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Aqueous chemical solution deposition of ultrathin lanthanide oxide dielectric films

Published online by Cambridge University Press:  31 January 2011

An Hardy
Hasselt University, Institute for Materials Research, Laboratory of Inorganic and Physical Chemistry, B-3590 Diepenbeek, Belgium; and XIOS Hogeschool Limburg, Department of Industrial Sciences and Technology (IWT), Universitaire Campus, B-3590 Diepenbeek, Belgium
Sven Van Elshocht
IMEC vzw, B-3001 Heverlee, Belgium
Jan D’Haen
IMEC vzw, Division IMOMEC, B-3590 Diepenbeek, Belgium; and Hasselt University, Institute for Materials Research, B-3590 Diepenbeek, Belgium
Olivier Douhéret
IMEC vzw, Division IMOMEC, B-3590 Diepenbeek, Belgium
Stefan De Gendt
IMEC vzw, B-3001 Heverlee, Belgium; and KULeuven, Department of Chemistry, B-3001 Heverlee, Belgium
Christoph Adelmann
IMEC vzw, B-3001 Heverlee, Belgium
Matty Caymax
IMEC vzw, B-3001 Heverlee, Belgium
Thierry Conard
IMEC vzw, B-3001 Heverlee, Belgium
Thomas Witters
IMEC vzw, B-3001 Heverlee, Belgium
Hugo Bender
IMEC vzw, B-3001 Heverlee, Belgium
Olivier Richard
IMEC vzw, B-3001 Heverlee, Belgium
Marc Heyns
IMEC vzw, B-3001 Heverlee, Belgium
Marc D’Olieslaeger
IMEC vzw, Division IMOMEC, B-3590 Diepenbeek, Belgium, and Hasselt University, Institute for Materials Research, B-3590 Diepenbeek, Belgium
Marlies K. Van Bael*
Hasselt University, Institute for Materials Research, Laboratory of Inorganic and Physical Chemistry, B-3590 Diepenbeek, Belgium; and IMEC vzw, Division IMOMEC, B-3590 Diepenbeek, Belgium
Jules Mullens*
Hasselt University, Institute for Materials Research, Laboratory of Inorganic and Physical Chemistry, B-3590 Diepenbeek, Belgium
a)Address all correspondence to these authors. e-mail:
b)Address all correspondence to these authors. e-mail:
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Ultrathin lanthanide (Nd, Pr, Eu, Sm) oxide films with functional dielectric properties down to 3.3 nm thickness were deposited by aqueous chemical solution deposition (CSD) onto hydrophilic SiO2/Si substrates. Precursor solutions were prepared from the oxides via an intermediate, solid Ln(III)citrate. A film heat treatment scheme was derived from thermogravimetric analysis of the precursor gels, showing complete decomposition by 600 °C. Crystalline phase formation in the films depended on the lanthanide, annealing temperature, and citric acid content in the precursor. Through variation of the precursor concentration and number of deposited layers, thickness series of uniform films were obtained down to ∼3 nm. The film uniformity was demonstrated both by atomic force microscopy and cross-section transmission electron microscopy. The lanthanide oxide films possessed good dielectric properties. It was concluded that aqueous CSD allows deposition of uniform ultrathin films and may be useful for the evaluation of new high-k candidate materials.

Copyright © Materials Research Society 2007

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