Low Voltage Electron Microscopy

List of Contributors ix
Preface xi
1 Introduction to the Theory and Advantages of Low VoltageElectron Microscopy 1
David C. Bell and Natasha Erdman
1.1 Introduction 1
1.2 Historical Perspective 2
1.3 Beam Interaction with Specimen--Elastic and InelasticScattering 3
1.4 Instrument Configuration 11
1.5 Influence of Electron Optics Aberrations at Low Voltages12
1.6 SEM Imaging at Low Voltages 16
1.7 TEM/STEM Imaging and Analysis at Low Voltages 26
1.8 Conclusion 27
References 28
2 SEM Instrumentation Developments for Low kV Imaging andMicroanalysis 31
Natasha Erdman and David C. Bell
2.1 Introduction 31
2.2 The Electron Source 33
2.3 SEM Column Design Considerations 36
2.4 Beam Deceleration 41
2.5 Novel Detector Options and Energy Filters 43
2.6 Low Voltage STEM in SEM 48
2.7 Aberration Correction in SEM 50
2.8 Conclusions 53
References 53
3 Extreme High-Resolution (XHR) SEM Using a BeamMonochromator 57
Richard J. Young, Gerard N.A. van Veen, Alexander Henstraand Lubomir Tuma
3.1 Introduction 57
3.2 Limitations in Low Voltage SEM Performance 58
3.3 Beam Monochromator Design and Implementation 59
3.4 XHR Systems and Applications 63
3.5 Conclusions 69
Acknowledgements 70
References 70
4 The Application of Low-Voltage SEM--FromNanotechnology to Biological Research 73
Natasha Erdman and David C. Bell
4.1 Introduction 73
4.2 Specimen Preparation Considerations 74
4.3 Nanomaterials Applications 76
4.4 Beam Sensitive Materials 84
4.5 Semiconductor Materials 85
4.6 Biological Specimens 87
4.7 Low-Voltage Microanalysis 91
4.8 Conclusions 92
References 93
5 Low Voltage High-Resolution Transmission ElectronMicroscopy 97
David C. Bell
5.1 Introduction 97
5.2 So How Low is Low? 99
5.3 The Effect of Chromatic Aberration and Chromatic AberrationCorrection 100
5.4 The Electron Monochromator 103
5.5 Theoretical Tradeoffs of Low kV Imaging 105
5.6 Our Experience at 40 keV LV-HREM 109
5.7 Examples of LV-HREM Imaging 110
5.8 Conclusions 114
References 116
6 Gentle STEM of Single Atoms: Low keV Imaging and Analysisat Ultimate Detection Limits 119
Ondrej L. Krivanek, Wu Zhou, Matthew F. Chisholm, JuanCarlos Idrobo, Tracy C. Lovejoy, Quentin M. Ramasse and NiklasDellby
6.1 Introduction 119
6.2 Optimizing STEM Resolution and Probe Current at Low PrimaryEnergies 121
6.3 STEM Image Formation 128
6.4 Gentle STEM Applications 135
6.5 Discussion 154
6.6 Conclusion 156
Acknowledgements 157
References 157
7 Low Voltage Scanning Transmission Electron Microscopy ofOxide Interfaces 163
Robert Klie
7.1 Introduction 163
7.2 Methods and Instrumentation 166
7.3 Low Voltage Imaging and Spectroscopy 168
7.4 Summary 180
Acknowledgements 180
References 180
8 What's Next? The Future Directions in Low VoltageElectron Microscopy 185
David C. Bell and Natasha Erdman
8.1 Introduction 185
8.2 Unique Low Voltage SEM and TEM Instruments 186
8.3 Cameras, Detectors, and Other Accessories 192
8.4 Conclusions 198
References 199
Index 201