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Thin Dielectric Film Thickness Determination by Advanced Transmission Electron Microscopy

Published online by Cambridge University Press:  21 November 2003

A.C. Diebold ,
B. Foran ,
C. Kisielowski ,
D.A. Muller ,
S.J. Pennycook ,
E. Principe  and
S. Stemmer
A.C. Diebold
Affiliation:
International SEMATECH, Austin, TX, USA
B. Foran
Affiliation:
International SEMATECH, Austin, TX, USA
C. Kisielowski
Affiliation:
National Center for Electron Microscopy, Berkeley, CA, USA
D.A. Muller
Affiliation:
Bell Laboratories Lucent Technologies, Murray Hill, NJ, USA
S.J. Pennycook
Affiliation:
Oak Ridge National Laboratories, Oak Ridge, TN, USA
E. Principe
Affiliation:
Applied Materials, Santa Clara, CA, USA
S. Stemmer
Affiliation:
Materials Department, University of California-Santa Barbara, Santa Barbara, CA, USA
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Abstract

High-resolution transmission electron microscopy (HR-TEM) has been used as the ultimate method of thickness measurement for thin films. The appearance of phase contrast interference patterns in HR-TEM images has long been confused as the appearance of a crystal lattice by nonspecialists. Relatively easy to interpret crystal lattice images are now directly observed with the introduction of annular dark-field detectors for scanning TEM (STEM). With the recent development of reliable lattice image processing software that creates crystal structure images from phase contrast data, HR-TEM can also provide crystal lattice images. The resolution of both methods has been steadily improved reaching now into the sub-Ångstrom region. Improvements in electron lens and image analysis software are increasing the spatial resolution of both methods. Optimum resolution for STEM requires that the probe beam be highly localized. In STEM, beam localization is enhanced by selection of the correct aperture. When STEM measurement is done using a highly localized probe beam, HR-TEM and STEM measurement of the thickness of silicon oxynitride films agree within experimental error. In this article, the optimum conditions for HR-TEM and STEM measurement are discussed along with a method for repeatable film thickness determination. The impact of sample thickness is also discussed. The key result in this article is the proposal of a reproducible method for film thickness determination.

Keywords

thin filmsHR-TEMSTEMthickness determination
Type
Materials Applications
Information
Microscopy and Microanalysis , Volume 9 , Issue 6 , December 2003 , pp. 493 - 508
Copyright
© 2003 Microscopy Society of America

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References

REFERENCES

Batson, P.E., Dellby, N., & Krivanek, O.L. (2002). Sub-ångstrom resolution using aberration corrected electron optics. Nature 418, 617–620.CrossRefGoogle Scholar
Baumann, F.H., Chang, C.-P., Grazul, J.L., Kamgar, A., Liu, C.T., & Muller, D.A. (2000). A closer look at modern gate oxides. Mat Res Soc Symp 611, C4.1.1–C4.1.12.CrossRefGoogle Scholar
Coene, W.M.J., Thust, A., Op de Beeck, M., & Van Dyck, D. (1996). Maximum-likelihood method for focus-variation image reconstruction in high resolution transmission electron microscopy. Ultramicroscopy 64, 109–135.CrossRefGoogle Scholar
Colliex, C. & Mory, C. (1983). Quantitative aspects of scanning transmission electron microscopy. In Quantitative Electron Microscopy, Chapman, J.N. & Craven, A.J. (Eds.), pp. 149–155. Glasgow, Scotland: IOP Pub.
Diebold, A.C., Venables, D., Chabal, Y., Muller, D., Welden, M., & Garfunkel, E. (1999). Characterization and production metrology of thin gate oxide and oxy-nitride films. Mater Sci Semicond Process 2, 103–147.CrossRefGoogle Scholar
Egerton, R.F. (1989). Electron Energy Loss Spectroscopy in the Electron Microscope. New York: Plenum.
Haider, M., Rose, H., Uhlemann, S., Schwan, E., Kabius, B., & Urban, K. (1998). A spherical-aberration-corrected 200 kV transmission electron microscope. Ultramicroscopy 75, 53–60.CrossRefGoogle Scholar
Howie, A. (1979). Image contrast and localised signal selection techniques. J Microsc 117, 11–12.CrossRefGoogle Scholar
Jia, C.L. & Thust, A. (1999). Investigation of atomic displacements at a σ3 {111} twin boundary in BaTiO3 by means of phase retrieval electron microscopy. Phys Rev Lett 82, 5052–5055.CrossRefGoogle Scholar
Kabius, B., Haider, M., Uhlemann, S., Schwan, E., Urban, K., & Rose, H. (2002). First application of a spherical-aberration corrected transmission electron microscope in materials science. J Electron Microsc 51, S51–S58.CrossRefGoogle Scholar
Kirkland, E.J. (1998). Advanced Computing in Electron Microscopy. New York: Plenum.CrossRef
Kisielowski, C., Hetherington, C.J.D., Wang, Y.C., Kilaas, R., O'Keefe, M.A., & Thust, A. (2001a). Imaging columns of the light elements C, N, and O with sub-Angstrom resolution, Ultramicroscopy 89, 243–263.Google Scholar
Kisielowski, C., Jinschek, J., Mitsuishi, K., Dahmen, U., Lentzen, M., Ringnalda, J., & Fliervoet, T. (2002). Exit wave reconstruction, Cs correction and Z-contrast microscopy: Comparative strengths and limitation. In Proc. 15th Int. Conf. Electron Microscopy, Witcomb, M. (Ed.), Durban, South Africa, pp. 165–167. Onderstepoort, South Africa: The Microscopy Society of South Africa.
Kisielowski, C., Nelson, E.C., Song, C., Kilaas, R., & Thust, A. (2000). Aberration corrected lattice imaging with sub-Angstrom resolution. Microsc Microanal 6, 16–18.Google Scholar
Kisielowski, C., Principe, E., Freitag, B., & Hubert, D. (2001b). Benefits of microscopy with super resolution, Physica B 308–310, 1090–1096.Google Scholar
Krivanek, O.L., Dellby, N., & Lupini, A.R. (1999). Towards sub-angstrom electron beams. Ultramicroscopy 78, 1–11.Google Scholar
Loane, R.F., Xu, P., & Silcox, J. (1992). Incoherent imaging of zone axis crystals with ADF STEM. Ultramicroscopy 40, 121–138.CrossRefGoogle Scholar
McGibbon, A.J., Pennycook, S.J., & Jesson, D.E. (1999). Crystal structure retrieval by maximum entropy analysis of atomic resolution incoherent images. J Microsc 195, 44–57.CrossRefGoogle Scholar
Muller, D.A. (1998). Alternatives to core-loss compositional imaging. In Proc. 14th Int. Congress on Electron Microscopy, pp. 219–220. Bristol, UK: Institute of Physics Publishing.
Muller, D.A. (2000). Gate dielectric metrology using advanced TEM measurements. In Characterization and Metrology for ULSI Technology 2000, Seiler, D.G., Diebold, A.C., Shaffner, T.J., McDonald, R., Bullis, W.M., Smith, P.J. & Secula, E.M., (Eds.) pp. 500–505. Melville, NY: AIP Press.
Muller, D.A. & Neaton, J.D. (2001). Evolution of the interfacial electronic structure during thermal oxidation. In Fundamental Aspects of Silicon Oxidation, Chabal, Y. (Ed.), pp. 219–246. New York: Springer.CrossRef
Muller, D.A., Sorsch, T., Moccio, S., Baumann, F.H., Evans-Lutterodt, K., & Timp, G. (1999). The electronic structure at the atomic scale of ultrathin gate oxides. Nature 399, 758–761.CrossRefGoogle Scholar
Nellist, P.D. & Pennycook, S.J. (1998a). Accurate structure determination from image reconstruction in ADF STEM. J Microsc 190, 159–170.Google Scholar
Nellist, P.D. & Pennycook, S.J. (1998b). Sub-angstrom resolution by underfocused incoherent transmission electron microscopy. Phys Rev Lett 81, 4156–4159.Google Scholar
O'Keefe, M.A., Herington, C.J.D., Wang, Y.C., Nelson, E.C., Turner, J.H., Kisielowski, C., Malm, J.-O., Mueller, R., Ringnalda, J., Pan, M., & Thust, A. (2001). Sub-Angstrom high resolution transmission electron microscopy at 300 keV. Ultramicroscopy 89, 215–241.CrossRefGoogle Scholar
Pantel, R., Sondergard, E., Delille, D., & Kwakman, L.F.Tz. (2001). Quantitative thickness measurements of thin oxides using low energy loss filtered TEM imaging. Microsc Microanal 7 (Suppl. 2), 560–561.Google Scholar
Pantelides, S.T., Ramamoorthy, M., Rashkeev, S., Buczko, R., Duscher, G., & Pennycook, S.J. (2001). Local and global bonding at the Si-SiO2 interface. In Fundamental Aspects of Silicon Oxidation. Chabal, Y.J. (Ed.), pp. 193–218. Berlin: Springer-Verlag.CrossRef
Pennycook, S.J. (1997). Scanning transmission electron microscopy: Z-contrast. In Handbook of Microscopy, Amelinckx, S., Van Tendeloo, G., Van Dyck, D. & Van Landuyt, J. (Eds.), pp. 595–620. Weinheim, Germany: VCH Publishers.
Pennycook, S.J. & Boatner, L.A. (1988). Chemically sensitive structure imaging with a scanning transmission electron microscope. Nature 336, 565–567.CrossRefGoogle Scholar
Pennycook, S.J. & Jesson, D.E. (1990). High-resolution incoherent imaging of crystals. Phys Rev Lett, 64, 938–941.CrossRefGoogle Scholar
Pennycook, S.J. & Jesson, D.E. (1991). High-resolution Z-contrast imaging of crystals. Ultramicroscopy 37, 14–38.CrossRefGoogle Scholar
Pennycook, S.J., Lupini, A.R., & Nellist, P.D. (2002). The ultimate resolution in aberration-corrected STEM. Microsc Microanal 8 (Suppl. 2), 16–17.Google Scholar
Pennycook, S.J., Rafferty, B., & Nellist, P.D. (2000). Towards Z-contrast imaging in an aberration-corrected STEM. Microsc Microanal 6 (Suppl. 2), 106–107.Google Scholar
Perovic, D.D., Rossow, C.J., & Howie, A. (1993). Imaging elastic strains in high-angle annular dark field scanning transmission electron microscopy. Ultramicroscopy 52, 353–359.CrossRefGoogle Scholar
Principe, E., Hegedus, A., Chua, T.C., & Olson, C. (2001). Hyper thin nitrided gate oxide characterization methodology, presented at the Quantitative Surface Analysis Conference, San Jose: AVS.
Principe, E., Watson, D.G., & Kisielowski, C. (2002). Advancements in the characterization of “hyper-thin” oxynitride gate dielectrics through exit wave reconstruction HRTEM and XPS. In Microelectronic Failure Analysis Desk Reference 2002 Supplement pp. 59–68. Materials Park, Ohio: ASM International.
Puetter, R.C. & Yahil, A. (1999). The Pixon method of image reconstruction. In Astronomical Data Analysis Software and Systems VIII, Mehringer, D.M., Plante, R.L. & Roberts, D.A. (Eds.), Vol. 172, pp. 307–316. San Francisco: ASP.
Rau, W.D. & Lichte, H. (1999). High resolution off-axis electron holography. In Introduction to Electron Holography, Volkl, E., Allard, L.F. & Joy, D.C. (Eds.), pp. 201–229. New York: Kluwer Academic.CrossRef
Reimer, L. (1997). Transmission Electron Microscopy: Physics of Image Formation and Microanalysis. Springer Series in Optical Science Volume 36. New York: Springer.CrossRef
Ross, F.M. & Stobbs, W.M. (1991). A study of the initial stages of the oxidation of silicon using the Fresnel Method. Philos Mag A 63, 1–36.Google Scholar
Shin, D.H., Kirkland, E.J., & Silcox, J. (1989). Annular dark field electron microscope images with better than 2 Å resolution at 100 kV. Appl Phys Lett 55, 2456–2458.CrossRefGoogle Scholar
Silcox, J., Xu, P., & Loane, R.L. (1992). Resolution limits in annular dark field STEM. Ultramicroscopy 47, 173–186.CrossRefGoogle Scholar
Taylor, S., Mardinly, J., O'Keefe, M.A., & Gronsky, R. (2000). HRTEM image simulations for gate oxide metrology. In Characterization and Metrology for ULSI Technology 2000, Seiler, D.G., Diebold, A.C., Shaffner, T.J., McDonald, R., Bullis, W.M., Smith, P.J. & Secula, E.M. (Eds.), pp. 130–133. AIP conference Proceedings 550. Melville, NY: AIP Press.
Thust, A., Coene, W.M.J., Op de Beeck, M., & Van Dyck, D. (1996). Focal-series reconstruction in HRTEM: Simulation studies on non-periodic objects. Ultramicroscopy 64, 211–230.CrossRefGoogle Scholar
van Dyck, D. & Chen, J.H. (1999). A simple theory for dynamical electron diffraction in crystals. Solid State Communications 109, 501–505.CrossRefGoogle Scholar
Wang, Y.C., Fitzgerald, A., Nelson, E.C., Song, C., O'Keefe, M.A., & Kisielowski, C. (1999). Correction of the 3-fold astigmatism and lattice imaging with information below 100 pm. Microsc Microanal 5, 822–824.Google Scholar
Wang, Z.L. (1997). Lattice imaging using plasmon energy-loss electrons in an energy-filtered transmission electron microscope. Ultramicroscopy 67, 105–111.CrossRefGoogle Scholar