AVS 53rd International Symposium
    Thin Film Tuesday Sessions
       Session TF+SS-TuA

Invited Paper TF+SS-TuA4
Atomic Layer Deposition of Hafnium Silicate Gate Dielectric Layers

Tuesday, November 14, 2006, 3:00 pm, Room 2022

Session: Surface Functionalization for Selective Area ALD
Presenter: A. Delabie, IMEC, Belgium
Authors: A. Delabie, IMEC, Belgium
G. Pourtois, IMEC, Belgium
M. Caymax, IMEC, Belgium
S. De Gendt, IMEC, Belgium
L.-A. Ragnarsson, IMEC, Belgium
M.M. Heyns, IMEC, Belgium
Y. Fedorenko, ASM Belgium
J. Swerts, ASM Belgium
J.M. Maes, ASM Belgium
Correspondent: Click to Email
Downscaling Equivalent Oxide Thickness (EOT) by decreasing the physical thickness or increasing the permittivity of the gate dielectric is required to reach the CMOS (sub) 45 nm node performance specifications. Hafnium silicate is widely investigated as a high-k gate dielectric due to its thermodynamic stability with silicon. In this work, we study the growth mechanism of hafnium silicate Atomic Layer Deposition (ALD) by combining experiment and theory. Thorough understanding of the ALD mechanisms can contribute to improved film quality and downscaling. The hafnium silicate reaction cycle consists of well separated precursor reactions in the sequence (H@sub 2@O/HfCl@sub 4@)@sub x@/(H@sub 2@O/X)@sub y@ with X a HfCl@sub 4@ compatible Si precursor.@footnote 1@ The composition of hafnium silicate is varied by adjusting x and y. Hafnium silicate films are characterized ex-situ by Rutherford Backscattering (RBS), Time-of-Flight Secondary Ion Mass Spectroscopy (TOFSIMS) and X-Ray Photoelectron Spectroscopy (XPS). Electrical properties are evaluated on TaN gated capacitors. The interaction of ALD surface sites with the precursors is investigated by Density Functional Theory based calculations on cluster models. Our insight in the ALD reaction mechanism allows optimization of the hafnium silicate deposition, resulting in a leakage current reduction of one order of magnitude. @FootnoteText@ @footnote 1@ will be revealed at the conference .