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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: [email protected]
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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

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References

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