Hostname: page-component-8448b6f56d-jr42d Total loading time: 0 Render date: 2024-04-24T18:07:57.241Z Has data issue: false hasContentIssue false
  • English
  • Français

Gas Cascade Amplification in Ultra-High-Resolution Environmental Scanning Electron Microcopy

Published online by Cambridge University Press:  03 September 2010

Milos Toth ,
Bradley L. Thiel  and
W. Ralph Knowles
Milos Toth*
Affiliation:
FEI Company, 5350 NE Dawson Creek Drive, Hillsboro, OR 97124, USA
Bradley L. Thiel
Affiliation:
College of Nanoscale Science and Engineering, State University of New York at Albany, 251 Fuller Road, Albany, NY 12203, USA
W. Ralph Knowles
Affiliation:
FEI Company, 5350 NE Dawson Creek Drive, Hillsboro, OR 97124, USA
*
Corresponding author. E-mail: milos.toth@FEI.com
Get access

Abstract

We describe a feedback mechanism in the gas cascade amplification process used in magnetic immersion lens environmental scanning electron microcopy (ESEM). Feedback dominates gas gain under the conditions typically used for ultra-high-resolution ESEM and gives rise to novel dependencies of the imaging signal and noise on microscope operating parameters. It is ascribed tentatively to the generation of free electrons upon de-excitation of metastable species in the gas cascade. The results have implications for optimization of ESEM systems for applications such as critical dimension metrology and real-time imaging of nanostructure growth by gas mediated electron beam induced deposition.

Keywords

low vacuum SEMenvironmental SEMgas cascade amplificationmetastablesmagnetic field enhancementfeedbacksecondary electron imaging
Type
Instrumentation and Software Developments
Information
Microscopy and Microanalysis , Volume 16 , Issue 6 , December 2010 , pp. 805 - 809
Copyright
Copyright © Microscopy Society of America 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Baker, F.S., Craven, J.P. & Donald, A.M. (2003). The environmental scanning electron microscope and its applications. In Techniques for Polymer Organisation and Morphology Characterisation, Pethrick, R.A. & Viney, C. (Eds.), pp. 111–139. West Sussex, UK: John Wiley & Sons.Google Scholar
Bogner, A., Guimaraes, A., Guimaraes, R.C.O., Santos, A.M., Thollet, G., Jouneau, P.H. & Gauthier, C. (2008). Grafting characterization of natural rubber latex particles: Wet-STEM imaging contributions. Colloid Polymer Sci 286, 1049–1059.CrossRefGoogle Scholar
Folch, A., Servat, J., Esteve, J., Tejada, J. & Seco, M. (1996). High-vacuum versus “environmental” electron beam deposition. J Vac Sci Technol B 14, 2609–2614.CrossRefGoogle Scholar
Folch, A., Tejada, J., Peters, C.H. & Wrighton, M.S. (1995). Electron-beam deposition of gold nanostructures in a reactive environment. Appl Phys Lett 66, 2080–2082.CrossRefGoogle Scholar
Hagstrum, H.D. (1978). Studies of adsorbate electronic structure using ion neutralization and photoemission spectroscopies. In Electron and Ion Spectroscopy of Solids, Fiermans, L., Vennik, J. & Dekeyser, W. (Eds.), pp. 273–323. New York: Plenum Press.CrossRefGoogle Scholar
Hahn, Y. (1997). Electron-ion recombination processes—An overview. Rep Prog Phys 60, 691–759.CrossRefGoogle Scholar
Itikawa, Y. & Mason, N. (2005). Cross sections for electron collisions with water molecules. J Phys Chem Ref Data 34, 1–22.CrossRefGoogle Scholar
Kucheyev, S.O., Toth, M., Baumann, T.F., Hamza, A.V., Ilavsky, J., Knowles, W.R., Saw, C.K., Thiel, B.L., Tileli, V., van Buuren, T., Wang, Y.M. & Willey, T.M. (2007). Structure of low-density nanoporous dielectrics revealed by low-vacuum electron microscopy and small-angle X-ray scattering. Langmuir 23, 353–356.CrossRefGoogle ScholarPubMed
Molhave, K., Madsen, D.N., Dohn, S. & Boggild, P. (2004). Constructing, connecting and soldering nanostructures by environmental electron beam deposition. Nanotechnology 15, 1047–1053.CrossRefGoogle Scholar
Molhave, K., Madsen, D.N., Rasmussen, A.M., Carlsson, A., Appel, C.C., Brorson, M., Jacobsen, C.J.H. & Boggild, P. (2003). Solid gold nanostructures fabricated by electron beam deposition. Nano Lett 3, 1499–1503.CrossRefGoogle Scholar
Noscinovsky, M. & Bhushan, B. (2008). Patterned nonadhesive surfaces: Superhydrophobicity and wetting regime transitions. Langmuir 24, 1525–1533.CrossRefGoogle Scholar
Postek, M.T. & Vladar, A.E. (2004). New application of variable-pressure/environmental microscopy to semiconductor inspection and metrology. Scanning 26, 11–17.CrossRefGoogle Scholar
Postek, M.T., Vladar, A.E., Bennett, M.H., Rice, T. & Knowles, R. (2004). Photomask dimensional metrology in the scanning electron microscope, part II: High-pressure/environmental scanning electron microscope. J Microlithog Microfab Microsyst 3, 224–231.Google Scholar
Rossi, M.P., Ye, H.H., Gogotsi, Y., Babu, S., Ndungu, P. & Bradley, J.C. (2004). Environmental scanning electron microscopy study of water in carbon nanopipes. Nano Lett 4, 989–993.CrossRefGoogle Scholar
Stelmashenko, N.A., Craven, J.P., Donald, A.M., Terentjev, E.M. & Thiel, B.L. (2001). Topographic contrast of partially wetting water droplets in environmental scanning electron microscopy. J Microsc-Oxf 204, 172–183.CrossRefGoogle ScholarPubMed
Stokes, D.J., Thiel, B.L. & Donald, A.M. (1998). Direct observation of water-oil emulsion systems in the liquid state by environmental scanning electron microscopy. Langmuir 14, 4402–4408.CrossRefGoogle Scholar
Thiel, B.L. (2004). Master curves for gas amplification in low vacuum and environmental scanning electron microscopy. Ultramicroscopy 99, 35–47.CrossRefGoogle ScholarPubMed
Thiel, B.L., Bache, I.C., Fletcher, A.L., Meredith, P. & Donald, A.M. (1997). An improved model for gaseous amplification in the environmental SEM. J Microsc-Oxf 187, 143–157.CrossRefGoogle Scholar
Thiel, B.L. & Toth, M. (2005). Secondary electron contrast in low-vacuum/environmental scanning electron microscopy of dielectrics. J Appl Phys 97, 051101.CrossRefGoogle Scholar
Thiel, B.L., Toth, M., Schroemges, R.P.M., Scholtz, J.J., van Veen, G. & Knowles, W.R. (2006). Two-stage gas amplifier for ultrahigh resolution low vacuum scanning electron microscopy. Rev Sci Instrum 77, 033705.CrossRefGoogle Scholar
Tileli, V., Knowles, W.R., Toth, M. & Thiel, B.L. (2009). Noise characteristics of the gas ionization cascade used in low vacuum scanning electron microscopy. J Appl Phys 106, 014904.CrossRefGoogle Scholar
Toth, M., Knowles, W.R. & Thiel, B.L. (2006). Secondary electron imaging of nonconductors with nanometer resolution. Appl Phys Lett 88, 023105.CrossRefGoogle Scholar
Toth, M., Lobo, C.J., Knowles, W.R., Phillips, M.R., Postek, M.T. & Vladar, A.E. (2007). Nanostructure fabrication by ultra-high-resolution environmental scanning electron microscopy. Nano Lett 7, 525–530.CrossRefGoogle ScholarPubMed
von Engel, A. (1955). Ionized Gases. Oxford, UK: Clarendon Press.Google Scholar