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Preparation and Characterization of Rare Rarth Scandate Thin Films as an Alternative gate dielectric

Published online by Cambridge University Press:  01 February 2011

Martin Wagner ,
T. Heeg ,
J. Schubert ,
St. Lenk ,
C. Zhao ,
M. Caymax  and
S. Mantl
Martin Wagner
Affiliation:
[email protected], Research Centre Juelich, Institute of Thin Films and Interfaces, Leo-Brandt-Strasse, Juelich, NRW, 52428, Germany, +49 2461 4506, +49 2461 4673
T. Heeg
Affiliation:
[email protected], Research Centre Juelich, Institute of Thin Films and Interfaces, Leo-Brandt-Strasse, Juelich, NRW, 52428, Germany
J. Schubert
Affiliation:
[email protected], Research Centre Juelich, Institute of Thin Films and Interfaces, Leo-Brandt-Strasse, Juelich, NRW, 52428, Germany
St. Lenk
Affiliation:
[email protected], Research Centre Juelich, Institute of Thin Films and Interfaces, Leo-Brandt-Strasse, Juelich, NRW, 52428, Germany
C. Zhao
Affiliation:
[email protected], IMEC, Kapeldreef 75, Leuven, N/A, 3001, Belgium
M. Caymax
Affiliation:
[email protected], IMEC, Kapeldreef 75, Leuven, N/A, 3001, Belgium
S. Mantl
Affiliation:
[email protected], Research Centre Juelich, Institute of Thin Films and Interfaces, Leo-Brandt-Strasse, Juelich, NRW, 52428, Germany
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Abstract

Rare earth scandate thin films (GdScO3 and DyScO3) were investigated with respect to future high-k applications. They were deposited on (100) silicon substrates using either pulsed laser deposition (PLD) or electron beam evaporation. The investigation of the films was done by means of Rutherford backscattering spectrometry, high-temperature X-ray-diffractometry, X-ray reflectometry, spectroscopic ellipsometry, transmission electron microscopy (TEM) and atomic force microscopy. For the electrical characterization capacitor stacks were prepared. Both materials show very promising characteristics independent from the deposition technique used. The films are stoichiometric and amorphous and exhibit a smooth surface (roughness RMS < 1 Å). The amorphous phase is stable up to 1000°C. The electrical characterization revealed featureless C-V-curves with a small hysteresis. From CET plots (CET = capacitance equivalent thickness) k-values between 20 and 23 could be extracted. The electron beam evaporation produces films with a better homogeneity and a thinner interfacial silicon dioxide and therefore a smaller CET value as confirmed by TEM. The leakage current density of the film with CET = 1.5 nm was as low as 7.7x10-4 A/cm2.

Keywords

laser ablationphysical vapor deposition (PVD)electrical properties
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 917: Symposium E – Gate Stack Scaling – Materials Selection, Role of Interfaces, and Reliability Implications , 2006 , 0917-E05-10
Copyright
Copyright © Materials Research Society 2006

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References

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