Title: Atomic layer deposition of hafnium silicate gate dielectric layers
Authors: Delabie, Annelies ×
Pourtois, Geoffrey
Caymax, Matty
De Gendt, Stefan
Ragnarsson, Lars-Ake
Heyns, Marc
Fedorenko, Yanina
Swerts, Johan
Maes, Jan Willem #
Issue Date: Jul-2007
Publisher: A v s amer inst physics
Series Title: Journal of vacuum science & technology a vol:25 issue:4 pages:1302-1308
Abstract: Downscaling equivalent oxide thickness (EOT) by decreasing the physical thickness or increasing the permittivity of the gate dielectric is required to reach the complementary metal-oxide semiconductor (CMOS) (sub) 45 nm node performance specifications. In this work, we study the atomic layer deposition (ALD) of hafnium silicate gate dielectrics from HfCl4, SiCl4, and H2O both experimentally and theoretically. Hafnium silicate is characterized by Rutherford backscattering, time-of-flight secondary ion mass spectroscopy, and x-ray photoelectron spectroscopy. The interaction of the precursors with the surface sites is investigated by first-principles calculations. The electrical properties are evaluated on TaN gated capacitors. The HfCl4/H2O reactions create surface sites that enable the chemisorption of SiCl4 in doses much smaller than the doses required for SiO2 ALD from SiCl4/H2O. The hydrolysis of Si-Cl is slower than the hydrolysis of Hf-Cl. Optimization of the hafnium silicate deposition results in a leakage current reduction of one order of magnitude for ultrascaled hafnium silicate gate stacks. At 0.9 nm EOT, a leakage current of <0.1 A/cm(2) is obtained for hafnium silicates with Hf content higher than 90%. (c) 2007 American Vacuum Society.
ISSN: 0734-2101
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Molecular Design and Synthesis
Department of Materials Engineering - miscellaneous
× corresponding author
# (joint) last author

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