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On the Nature of Weak Spots in High-k Layers Submitted to Anneals

Published online by Cambridge University Press:  28 July 2011

J. Pétry ,
W. Vandervorst ,
O. Richard ,
T. Conard ,
P. DeWolf ,
V. Kaushik ,
A. Delabie  and
S. Van Elshocht
J. Pétry
Affiliation:
also KULeuven, INSYS, Kasteelpark Arenberg, 3001 Heverlee, Belgium
W. Vandervorst
Affiliation:
also KULeuven, INSYS, Kasteelpark Arenberg, 3001 Heverlee, Belgium
O. Richard
Affiliation:
IMEC, 75 Kapeldreef, 3001 Heverlee, Belgium
T. Conard
Affiliation:
IMEC, 75 Kapeldreef, 3001 Heverlee, Belgium
P. DeWolf
Affiliation:
VEECO Instruments, 11 - BP 43 rue Marie Poussepin,91412 Dourdan, France
V. Kaushik
Affiliation:
Motorola Inc., 75 Kapeldreef, 3001 Heverlee, Belgium
A. Delabie
Affiliation:
IMEC, 75 Kapeldreef, 3001 Heverlee, Belgium
S. Van Elshocht
Affiliation:
IMEC, 75 Kapeldreef, 3001 Heverlee, Belgium
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Abstract

In the path to the introduction of high-k dielectric into IC components, a large number of challenges have still to be solved. Some of the major issues concern the low mobility of carriers and the reliability of the devices. Trapped charges in the stack have been identified as being the cause of these issues. With this in mind, we used Conducting Atomic Force Microscopy, combined with physical analysis to understand the nature of these charges. In this contribution, we have studied the uniformity of thin HfO2 layers, with and without anneal. The Conducting Atomic Force microscopy measurements show spots of higher conductivity. Recording local IV's in those ‘weak’ spots suggests that they consist of positive charge. On the other hand, XPS and ToFSIMS analysis show a diffusion of the interfacial SiO2 upwards into the high-k layer. Finally, the comparison of samples with differing high-k material and crystallinity indicates a strong correlation between the weak spots and the presence of silicon in the film.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 811: Symposia D/E – Integration of Advanced Micro-and Nanelectronic Devices-Critical Issues and Solutions , 2004 , D6.10
Copyright
Copyright © Materials Research Society 2004

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