Scanning Electron Microscopy and X-Ray Microanalysis

In the last decade, since the publication of the first edition of Scanning Electron Microscopy and X-ray Microanalysis, there has been a great expansion in the capabilities of the basic SEM and EPMA. High­ resolution imaging has been developed with the aid of an extensive range of field emission gun (FEG) microscopes. The magnification ranges of these instruments now overlap those of the transmission electron microscope. Low-voltage microscopy using the FEG now allows for the observation of noncoated samples. In addition, advances in the develop­ ment of x-ray wavelength and energy dispersive spectrometers allow for the measurement of low-energy x-rays, particularly from the light elements (B, C, N, 0). In the area of x-ray microanalysis, great advances have been made, particularly with the "phi rho z" [Ij)(pz)] technique for solid samples, and with other quantitation methods for thin films, particles, rough surfaces, and the light elements. In addition, x-ray imaging has advanced from the conventional technique of "dot mapping" to the method of quantitative compositional imaging. Beyond this, new software has allowed the development of much more meaningful displays for both imaging and quantitative analysis results and the capability for integrating the data to obtain specific information such as precipitate size, chemical analysis in designated areas or along specific directions, and local chemical inhomogeneities.

1. Introduction.- 1.1. Evolution of the Scanning Electron Microscope.- 1.2. Evolution of the Electron Probe Microanalyzer.- 1.3. Outline of This Book.- 2. Electron Optics.- 2.1. How the SEM Works.- 2.2. Electron Guns.- 2.3. Electron Lenses.- 2.4. Electron Probe Diameter versus Electron Probe Current.- 2.5. Summary of SEM Microscopy Modes.- 3. Electron-Specimen Interactions.- 3.1. Introduction.- 3.2. Electron Scattering.- 3.3. Interaction Volume.- 3.4. Signals from Elastic Scattering.- 3.5. Signals from Inelastic Scattering.- 3.6. Summary.- 4. Image Formation and Interpretation.- 4.1. Introduction.- 4.2. The Basic SEM Imaging Process.- 4.3. Detectors.- 4.4. Image Contrast at Low Magnification (100,000x).- 4.7. Image Processing for the Display of Contrast Information.- 4.8. Defects of the SEM Imaging Process.- 4.9. Special Topics in SEM Imaging.- 4.10. Developing a Comprehensive Imaging Strategy.- 5. X-Ray Spectral Measurement: WDS and EDS.- 5.1. Introduction.- 5.2. Wavelength-Dispersive Spectrometer.- 5.3. Energy-Dispersive X-Ray Spectrometer.- 5.4. Comparison of WDS and EDS.- Appendix: Initial Detector Setup and Testing.- 6. Qualitative X-Ray Analysis.- 6.1. Introduction.- 6.2. EDS Qualitative Analysis.- 6.3. WDS Qualitative Analysis.- 6.4. Automatic Qualitative EDS Analysis.- 7. X-Ray Peak and Background Measurements.- 7.1. General Considerations for X-Ray Data Handling.- 7.2. Background Correction.- 7.3. Peak Overlap Correction.- 8. Quantitative X-Ray Analysis: The Basics.- 8.1. Introduction.- 8.2. Advantages of Quantitative X-Ray Microanalysis in the SEM/EPMA.- 8.3. Quantitative Analysis Procedures.- 8.4. The Approach to X-Ray Quantitation: The Need for Matrix Corrections.- 8.5. The Physical Origin of Matrix Effects.- 8.6. X-Ray Production.- 8.7. ZAF Factors in Microanalysis.- 8.8. Types of Matrix Correction Schemes.- 8.9. Caveats.- 9. Quantitative X-Ray Analysis: Theory and Practice.- 9.1. Introduction.- 9.2. ZAF Technique.- 9.3. ø; (?z) Technique.- 9.8. Special Sample Analysis.- 9.9. Precision and Sensitivity in X-Ray Analysis.- 9.10. Light-Element Analysis.- Appendix 9.1. Equations for the ?, ?, ?, and ø(0) Terms of the Packwood-Brown ø (?z) Equation.- Appendix 9.2. Solutions for the Atomic Number and Absorption Corrections.- 10. Compositional Imaging.- 10.1. Introduction.- 10.2. Analog X-Ray Area Scanning (Dot Mapping).- 10.3. Digital Compositional Mapping..- 11. Specimen Preparation for Inorganic Materials: Microstructural and Microchemical Analysis.- 11.1. Metals.- 11.2. Ceramics and Geological Specimens.- 11.3. Electronic Devices and Packages.- 11.4. Semiconductors.- 11.5. Sands, Soils, and Clays.- 11.6. Particles and Fibers.- 12. Sample Preparation for Biological, Organic, Polymeric, and Hydrated Materials.- 12.1. Introduction.- 12.2. Compromising the Electron-Beam Instrument.- 12.3. Compromising the Sample.- 12.4. Correlative Microscopy.- 12.5. Techniques for Structural Studies.- 12.6. Specimen Preparation for Localization of Metabolic Activity and Chemical Specificity.- 12.7 Preparative Procedures for Organic Samples Such as Polymers, Plastics, and Paints.- 12.8. Low-Temperature Specimen Preparation for Structural and Analytical Studies.- 12.9. Damage, Artifact, and Interpretation.- 12.10. Specific Preparative Procedures: A Bibliography.- 13. Coating and Conductivity Techniques for SEM and Microanalysis.- 13.1. Introduction.- 13.2. Specimen Characteristics.- 13.3. Untreated Specimens.- 13.4.Bulk Conductivity Staining Methods.- 13.5. Specimen Mounting Procedures.- 13.6. Thin-Film Methods.- 13.7. Thermal Evaporation.- 13.8. Sputter Coating.- 13.9. Specialized Coating Methods.- 13.10. Determination of Coating Thickness.- 13.11. Artifacts Related to Coating and Bulk-Conductivity Procedures.- 13.12. Conclusions.- 14 Data Base.- Table 14.1. Atomic Number, Atomic Weight, and Density of Elements.- Table 14.2. Common Oxides of the Elements.- Table 14.3. Mass Absorption Coefficients for ? Lines.- Table 14.4. Mass Absorption Coefficients for ? Lines.- Table 14.5. Mass Absorption Coefficients for ? Lines.- Table 14.6. K Series X-Ray Wavelengths and Energies.- Table 14.7. L Series X-Ray Wavelengths and Energies !.- Table 14.8. M Series X-Ray Wavelengths and Energies.- Table 14.9. J and Fluorescent Yield (?) by Atomic Number.- Table 14.10. Important Properties of Selected Coating Elements.- References.