Low Voltage Electron Microscopy E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Serie: RMS - Royal Microscopical Society
• Sprache: Englisch

Seitenzahl: 328

Veröffentlichungsjahr: 2012

Beschreibung

Part of the Wiley-Royal Microscopical Society Series, this book discusses the rapidly developing cutting-edge field of low-voltage microscopy, a field that has only recently emerged due to the rapid developments in the electron optics design and image processing.

It serves as a guide for current and new microscopists and materials scientists who are active in the field of nanotechnology, and presents applications in nanotechnology and research of surface-related phenomena, allowing researches to observe materials as never before.

Leseprobe

Table of Contents

Current and future titles in the Royal Microscopical Society— John Wiley Series

Title Page

Copyright

List of Contributors

Preface

Chapter 1: Introduction to the Theory and Advantages of Low Voltage Electron Microscopy

1.1 Introduction

1.2 Historical Perspective

1.3 Beam Interaction with Specimen—Elastic and Inelastic Scattering

1.4 Instrument Configuration

1.5 Influence of Electron Optics Aberrations at Low Voltages

1.6 SEM Imaging at Low Voltages

1.7 TEM/STEM Imaging and Analysis at Low Voltages

1.8 Conclusion

References

Chapter 2: SEM Instrumentation Developments for Low kV Imaging and Microanalysis

2.1 Introduction

2.2 The Electron Source

2.3 SEM Column Design Considerations

2.4 Beam Deceleration

2.5 Novel Detector Options and Energy Filters

2.6 Low Voltage STEM in SEM

2.7 Aberration Correction in SEM

2.8 Conclusions

References

Chapter 3: Extreme High-Resolution (XHR) SEM Using a Beam Monochromator

3.1 Introduction

3.2 Limitations in Low Voltage SEM Performance

3.3 Beam Monochromator Design and Implementation

3.4 XHR Systems and Applications

3.5 Conclusions

Acknowledgements

References

Chapter 4: The Application of Low-Voltage SEM—From Nanotechnology to Biological Research

4.1 Introduction

4.2 Specimen Preparation Considerations

4.3 Nanomaterials Applications

4.4 Beam Sensitive Materials

4.5 Semiconductor Materials

4.6 Biological Specimens

4.7 Low-Voltage Microanalysis

4.8 Conclusions

References

Chapter 5: Low Voltage High-Resolution Transmission Electron Microscopy

5.1 Introduction

5.2 So How Low is Low?

5.3 The Effect of Chromatic Aberration and Chromatic Aberration Correction

5.4 The Electron Monochromator

5.5 Theoretical Tradeoffs of Low kV Imaging

5.6 Our Experience at 40 keV LV-HREM

5.7 Examples of LV-HREM Imaging

5.8 Conclusions

References

Chapter 6: Gentle STEM of Single Atoms: Low keV Imaging and Analysis at Ultimate Detection Limits

6.1 Introduction

6.2 Optimizing STEM Resolution and Probe Current at Low Primary Energies

6.3 STEM Image Formation

6.4 Gentle STEM Applications

6.5 Discussion

6.6 Conclusion

Acknowledgements

References

Chapter 7: Low Voltage Scanning Transmission Electron Microscopy of Oxide Interfaces

7.1 Introduction

7.2 Methods and Instrumentation

7.3 Low Voltage Imaging and Spectroscopy

7.4 Summary

Acknowledgements

References

Chapter 8: What's Next? The Future Directions in Low Voltage Electron Microscopy

8.1 Introduction

8.2 Unique Low Voltage SEM and TEM Instruments

8.3 Cameras, Detectors, and Other Accessories

8.4 Conclusions

References

Index

Current and future titles in the Royal Microscopical Society— John Wiley Series

Published

Principles and Practice of Variable Pressure/Environmental Scanning Electron Microscopy (VP-ESEM)

Debbie Stokes

Aberration-Corrected Analytical Electron Microscopy

Edited by Rik Brydson

Diagnostic Electron Microscopy— A Practical Guide to Interpretation and Technique

Edited by John W. Stirling, Alan Curry & Brian Eyden

Low Voltage Electron Microscopy— Principles and Applications

Edited by David C. Bell & Natasha Erdman

Forthcoming

Atlas of Images and Spectra for Electron Microscopists

Edited by Ursel Bangert

Understanding Practical Light Microscopy

Jeremy Sanderson

Focused Ion Beam Instrumentation: Techniques and Applications

Dudley Finch & Alexander Buxbaum

Electron Beam-Specimen Interactions and Applications in Microscopy

Budhika Mendis

This edition first published 2013

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Library of Congress Cataloging-in-Publication Data

Low voltage electron microscopy : principles and applications / edited by David C. Bell, Natasha Erdman.

pages cm.

Includes index.

ISBN 978-1-119-97111-5 (hardback)

1. Electron microscopy– Technique. I. Bell, D. C. (David C.) II. Erdman, Natasha.

QH212.E4L69 2012

502.8$′25– dc23

2012033919

A catalogue record for this book is available from the British Library.

HB ISBN: 978-1-119-97111-5

List of Contributors

David C. Bell, School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02134, USA

Matthew F. Chisholm, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

Niklas Dellby, Nion Co., Kirkland, WA 98033, USA

Natasha Erdman, JEOL USA Inc., Peabody, MA 01960, USA

Alexander Henstra, FEI Company, Building AAE, PO Box 80066, 5600 KA Eindhoven, The Netherlands

Juan Carlos Idrobo, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

Robert Klie, Nanoscale Physics Group, Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA

Ondrej L. Krivanek, Nion Co., Kirkland, WA 98033, USA

Tracy C. Lovejoy, Nion Co., Kirkland, WA 98033, USA

Quentin M. Ramasse, SuperSTEM Laboratory, STFC Daresbury, Daresbury, WA4 4AD, UK

Lubomir Tuma, FEI Company, Czech Republic s.r.o. Podnikatelska 2, 612 00 Brno, Czech Republic

Gerard N.A. van Veen, FEI Company, Building AAE, PO Box 80066, 5600 KA Eindhoven, The Netherlands

Richard J. Young, FEI Company, 5350 NE Dawson Creek Drive, Hillsboro OR 97124, USA

Wu Zhou, Department of Physics & Astronomy, Vanderbilt University, Nashville, TN 37235, USA and Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

Preface

The introduction of the electron microscope in the 1930s enabled the visual confirmation that virus particles actually existed for the first time and were separate individual “living” entities. The new technology advances of electron microscopes at that time period, in particular those manufactured by Siemens in Germany and the Radio Corporation of America (RCA) enabled the routine imaging of biological tissues and cells. Further advances allowed the detailed identification and characterization of viruses, as better techniques and more powerful microscopes were developed. Electron microscopic imaging was now in a dramatic new way completely beyond the capabilities of light microscopy.

The electron microscope was invented by Max Knoll and Ernst Ruska in 1931, although there were many researchers working on the development of electron microscopes. Ernst Ruska was awarded half of the Nobel Prize for Physics in 1986 for his invention. (The other half of the Nobel Prize was divided between Heinrich Rohrer and Gerd Binnig for the STM.)

Over the years electron microscopes became more powerful in terms of resolution and by the 1970s atomic structure imaging was routinely possible. By the end of the 1990s sub-Ångstrom resolution was realized following on with the development of commercial aberration correctors. Higher power in terms resolution has been the typical benchmark by which to measure the development of the electron microscope both for the SEM and the TEM; however, with new instrumental advances it now becomes possible for greatly reduced voltage instrument to not only provide the same resolution but rather also improved contrast at the same time.

There are currently multiple texts that address either the general topics in electron microscopy (theory, operation and applications of SEM, TEM or STEM) or more specific subjects, like FIB, ESEM, bio- or polymer microscopy. The intent of this volume is to discuss the rapidly developing and cutting edge field of low voltage microscopy that has only recently become available due to the rapid developments in the electron optics design and image processing. The low voltage techniques are particularly crucial for nanotechnology and research of the surface related phenomena, allowing researches to observe materials as has never been done before. The most recent volume by Scatten and Pawley (eds) published in 2008 focuses solely on the SEM aspects of low voltage observation of biological materials. The volume presented here addresses the recent developments in theory and instrumentation and serves as a practical guide to the current and new microscopists and materials scientists who are active in the field of nanotechnology and biological imaging. The premise of this book is not to cover every single subject under the umbrella of the “low voltage microscopy” but to target principles and practical aspects of this emerging field as it pertains to the imaging techniques in widely used commercial instruments, such as SEM, TEM and STEM.

The opening chapter discusses the general concepts and principles of specimen interaction with electron beam, electron microscope instrumentation and low voltage imaging in SEM and TEM/STEM. The following Chapters (2–5) focus on SEM instrumentation and applications. Chapter 2 (N. Erdman and D.C. Bell) attempts to capture recent developments in SEM instrumentation as they pertain to low voltage microscopy and microanalysis. Chapter 3 is dedicated to development and use of monochromator in SEM (R. Young et al.). Chapter 4 discusses practical aspects of sample preparation, imaging and microanalysis for nanostructured and beam sensitive materials using low voltage. This chapter also references and shows examples of biological imaging with low voltages; however, since there exists a recent volume on this very topic, our goal is to present additional examples.

Chapters 5–7 talk about low voltage applications in TEM and STEM. Chapter 6 by D.C. Bell shows use of aberration corrected and monochromated TEM for imaging of beam sensitive materials down to 40 kV. Krivanek et al. show utilization of the “Gentle STEM” technique in Chapter 6 and R.F. Klie discusses STEM imaging and microanalysis of oxide interfaces in Chapter 7.

In the final chapter we have dedicated some discussion to other emerging techniques for low voltage imaging and analysis, such as miniature SEM columns, dedicated low voltage TEM instrumentation as well as utilization of Helium ion microscopy as an alternative to low voltage scanning electron microscopy imaging. Our hope is that current and aspiring electron microscopists, nanotechnology, materials science and biology researches that routinely use electron microscopes for their research will benefit from the theoretical and practical discussions provided in this volume.

We would like to extend our sincere thanks to all the contributors. N. Erdman would like to extend special thanks to A. Laudate of JEOL USA for fruitful discussions and providing some of the excellent graphics used in this volume. The editors would like to thank A. Lazar of Carl Zeiss Microimaging for providing us with relevant micrographs and illustrations. We would also like to thank Professor David Joy for his invaluable insight and advice.

David C. Bell, Cambridge, MANatasha Erdman, Peabody, MA

Chapter 1

Introduction to the Theory and Advantages of Low Voltage Electron Microscopy

David C. Bell1 and Natasha Erdman2

1School of Engineering and Applied Sciences, Harvard University, USA

2JEOL USA Inc., USA

1.1 Introduction

The fundamental aspects of electron microscopy all relate directly to the physics of the interactions between the electron beam and sample. These interactions have been studied extensively since the discovery of the electron by J.J. Thompson in 1897. Energetic electrons are described as “ionizing radiation”—the general term used to describe radiation that is able to ionize or remove the tightly bound inner shell electrons from a material. This is obviously an advantage for electron microscopy in that it produces a wide range of secondary signals such as secondary electrons and X-rays, but is also a disadvantage from the perspective that the sample is “ionized” by the electron beam and possibly structurally damaged, which depending on the accelerating voltage happens in a number of different ways. The advantages of using a lower accelerating voltage for the electron beam are that the energy is reduced and hence the momentum that be transferred to sample from the electron is also reduced. This, however, has the unwanted effect of reducing the possible emitted signal; although, with recent improvements in detectors, cameras and the use of aberration correctors, the signal to noise and the resolution to produce a final image can not only be maintained but are actually improved.