospheres
Atomic layer deposition
Dielectrics
Electrodes
Gates
MOS devices
Nitrogen
Silicon dioxide
Temperature
Thermal stability
Tin
Work functions
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Summary:The work function of ALD TiN was found to be above 5 eV after RTP annealing below 800/spl deg/C in a nitrogen atmosphere, while higher annealing temperatures cause a drop in work function by about 0.3-0.5 eV. The effect was found for TiN metal gates on both SiO/sub 2/ and Al/sub 2/O/sub 3/ gate dielectrics in MOS-capacitors and was seen in C-V as well as in I-V measurements. On the contrary, annealing of SiO/sub 2/ capacitors in oxygen-enriched N/sub 2/ atmosphere increased the work function. A variation in EOT of less than 2 A was demonstrated for the various annealing temperatures, concluding that the ALD TiN is stable in contact with the different dielectric materials. However, the decrease in work function that is found in this investigation may implicate that ALD TiN is less suitable as a metal gate for pMOSFETs.
ISSN:0741-3106
1558-0563
1558-0563
DOI:10.1109/LED.2003.816579