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HRTEM Image Simulations for Gate Oxide Metrology

Published online by Cambridge University Press:  02 July 2020

S. Taylor
Affiliation:
Department of Materials Science and Engineering, University of California, Berkeley, CA94720 National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA94720
J. Mardinly
Affiliation:
Intel Corporation, Materials Technology Department, Santa Clara, CA95052
M.A. O'Keefe
Affiliation:
National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA94720
R. Gronsky
Affiliation:
Department of Materials Science and Engineering, University of California, Berkeley, CA94720 National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA94720
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Extract

High resolution transmission electron microscopy (HRTEM) has found extensive use in the semiconductor industry for performing device metrology and characterization. However, shrinking device dimensions (gate oxides are rapidly approaching 10Å) present challenges to the use of HRTEM for many applications, including gate oxide metrology. In this study, we performed HRTEM image simulations of a MOSFET device to examine the accuracy of HRTEM in measuring gate oxide thickness. Length measurements extracted from simulated images were compared to actual dimensions in the model structure to assess TEM accuracy. The effects of specimen tilt, specimen thickness, objective lens defocus and coefficient of spherical aberration (CS) on measurement accuracy were explored for nominal 10Å and 16Å gate oxide thicknesses.

The gate oxide was modeled as an amorphous silicon oxide situated between a gate electrode and substrate, both modeled as single crystal Si(100). Image simulations of the sandwich structure were performed in cross-section (with Si[110] parallel to beam direction) using the multislice approximation for a 200 kV microscope with Cs=0.5mm.

Type
Semiconductors
Copyright
Copyright © Microscopy Society of America

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References

References:

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4. This work was funded by the Intel Corporation. Access to computing facilities at the National Center for Electron Microscopy is gratefully acknowledged.Google Scholar