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Resolution Limits of Secondary Electron Dopant Contrast in Helium Ion and Scanning Electron Microscopy

Published online by Cambridge University Press:  12 July 2011

Mark Jepson ,
Xiong Liu ,
David Bell ,
David Ferranti ,
Beverley Inkson  and
Cornelia Rodenburg
Mark Jepson*
Affiliation:
Department of Materials, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK
Xiong Liu
Affiliation:
Carl Zeiss NTS, Carl-Zeiss-Straße 56, 73447, Oberkochen, Germany
David Bell
Affiliation:
School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
David Ferranti
Affiliation:
Carl Zeiss SMT Inc., ALIS Business Unit, One Corporation Way, Peabody, MA 01960, USA
Beverley Inkson
Affiliation:
Materials Science and Engineering, The University of Sheffield, Sheffield, S. Yorkshire S1 3JD, UK
Cornelia Rodenburg
Affiliation:
Materials Science and Engineering, The University of Sheffield, Sheffield, S. Yorkshire S1 3JD, UK
*
Corresponding author. E-mail: m.a.e.jepson@lboro.ac.uk
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Abstract

As the miniaturization of semiconductor devices continues, characterization of dopant distribution within the structures becomes increasingly challenging. One potential solution is the use of the secondary electron signal produced in scanning electron (SEMs) or helium ion microscopes (HeIMs) to image the changes in electrical potential caused by the dopant atoms. In this article, the contrast mechanisms and resolution limits of secondary electron dopant contrast are explored. It is shown that the resolution of the technique is dependent on the extent of electrical potential present at a junction and that the resolution of dopant contrast can be improved in the HeIM after an in-situ plasma cleaning routine, which causes an oxide to form on the surface altering the contrast mechanism from electrical potential to material contrast.

Keywords

scanning electron microscopy (SEM)helium ion microscopy (HeIM)dopant contrastcontrast mechanisms
Type
Helium Ion Microscopy
Information
Microscopy and Microanalysis , Volume 17 , Issue 4 , August 2011 , pp. 637 - 642
Copyright
Copyright © Microscopy Society of America 2011

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References

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