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Contrast Mechanisms and Image Formation in Helium Ion Microscopy

Published online by Cambridge University Press:  16 March 2009

David C. Bell
David C. Bell*
Affiliation:
School of Engineering and Applied Sciences and the Center for Nanoscale Systems, Harvard University, Cambridge, MA 02138, USA
*
E-mail: dcb@deas.harvard.edu
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Abstract

The helium ion microscope is a unique imaging instrument. Based on an atomic level imaging system using the principle of field ion microscopy, the helium ion source has been shown to be incredibly stable and reliable, itself a remarkable engineering feat. Here we show that the image contrast is fundamentally different to other microscopes such as the scanning electron microscope (SEM), although showing many operational similarities due to the physical ion interaction mechanisms with the sample. Secondary electron images show enhanced surface contrast due the small surface interaction volume as well as elemental contrast differences, such as for nanowires imaged on a substrate. We present images of nanowires and nanoparticles for comparison with SEM imaging. Applications of Rutherford backscattered ion imaging as a unique and novel imaging mechanism are described. The advantages of the contrast mechanisms offered by this instrument for imaging nanomaterials are clearly apparent due to the high resolution and surface sensitivity afforded in the images. Future developments of the helium ion microscope should yield yet further improvements in imaging and provide a platform for continued advances in microscope science and nanoscale research.

Keywords

He ion microscopesecondary electron imageORIONRutherford backscattered ion imageSEM
Type
Image Formation and Analysis
Information
Microscopy and Microanalysis , Volume 15 , Issue 2 , April 2009 , pp. 147 - 153
Copyright
Copyright © Microscopy Society of America 2009

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References

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