Electron Microscopy In Material Science

Contents

Contributors

Foreword

Introduction

Opening Lecture

P. B. Hirsch : The Impact of Transmission Electron Microscopy in the Science of Materials


1. Historical Introduction 3


2. Application of TEM in Materials Science


2.1. Dislocation Theory


2.2. Mechanical Properties


2.3. Point Defects and Dislocations: Quench-Hardening


2.4. Radiation Damage


2.5. Phase Transformations


2.6. Kinetic Studies


2.7. Surface Layer Studies


2.8. Magnetic Properties


2.9. Miscellaneous Applications


3. Conclusions


4. Future Prospects

References

Electron Optics and Instrumentation

A. Septier: Geometrical Electron Optics


1. Electrostatic Lenses


1.1. Introduction


1.2. Equation of Motion in an Electrostatic Lens


1.3. The Properties of Some Electrostatic Lenses


1.4. Aberrations of Electrostatic Lenses


2. Magnetic Lenses


2.1. Principle


2.2. The Motion of Particles in a Magnetic Lens


2.3. Optical Properties


2.4. Aberrations of Magnetic Lenses


2.5. Magnetic Lenses for High Voltage Microscopes


3. Quadrupole Lenses


3.1. Introduction


3.2. Optical Properties of Quadrupole Lenses


3.3. Quadrupole Systems Suitable as Objectives


3.4. The Aperture Aberrations of Quadrupole Systems and their Correction


3.5. Correction of Chromatic Aberration


4. Prisms Optics


4.1. Introduction


4.2. Simple Prisms


4.3 Magnetic Prisms


4.4. Electrostatic Prisms

References

A. Septier: Problems on Geometrical Electron Optics


1. Electrostatic Lenses

l.l. Problems


1.2. Solutions


2. Round Magnetic Lenses


2.1. Problems


2.2. Solutions


3. Quadrupole Lenses


3.1. Problems


3.2. Solutions


4. Prisms


4.1. Problems


4.2. Solutions

R. Castaing: Secondary Ion Microanalysis and Energy-Selecting Electron Microscopy


1. Dispersive Microscopy Using Magnetic Prisms


1.1. Introduction


1.2. First-Order Focussing Properties of a Simple Magnetic Prism


1.3. The Dispersive System of the Energy-Selecting Electron Microscope


1.4. The Dispersive System of the Secondary Ion Microanalyzer

References (Section 1)


2. Some Applications of the Magnetic Filtering of Energies in Electron Microscopy


2.1. Introduction


2.2. The Various Scattering Processes that an Electron May Undergo in a Solid Sample


2.3. Energy Selection and « Colour » Electron Microscopy


2.4. Experimental Investigation of the Coherency of the Interaction of Fast Electrons with a Solid Sample

References (Section 2)


3. Ion emission Microanalysis


3.1. Introduction


3.2. General Description of the Secondary Ion Microanalyzer


3.3. Possibilities and Limitations of Secondary Ion Microanalysis


3.4. The Various Processes Involved in Secondary Ion Emission


3.5. The Alternative Procedure Using an Ion Microprobe


3.6. The Main Features of the « Kinetic » Process


3.7. Some Applications of Secondary Ion Microanalysis

References (Section 3)

Α. V. Crewe : High Intensity Electron Sources and Scanning Electron Microscopy


1. Field emission and an electron Gun


1.1. Introduction


1.2. Field Emission as an Electron Source


1.3. The Electron Gun


1.4. Optical Properties of the Electron Gun

References (Section 1)


2. Microscope Design Using Field Emission Gun


2.1. Simple Scanning Microscope


2.2. High Resolution Microscope

References (Section 2)


3. Contrast Mechanisms in a High Resolution Scanning Microscope


3.1. Mechanisms Identical to the Conventional Microscope


3.2. Mechanisms Peculiar to the Scanning Microscope

References (Section 3)

U. Valdrè and M. J. Goringe: Special Electron Microscope Specimen Stages


1. Introduction


2. Generalities and Definitions


3. Examples of Practical Tilting Stages


4. Specimen Orientation Determination


5. Combined Double Tilting Stages


5.1. Double Tilting and Rotation


5.2. Double Tilting and Lifting


5.3. Double Tilting and Deformation


5.4. Double Tilting and Heating


5.5. Double Tilting and Cooling


6. Ultra-high Vacuum Stages


7. Multipurpose Stages


8. Conclusions

References

K.-H. Hermann, D. Krahl, A. Kubler, K.-H. Muller, V. Rindfleisch: Image Recording with Semiconductor Detectors and Video Amplification Devices


1. Image Recording with Semiconductor Detectors


1.1. Introduction


1.2. Measuring Device with Semiconductor Detectors

References (Section 1)


2. Image Amplification with Television Methods


2.1. Introduction


2.2. Method

References (Section 2)

Diffraction Contrast and Applications

A. Howie: The Theory of Electron Diffraction Image Contrast


1. Introduction


2. Foundations of Diffraction Theory


3. Simplified Theories of Wave Propagation in Crystals


4. Formal Theory of Elastic Scattering in Perfect Crystals


5. Anomalous Absorption Effects


6. Experimental Verification of Perfect Crystal Dynamical Theory


7. Formal Theory of Elastic Scattering in Imperfect Crystals


8. Inelastic Scattering


9. Conclusions

References

R. Gevers: Application of Electron Diffraction


1. Images of planar defects in electron transmission microscopy


1.1. Model of Planar Defect


1.2. α and δ Fringes


1.3. Calculation of the Amplitudes


1.4. Influence of Absorption


1.5. Properties of Stacking Fault Images in Thick Crystal


1.6. Properties of δ-fringe Pattern


1.7. Examples of Application


1.8. Moiré Fringes


1.9. Observations

References (Section 1) 343


2. Fine Structure of Diffraction Spots


2.1. General Formulation


2.2. The Different Beams


2.3. The Diffraction Pattern of a Fringe Pattern


2.4. Stacking Fault: Two-Beam Case


2.5. One-Beam Kinematical Approximation


2.6. Influence of Anomalous Absorption


2.7. Observations


2.8. Two-beam Kinematical Approximation

References (Section 2)

L. M. Brown: Metallurgical Information from Electron Micrographs


1. Introduction


2. Contrast from Planar Defects


2*1. Stacking Faults


2*2. More General Discussion of Contrast from Planar Defects


3. Contrast from Dislocations


4. Contrast from Inclusions


4*1. Structure Factor Contrast


4*2. Interface Contrast


4*3. Strain Contrast

References 385

M. J. Makin : The Application of Electron Microscopy to Radiation Damage Studies


1. The damage process 389


1.1. The Relevance of Radiation Damage Studies


1.2. The Primary Event


1.3. Collision Cascades


1.4. Crystal Lattice Effects


1.5. Thermal Spikes

References (Section 1)


2. The Nature of the Damage: Basic Effects


2.1. General


2.2. Point Defects


2.3. The Formation of Clusters During Irradiation

References (Section 2)


3. The Nature of the Damage: Technological Effects


3.1. Introduction


3.2. Radiation Growth in Uranium


3.3. Radiation Hardening


3.4. Impurity Effects


3.5. Summary

References (Section 3)


4. Radiation Damage Studies in High Voltage Microscopes


4.1. Introduction


4'2. The Displacement Process


4'3. The Effect of Electron Irradiation at High Voltages

References (Section 4)

M. J. Goringe: Computing Methods


1. Introduction


2. Perfect Crystals and Faults: 2-beam Approximation


2.1. Perfect Crystals


2.2. Scattering Matrix for Perfect Crystal


2.3. Faulted Crystals by Scattering Matrices


2.4. Moiré Fringes


2.5. Lattice Fringes


3. Perfect Crystal and Faults: «-Beam


3.1. Wave Matching


3.2. Perfect Crystal


3.3. Planar Faults


3.4. Modified Extinction Distances


4. Imperfect Crystals


4.1. ψο,ψg Formulation (2-beam)


4.2. ψ formulation («-beam)


4.3. Bloch Wave Formulation


5. Comparison of Model Calculations with Micrographs


5.1. Line Profiles


5.2. Two-Dimensional Displays


6. Time-Saving Techniques


7. Uniqueness of Computed Results


8. Sources of Useful Parameters


9. References to Alternative Formulations

Acknowledgements

References

M. J. Goringe and C. R. Hall: Typical Problems in Electron Microscopy 4


1. Introduction


2. Problems


3. Solutions

References

Transfer of Image Information and Phase Contrast

F. A. Lenz: Transfer of Image Information in the Electron Microscope


1. General Theory


2. Amplitude Transfer and Contrast Transfer Function


3. Zonal Plates and Other Interventions in the Back Focal Plane of the Objective


4. The Effects of Illumination on Image Transfer

References

F. Thon : Phase Contrast Electron Microscopy


1. Conventional Phase Contrast Imaging


1.1. Introduction


1.2. Theory


1.3. Experimental Demonstrations

References (Section 1)


2. High resolution Microscopy Using Special Apertures


2.1. Introduction


2.2. Zone correction Plates


2.3 Semicircular Apertures


2.4. Dark Field Methods

References (Section 2)


3. Prospects of High Resolution Microscopy Using Phase Plates


3.1. General aspects


3.2. Preparation of Phase Plates


3.3. The Self-Scattering of Phase Plates


3.4. Interferometry with the Electron Microscope

References (Section 3)


4. Spatial Filtering in Optical Reconstruction of High Resolution Phase Contrast Images


4.1. Introduction


4.2. Theoretical Considerations


4.3. Arrangements


4.4. Experiments


4.5. Zonal filtering

References (Section 4)

A. C. van Dorsten: Contrast Phenomena in Electron Images of Amorphous and Macromolecular Objects


1.


1.1. Introduction


1.2. Information Theoretical Aspects


1.3. Speed of Picture Reading


1.4. Statistical Effects


1.5. Extended-area Contrast


2.


2.1. Small-Area Contrast


2.2. Structure of the Wave Field Immediately Behind the Object


2.3. Special Case of Pure Phase Modulation


2.4. The Occurrence of Amplitude Modulation in the Real Object Function


2.5. Appearance of Phase Structure


2.6. Objects Exceeding in Thickness the Fresnel Length /2λ0


2.7. Defocusing effects


3.


3.1. Contrast Enhancing Procedures by Means of Specimen Treatment And image conversion and image processing


3.2. Staining


3.3. Anomalous Contrast


3.4. Shadow Casting


3.5. Atomic Injection


3.6. Choice of Electron Optical Parameters


3.7. Image Conversion

References

C. R. Hall: Contrast Calculations for Small Clusters of Atoms


1. Introduction


2. Outline of the Method of Calculation


3. Results of calculations


3.1. Single Atom Images


3.2. Pairs of Atoms


3.3. Larger Clusters of Atoms


3.4. Effect of Astigmatism


4. Conclusions

Acknowledgements

References

R. H. Wade: Some Aspects of Lorentz Microscopy


1. Introduction to Lorentz Microscopy


1.1. Image Contrast in Phase Microscopy


1.2. Abbe Theory of Image Formation


1.3. Magnetic Object as a Phase Object for Electrons


2. The Validity of Geometrical Optics


2.1. The Relationship Between Wave and Geometrical Optics


2.2. Reduced Parameters in the Wave and Geometrical Optics Equations


2.3. The Application of Wohlleben's Criterion


2.4. The Generalised Criterion


2.5. Another Formulation of the Generalised Criterion


2.6. Application to Periodic Objects


3. Experimental investigations of Magnetic Structure


3.1. The Domain Wall


3.2. The Ripple Problem

References

D. Wohlleben: Magnetic Phase Contrast


1. Introduction


2. Electron Wave Function in the Presence of a Thin Magnetic Object


3. Wave Optical vs. Geometric Lorentz Contrast


4. Practical Manifestations of Diffraction Effects in Lorentz Microscopy


4.1. Domain Walls in the Defocused Mode


4.2. Domain Walls in Foucault Mode


5. Phase shift, Scattering Probability and Pignal to Poise Ratio


5.1. Example


6. Signal to Noise Ratio and Maximum Contrast


6.1. Strong Inhomogeneity


6.2. Weak Inhomogeneity


7. Number Phase Uncertainty Relation in Phase-Contrast Microscopy


7.1. Optimal Resolution of a Domain Wall


8. Separation of Magnetic and Electric Contrast


8.1. Separation at High Energy


8.2. Separation by the Parity Operation

References