Scanning Electron Microscope Optics And Spectrometers

by Anjam Khursheed

Overview

This book contains proposals to redesign the scanning electron microscope, so that it is more compatible with other charged particle beam instrumentation and analytical techniques commonly used in surface science research. It emphasizes the concepts underlying spectrometer designs in the scanning electron microscope, and spectrometers are discussed under one common framework so that their relative strengths and weaknesses can be more readily appreciated. This is done, for the most part, through simulations and derivations carried out by the author himself.The book is aimed at scientists, engineers and graduate students whose research area or study in some way involves the scanning electron microscope and/or charged particle spectrometers. It can be used both as an introduction to these subjects and as a guide to more advanced topics about scanning electron microscope redesign.

Product Details

ISBN-13:	9789812836670
Publisher:	World Scientific Publishing Company, Incorporated
Publication date:	11/03/2010
Pages:	416
Product dimensions:	6.00(w) x 9.10(h) x 1.10(d)

Table of Contents

Preface vii

1 Conventional SEM Design 1

1.1 Introduction to the SEM 2

1.2 Basic principles of electron optics 9

1.3 The electron gun 19

1.4 Lens aberrations and primary beam probe size 24

1.5 Deflection systems 36

1.6 Quadrupole stigmators 42

1.7 SEM output signals 48

1.8 The emission hemisphere and BSE collection 51

1.9 The scattered electron energy distribution 53

1.10 The SE collection efficiency 55

1.11 Specimen charging 59

1.12 Elastic BSE imaging 61

1.13 Selected SEM image examples 64

2 Spectrometer Design Principles 71

2.1 Figures of merit 72

2.2 The SAM and the SEM 76

2.3 The retarding field analyzer 78

2.4 Deflection field analyzers 83

2.4.1 The parallel plate analyzer 83

2.4.2 The cylindrical mirror analyzer 96

2.4.3 Electric sector analyzers 101

2.4.4 Magnetic deflector analyzers 113

2.4.5 Wien filters 124

2.4.6 Magnetic collimation and time of flight spectrometers 131

3 In-lens Improvements 135

3.1 Magnetic immersion lenses 135

3.2 Magnetic semi-in-lens designs 143

3.3 Electric retarding field lenses 156

3.4 Mixed field in-lens designs 164

3.5 Selected in-lens image examples 176

4 Sub-nanometer Probe Diameters 185

4.1 Monochromators and immersion objective lenses 185

4.2 Aberration correctors 198

4.3 The helium ion microscope 218

5 Secondary Electron Spectrometers 223

5.1 Early deflection analyzers 223

5.2 Retarding field analyzers 226

5.3 Surface fields and signal-to-noise characteristics 237

5.4 Deflection/multi-channel analyzers 244

6 Full Range Deflector Spectrometer Designs 263

6.1 First-order focusing toroidal analyzers 265

6.2 A second-order focusing toroidal analyzer design 270

6.3 A modified fountain analyzer design 281

7 Full Range Parallel Energy Spectrometer Designs 287

7.1 The time-of-flight spectrometer 290

7.2 A Gaussian field magnetic sector 293

7.3 A round magnetic beam separator 301

8 Spectroscopic SEM Proposals 319

Appendix 1.0 Field Expansions 327

Appendix 1.1 Derivation of the Paraxial Equation 337

Appendix 1.2 Spherical Aberration 349

Appendix 1.3 Chromatic Aberration 365

Appendix 2 Multipole Lenses 375

Bibliography 385

Index 399