Skip to main content Accessibility help
×
×
Home

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

  • Milos Toth (a1), Bradley L. Thiel (a2) and W. Ralph Knowles (a1)

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.

Copyright

Corresponding author

Corresponding author. E-mail: milos.toth@FEI.com

References

Hide All
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. 111139. West Sussex, UK: John Wiley & Sons.
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, 10491059.
Folch, A., Servat, J., Esteve, J., Tejada, J. & Seco, M. (1996). High-vacuum versus “environmental” electron beam deposition. J Vac Sci Technol B 14, 26092614.
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, 20802082.
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. 273323. New York: Plenum Press.
Hahn, Y. (1997). Electron-ion recombination processes—An overview. Rep Prog Phys 60, 691759.
Itikawa, Y. & Mason, N. (2005). Cross sections for electron collisions with water molecules. J Phys Chem Ref Data 34, 122.
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, 353356.
Molhave, K., Madsen, D.N., Dohn, S. & Boggild, P. (2004). Constructing, connecting and soldering nanostructures by environmental electron beam deposition. Nanotechnology 15, 10471053.
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, 14991503.
Noscinovsky, M. & Bhushan, B. (2008). Patterned nonadhesive surfaces: Superhydrophobicity and wetting regime transitions. Langmuir 24, 15251533.
Postek, M.T. & Vladar, A.E. (2004). New application of variable-pressure/environmental microscopy to semiconductor inspection and metrology. Scanning 26, 1117.
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, 224231.
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, 989993.
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, 172183.
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, 44024408.
Thiel, B.L. (2004). Master curves for gas amplification in low vacuum and environmental scanning electron microscopy. Ultramicroscopy 99, 3547.
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, 143157.
Thiel, B.L. & Toth, M. (2005). Secondary electron contrast in low-vacuum/environmental scanning electron microscopy of dielectrics. J Appl Phys 97, 051101.
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.
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.
Toth, M., Knowles, W.R. & Thiel, B.L. (2006). Secondary electron imaging of nonconductors with nanometer resolution. Appl Phys Lett 88, 023105.
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, 525530.
von Engel, A. (1955). Ionized Gases. Oxford, UK: Clarendon Press.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Microscopy and Microanalysis
  • ISSN: 1431-9276
  • EISSN: 1435-8115
  • URL: /core/journals/microscopy-and-microanalysis
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Keywords

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed