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Mapping of Process-Induced Dopant Redistributions by Electron Holography

Published online by Cambridge University Press:  01 August 2004

Wolf-Dieter Rau
Affiliation:
LEO Electron Microscopy GmbH, Carl Zeiss SMT AG, Carl Zeiss Str. 56, D-73447 Oberkochen, Germany
Alexander Orchowski
Affiliation:
LEO Electron Microscopy GmbH, Carl Zeiss SMT AG, Carl Zeiss Str. 56, D-73447 Oberkochen, Germany
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Abstract

We present and review dopant mapping examples in semiconductor device structures by electron holography and outline their potential applications for experimental investigation of two-dimensional (2D) dopant diffusion on the nanometer scale. We address the technical challenges of the method when applied to transistor structures with respect to quantification of the results in terms of the 2D pn junction potential and critically review experimental boundary conditions, accuracy, and potential pitfalls. By obtaining maps of the inner electrostatic potential before and after anneals typically used in device processing, we demonstrate how the “vertical” and “lateral” redistribution of boron during device fabrication can directly be revealed. Such data can be compared with the results of process simulation to extract the fundamental parameters for dopant diffusion in complex device structures.

Type
Materials Applications
Copyright
© 2004 Microscopy Society of America

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References

REFERENCES

Allard, L.F. & Völkl, E. (1999). Optical characteristics of a holography microscope. In Introduction to Electron Holography, Völkl, E., Allard, L.F. & Joy, D.C. (Eds.), pp. 5686. New York: Kluwer Academics/Plenum Publishers.
Frabboni, S., Matteucci, G., Pozzi, G., & Vanzi, M. (1985). Electron holographic observation of the electrostatic field associated with thin reverse-biased pn junctions. Phys Rev Lett 55, 21962199.Google Scholar
Frost, B.G., Völkl, E., & Allard, L.F. (1996). An improved mode of operation of a transmission electron microscope for wide field off-axis holography. Ultramicroscopy 63, 1520.Google Scholar
Gajdardziska-Josifovska, M. & Carim, A.H. (1999). Applications of electron holography. In Introduction to Electron Holography, Völkl, E., Allard, L.F. & Joy, D.C. (Eds.), pp. 267293. New York: Kluwer Academics/Plenum Publishers.
Gajdardziska-Josifovska, M., McCartney, M.R., de Ruijter, W.J., Smith, D.J., Weiss, J.K., & Zuo, J.M. (1993). Accurate measurements of mean inner potential of crystal wedges using digital electron holograms. Ultramicroscopy 50, 285299.Google Scholar
Gribelyuk, M.A., McCartney, M.R., Li, J., Murthy, C.S., Ronsheim, P., Doris, B., McMurray, J.S., Hegde, S., & Smith, D.J. (2002). Mapping of electrostatic potential in deep submicron CMOS devices by electron holography. Phys Rev Lett 89, 255021255024.Google Scholar
ITRS: International Technology Roadmap for Semiconductors. (2001). http://www.public.itrs.net.
Knoll, D., Heinemann, B., Osten, H.-J., Ehwald, K.-E., Tillack, B., Schley, P., Barth, R., Matthes, M., Park, K.S., Kim, J., & Winkler, W. (1998). Si/SiGe:C Heterojunction bipolar transistors in an epi-free well, single-polysilicon technology. In IEDM Technology Digest 1998, pp. 703706. San Francisco, CA: IEEE.
Lehmann, M., Brand, K., & Lichte, H. (2002). Holographic setup for 2D dopant profiling using the Lorentz lens. Microsc. Microanal. 8(Suppl. 2), 536537 CD.Google Scholar
Lehmann, M. & Lichte, H. (2002). Tutorial on electron holography. Microsc Microanal 8, 447466.Google Scholar
Li, J., McCartney, M.R., Dunin-Borkowski, R.E., & Smith, D.J. (1999). Determination of mean inner potential of germa-nium using off-axis electron holography. Acta Cryst A 55, 652658.Google Scholar
Li, J., McCartney, M.R., & Smith, D.J. (2003). Semiconductor dopant profiling by off-axis electron holography. Ultramicroscopy 94, 149161.Google Scholar
Lichte, H. (1996). Electron holography: Optimum position of the electron biprism in the electron microscope. Ultramicroscopy 64, 7986.Google Scholar
Lichte, H. (1997). Electron holography methods. In Handbook of Microscopy, Amelincks, S., van Dyck, D., van Landuyt, J. & van Tendeloo, G. (Eds.), pp. 515536. Weinheim: Wiley-VCH.
McCartney, M.R., Gribelyuk, M.A., Li, J., Ronsheim, P., McMurray, J.S., & Smith, D.J. (2002). Quantitative analysis of one-dimensional dopant profile by electron holography. Appl Phys Lett 80, 32133215.Google Scholar
McCartney, M.R., Smith, D.J., Hull, R., Bean, J.C., Völkl, E., & Frost, B. (1994). Direct observation of potential distribution across Si/Si p-n junctions using off-axis electron holography. Appl Phys Lett 65, 26032605.Google Scholar
Orchowski, A., Rau, W.-D., Rücker, H., Heinemann, B., Schwander, P., Tillack, B., & Ourmazd, A. (2002). Local electrostatic potential and process-induced boron redistribution in patterned Si/SiGe/Si heterostructures. Appl Phys Lett 80, 25562558.Google Scholar
Rau, W.-D., Baumann, F.H., Vuong, H.-H., Heinemann, B., Höppner, W., Rafferty, C.S., Rücker, H., Schwander, P., & Ourmazd, A. (1998). Two-dimensional dopant profiling of deep submicron MOS devices by electron holography. In IEDM Technology Digest 1998, pp. 713716. San Francisco, CA: IEEE.
Rau, W.-D., Schwander, P., Baumann, F.H., Höppner, W., & Ourmazd, A. (1999). Two-dimensional mapping of the electrostatic potential in transistors by electron holography. Phys Rev Lett 82, 26142617.Google Scholar
Rau, W.-D., Schwander, P., & Ourmazd, A. (2000). Two-dimensional mapping of pn junctions by electron holography. Phys Stat Sol B 222, 213217.Google Scholar
Thesen, A.E., Frost, G.B., & Joy, D.C. (2003). Holographic voltage profiling on 75 nm gate architecture CMOS devices, Ultramicroscopy 94, 277281.Google Scholar
Twitchett, A.C., Dunin-Borkowski, R.E., & Midgley, P.A. (2002). Quantitative electron holography of biased semiconductor devices. Phys Rev Lett 88, 23830212383024.Google Scholar
Völkl, E. & Lehmann, M. (1999). The reconstruction of off-axis electron holograms. In Introduction to Electron Holography, Völkl, E., Allard, L.F. & Joy, D.C. (Eds.), pp. 125151. New York: Kluwer Academics/Plenum Publishers.
Wang, Y.C., Chou, T.M., Libera, M., & Kelly, T.F. (1997). Transmission electron holography of silicon nanospheres with surface oxide layers. Appl Phys Lett 70, 12961298.Google Scholar