9780306472923

Introduction

(20)

Imaging Capabilities

(8)

Structure Analysis

(1)

Elemental Analysis

(7)

Summary and Outline of This Book

(4)

Appendix A. Overview of Scanning Electron Microscopy

(1)

Appendix B. Overview of Electron Probe X-Ray Microanalysis

(1)

References

(1)

The SEM and Its Modes of Operation

(40)

How the SEM Works

(8)

Functions of the SEM Subsystems

(1)

Electron Gun and Lenses Produce a Small Electron Beam

(1)

Deflection System Controls Magnification

(2)

Electron Detector Collects the Signal

(1)

Camera or Computer Records the Image

(1)

Operator Controls

(1)

SEM Imaging Modes

(2)

Resolution Mode

(1)

High-Current Mode

(1)

Depth-of-Focus Mode

(1)

Low-Voltage Mode

(1)

Why Learn about Electron Optics?

(1)

Electron Guns

(11)

Tungsten Hairpin Electron Guns

(1)

Filament

(1)

Grid Cap

(1)

Anode

(1)

Emission Current and Beam Current

(1)

Operator Control of the Electron Gun

(1)

Electron Gun Characteristics

(1)

Electron Emission Current

(1)

Brightness

(1)

Lifetime

(1)

Source Size, Energy Spread, Beam Stability

(1)

Improved Electron Gun Characteristics

(1)

Lanthanum Hexaboride (LaB6) Electron Guns

(1)

Introduction

(1)

Operation of the LaB6 Source

(1)

Field Emission Electron Guns

(3)

Electron Lenses

(14)

Making the Beam Smaller

(1)

Electron Focusing

(1)

Demagnification of the Beam

(1)

Lenses in SEMs

(1)

Condenser Lenses

(1)

Objective Lenses

(2)

Real and Virtual Objective Apertures

(1)

Operator Control of SEM Lenses

(1)

Effect of Aperture Size

(1)

Effect of Working Distance

(1)

Effect of Condenser Lens Strength

(1)

Gaussian Probe Diameter

(1)

Lens Aberrations

(1)

Spherical Aberration

(1)

Aperture Diffraction

(1)

Chromatic Aberration

(1)

Astigmatism

(2)

Aberrations in the Objective Lens

(1)

Electron Probe Diameter versus Electron Probe Current

(7)

Calculation of dmin and imax

(1)

Minimum Probe Size

(1)

Minimum Probe Size at 10--30 kV

(1)

Maximum Probe Current at 10--30 kV

(1)

Low-Voltage Operation

(1)

Graphical Summary

(1)

Performance in the SEM Modes

(1)

Resolution Mode

(2)

High-Current Mode

(1)

Depth-of-Focus Mode

(1)

Low-Voltage SEM

(1)

Environmental Barriers to High-Resolution Imaging

(1)

References

(1)

Electron Beam-Specimen Interactions

(38)

The Story So Far

(1)

The Beam Enters the Specimen

(4)

The Interaction Volume

(10)

Visualizing the Interaction Volume

(2)

Simulating the Interaction Volume

(1)

Influence of Beam and Specimen Parameters on the Interaction Volume

(1)

Influence of Beam Energy on the Interaction Volume

(1)

Influence of Atomic Number on the Interaction Volume

(2)

Influence of Specimen Surface Tilt on the Interaction Volume

(1)

Electron Range: A Simple Measure of the Interaction Volume

(1)

Introduction

(1)

The Electron Range at Low Beam Energy

(2)

Imaging Signals from the Interaction Volume

(24)

Backscattered Electrons

(1)

Atomic Number Dependence of BSE

(2)

Beam Energy Dependence of BSE

(2)

Tilt Dependence of BSE

(1)

Angular Distribution of BSE

(2)

Energy Distribution of BSE

(2)

Lateral Spatial Distribution of BSE

(2)

Sampling Depth of BSE

(2)

Secondary Electrons

(1)

Definition and Origin of SE

(1)

SE Yield with Primary Beam Energy

(2)

SE Energy Distribution

(1)

Range and Escape Depth of SE

(2)

Relative Contributions of SE1 and SE2

(2)

Specimen Composition Dependence of SE

(1)

Specimen Tilt Dependence of SE

(1)

Angular Distribution of SE

(1)

References

(2)

Image Formation and Interpretation

(96)

The Story So Far

(1)

The Basic SEM Imaging Process

(26)

Scanning Action

101

(2)

Image Construction (Mapping)

103

(1)

Line Scans

103

(1)

Image (Area) Scanning

104

(3)

Digital Imaging: Collection and Display

107

(1)

Magnification

108

(2)

Picture Element (Pixel) Size

110

(4)

Low-Magnification Operation

114

(1)

Depth of Field (Focus)

114

(4)

Image Distortion

118

(1)

Projection Distortion: Gnomonic Projection

118

(1)

Projection Distortion: Image Foreshortening

119

(4)

Scan Distortion: Pathological Defects

123

(2)

Moire Effects

125

(1)

Detectors

125

(14)

Introduction

125

(2)

Electron Detectors

127

(1)

Everhart--Thornley Detector

128

(4)

``Through-the-Lens'' (TTL) Detector

132

(1)

Dedicated Backscattered Electron Detectors

133

(6)

The Roles of the Specimen and Detector in Contrast Formation

139

(34)

Contrast

139

(2)

Compositional (Atomic Number) Contrast

141

(1)

Introduction

141

(1)

Compositional Contrast with Backscattered Electrons

141

(4)

Topographic Contrast

145

(1)

Origins of Topographic Contrast

146

(1)

Topographic Contrast with the Everhart--Thornley Detector

147

(4)

Light-Optical Analogy

151

(7)

Interpreting Topographic Contrast with Other Detectors

158

(15)

Image Quality

173

(5)

Image Processing for the Display of Contrast Information

178

(17)

The Signal Chain

178

(2)

The Visibility Problem

180

(2)

Analog and Digital Image Processing

182

(2)

Basic Digital Image Processing

184

(3)

Digital Image Enhancement

187

(5)

Digital Image Measurements

192

(1)

References

192

(3)

Special Topics in Scanning Electron Microscopy

195

(76)

High-Resolution Imaging

195

(8)

The Resolution Problem

195

(2)

Achieving High Resolution at High Beam Energy

197

(4)

High-Resolution Imaging at Low Voltage

201

(2)

STEM-in-SEM: High Resolution for the Special Case of Thin Specimens

203

(4)

Surface Imaging at Low Voltage

207

(2)

Making Dimensional Measurements in the SEM

209

(3)

Recovering the Third Dimension: Stereomicroscopy

212

(8)

Qualitative Stereo Imaging and Presentation

212

(5)

Quantitative Stereo Microscopy

217

(3)

Variable-Pressure and Environmental SEM

220

(22)

Current Instruments

221

(1)

Gas in the Specimen Chamber

222

(1)

Units of Gas Pressure

222

(1)

The Vacuum System

222

(3)

Electron Interactions with Gases

225

(6)

The Effect of the Gas on Charging

231

(5)

Imaging in the ESEM and the VPSEM

236

(5)

X-Ray Microanalysis in the Presence of a Gas

241

(1)

Special Contrast Mechanisms

242

(14)

Electric Fields

243

(2)

Magnetic Fields

245

(1)

Type 1 Magnetic Contrast

245

(2)

Type 2 Magnetic Contrast

247

(1)

Crystallographic Contrast

247

(9)

Electron Backscatter Patterns

256

(15)

Origin of EBSD Patterns

260

(2)

Hardware for EBSD

262

(2)

Resolution of EBSD

264

(1)

Lateral Spatial Resolution

264

(2)

Depth Resolution

266

(1)

Applications

267

(1)

Orientation Mapping

267

(1)

Phase Identification

267

(2)

References

269

(2)

Generation of X-Rays in the SEM Specimen

271

(26)

Continuum X-Ray Production (Bremsstrahlung)

271

(3)

Characteristic X-Ray Production

274

(12)

Origin

274

(1)

Fluorescence Yield

275

(1)

Electron Shells

276

(1)

Energy-Level Diagram

277

(1)

Electron Transitions

277

(1)

Critical Ionization Energy

278

(1)

Moseley's Law

279

(1)

Families of Characteristic Lines

279

(2)

Natural Width of Characteristic X-Ray Lines

281

(1)

Weights of Lines

282

(1)

Cross Section for Inner Shell Ionization

283

(1)

X-Ray Production in Thin Foils

284

(1)

X-Ray Production in Thick Targets

284

(1)

X-Ray Peak-to-Background Ratio

285

(1)

Depth of X-Ray Production (X-Ray Range)

286

(3)

Anderson--Hasler X-Ray Range

286

(1)

X-Ray Spatial Resolution

286

(2)

Sampling Volume and Specimen Homogeneity

288

(1)

Depth Distribution of X-Ray Production, φ(pz)

288

(1)

X-Ray Absorption

289

(3)

Mass Absorption Coefficient for an Element

290

(1)

Effect of Absorption Edge on Spectrum

291

(1)

Absorption Coefficient for Mixed-Element Absorbers

291

(1)

X-Ray Fluorescence

292

(5)

Characteristic Fluorescence

293

(1)

Continuum Fluorescence

294

(1)

Range of Fluorescence Radiation

295

(1)

References

295

(2)

X-Ray Spectral Measurement: EDS and WDS

297

(58)

Introduction

297

(1)

Energy-Dispersive X-Ray Spectrometer

297

(26)

Operating Principles

297

(4)

The Detection Process

301

(1)

Charge-to-Voltage Conversion

302

(1)

Pulse-Shaping Linear Amplifier and Pileup Rejection Circuitry

303

(5)

The Computer X-Ray Analyzer

308

(3)

Digital Pulse Processing

311

(1)

Spectral Modification Resulting from the Detection Process

312

(1)

Peak Broadening

312

(4)

Peak Distortion

316

(1)

Silicon X-Ray Escape Peaks

317

(1)

Absorption Edges

318

(2)

Silicon Internal Fluorescence Peak

320

(1)

Artifacts from the Detector Environment

321

(1)

Summary of EDS Operation and Artifacts

322

(1)

Wavelength-Dispersive Spectrometer

323

(17)

Introduction

323

(1)

Basic Description

324

(1)

Diffraction Conditions

325

(2)

Diffracting Crystals

327

(3)

The X-Ray Proportional Counter

330

(3)

Detector Electronics

333

(7)

Comparison of Wavelength-Dispersive Spectrometers with Conventional Energy-Dispersive Spectrometers

340

(7)

Geometric Collection Efficiency

340

(1)

Quantum Efficiency

341

(1)

Resolution

342

(2)

Spectral Acceptance Range

344

(1)

Maximum Count Rate

344

(1)

Minimum Probe Size

344

(2)

Speed of Analysis

346

(1)

Spectral Artifacts

346

(1)

Emerging Detector Technologies

347

(8)

X-Ray Microcalorimetery

347

(2)

Silicon Drift Detectors

349

(1)

Parallel Optic Diffraction-Based Spectrometers

350

(3)

References

353

(2)

Qualitative X-Ray Analysis

355

(36)

Introduction

355

(2)

EDS Qualitative Analysis

357

(25)

X-Ray Peaks

357

(9)

Guidelines for EDS Qualitative Analysis

366

(2)

General Guidelines for EDS Qualitative Analysis

368

(4)

Examples of Manual EDS Qualitative Analysis

372

(2)

Pathological Overlaps in EDS Qualitative Analysis

374

(5)

Advanced Qualitative Analysis: Peak Stripping

379

(2)

Automatic Qualitative EDS Analysis

381

(1)

WDS Qualitative Analysis

382

(9)

Wavelength-Dispersive Spectrometry of X-Ray Peaks

382

(6)

Guidelines for WDS Qualitative Analysis

388

(2)

References

390

(1)

Quantitative X-Ray Analysis: The Basics

391

(62)

Introduction

391

(1)

Advantages of Conventional Quantitative X-Ray Microanalysis in the SEM

392

(1)

Quantitative Analysis Procedures: Flat-Polished Samples

393

(9)

The Approach to X-Ray Quantitation: The Need for Matrix Corrections

402

(1)

The Physical Origin of Matrix Effects

403

(1)

ZAF Factors in Microanalysis

404

(12)

Atomic number effect, Z

404

(1)

Effect of Backscattering (R) and Energy Loss (S)

404

(2)

X-Ray Generation with Depth, φ(pz)

406

(5)

X-Ray Absorption Effect, A

411

(4)

X-Ray Fluorescence, F

415

(1)

Calculation of ZAF Factors

416

(5)

Atomic Number Effect, Z

417

(1)

Absorption correction, A

417

(1)

Characteristic Fluorescence Correction, F

418

(1)

Calculation of ZAF

418

(2)

The Analytical Total

420

(1)

Practical Analysis

421

(32)

Examples of Quantitative Analysis

421

(1)

Al-Cu Alloys

421

(2)

Ni--10 wt% Fe Alloy

423

(1)

Ni--38.5 wt% Cr-3.0 wt% Al Alloy

423

(2)

Pyroxene: 53.5 wt% SiO2, 1.11 wt% Al2O3, 0.62 wt% Cr2O3, 9.5 wt% FeO, 14.1 wt% MgO, and 21.2 wt% CaO

425

(2)

Standardless Analysis

427

(2)

First-Principles Standardless Analysis

429

(4)

``Fitted-Standards'' Standardless Analysis

433

(3)

Special Procedures for Geological Analysis

436

(1)

Introduction

436

(1)

Formulation of the Bence--Albee Procedure

437

(1)

Application of the Bence--Albee Procedure

438

(1)

Specimen Conductivity

439

(1)

Precision and Sensitivity in X-Ray Analysis

440

(1)

Statistical Basis for Calculating Precision and Sensitivity

440

(2)

Precision of Composition

442

(2)

Sample Homogeneity

444

(1)

Analytical Sensitivity

445

(1)

Trace Element Analysis

446

(2)

Trace Element Analysis Geochronologic Applications

448

(1)

Biological and Organic Specimens

449

(1)

References

449

(4)

Special Topics in Electron Beam X-Ray Microanalysis

453

(84)

Introduction

453

(1)

Thin Film on a Substrate

454

(8)

Particle Analysis

462

(14)

Particle Mass Effect

463

(1)

Particle Absorption Effect

463

(1)

Particle Fluorescence Effect

464

(1)

Particle Geometric Effects

465

(1)

Corrections for Particle Geometric Effects

466

(1)

The Consequences of Ignoring Particle Effects

466

(1)

Normalization

466

(2)

Critical Measurement Issues for Particles

468

(2)

Advanced Quantitative Methods for Particles

470

(6)

Rough Surfaces

476

(4)

Introduction

476

(3)

Rough Specimen Analysis Strategy

479

(1)

Reorientation

479

(1)

Normalization

479

(1)

Peak-to-Background Method

479

(1)

Beam-Sensitive Specimens (Biological, Polymeric)

480

(5)

Thin-Section Analysis

480

(3)

Bulk Biological and Organic Specimens

483

(2)

X-Ray Mapping

485

(14)

Relative Merits of WDS and EDS for Mapping

486

(1)

Digital Dot Mapping

487

(1)

Gray-Scale Mapping

488

(1)

The Need for Scaling in Gray-Scale Mapping

489

(2)

Artifacts in X-Ray Mapping

491

(1)

Compositional Mapping

492

(1)

Principles of Compositional Mapping

492

(2)

Advanced Spectrum Collection Strategies for Compositional Mapping

494

(3)

The Use of Color in Analyzing and Presenting X-Ray Maps

497

(1)

Primary Color Superposition

497

(1)

Pseudocolor Scales

497

(2)

Light Element Analysis

499

(19)

Optimization of Light Element X-Ray Generation

499

(4)

X-Ray Spectrometry of the Light Elements

503

(1)

Si EDS

503

(4)

WDS

507

(4)

Special Measurement Problems for the Light Elements

511

(1)

Contamination

511

(1)

Overvoltage Effects

512

(2)

Absorption Effects

514

(1)

Light Element Quantification

515

(3)

Low-Voltage Microanalysis

518

(13)

``Low-Voltage'' versus ``Conventional'' Microanalysis

518

(1)

X-Ray Production Range

519

(1)

Contribution of the Beam Size to the X-Ray Analytical Resolution

520

(3)

A Consequence of the X-Ray Range under Low-Voltage Conditions

523

(2)

X-Ray Spectrometry in Low-Voltage Microanalysis

525

(1)

The Oxygen and Carbon Problem

526

(2)

Quantitative X-Ray Microanalysis at Low Voltage

528

(3)

Report of Analysis

531

(6)

References

535

(2)

Specimen Preparation of Hard Materials: Metals, Ceramics, Rocks, Minerals, Microelectronic and Packaged Devices, Particles, and Fibers

537

(28)

Metals

537

(4)

Specimen Preparation for Surface Topography

537

(1)

Specimen Preparation for Microstructural and Microchemical Analysis

538

(1)

Initial Sample Selection and Specimen Preparation Steps

538

(1)

Final Polishing Steps

539

(1)

Preparation for Microanalysis

540

(1)

Ceramics and Geological Samples

541

(2)

Initial Specimen Preparation: Topography and Microstructure

542

(1)

Mounting and Polishing for Microstructural and Microchemical Analysis

542

(1)

Final Specimen Preparation for Microstructural and Microchemical Analysis

542

(1)

Microelectronics and Packages

543

(2)

Initial Specimen Preparation

543

(1)

Polishing

544

(1)

Final Preparation

545

(1)

Imaging of Semiconductors

545

(2)

Voltage Contrast

546

(1)

Charge Collection

546

(1)

Preparation for Electron Diffraction in the SEM

547

(4)

Channeling Patterns and Channeling Contrast

547

(1)

Electron Backscatter Diffraction

547

(4)

Special Techniques

551

(6)

Plasma Cleaning

551

(2)

Focused-Ion-Beam Sample Preparation for SEM

553

(1)

Application of FIB for Semiconductors

554

(1)

Applications of FIB in Materials Science

555

(2)

Particles and Fibers

557

(8)

Particle Substrates and Supports

559

(1)

Bulk Particle Substrates

559

(1)

Thin Particle Supports

560

(1)

Particle Mounting Techniques

560

(2)

Particles Collected on Filters

562

(1)

Particles in a Solid Matrix

563

(1)

Transfer of Individual Particles

563

(1)

References

564

(1)

Specimen Preparation of Polymer Materials

565

(26)

Introduction

565

(1)

Microscopy of Polymers

565

(5)

Radiation Effects

566

(1)

Imaging Compromises

567

(1)

Metal Coating Polymers for Imaging

567

(3)

X-Ray Microanalysis of Polymers

570

(1)

Specimen Preparation Methods for Polymers

570

(11)

Simple Preparation Methods

571

(1)

Polishing of Polymers

571

(1)

Microtomy of Polymers

572

(1)

Fracture of Polymer Materials

573

(3)

Staining of Polymers

576

(2)

Osmium Tetroxide and Ruthenium Tetroxide

578

(1)

Ebonite

578

(1)

Chlorosulfonic Acid and Phosphotungstic Acid

578

(1)

Etching of Polymers

579

(1)

Replication of Polymers

580

(1)

Rapid Cooling and Drying Methods for Polymers

580

(1)

Simple Cooling Methods

580

(1)

Freeze-Drying

581

(1)

Critical-Point Drying

581

(1)

Choosing Specimen Preparation Methods

581

(7)

Fibers

582

(1)

Films and Membranes

582

(1)

Engineering Resins and Plastics

583

(4)

Emulsions and Adhesives

587

(1)

Problem-Solving Protocol

588

(1)

Image Interpretation and Artifacts

589

(2)

References

590

(1)

Ambient-Temperature Specimen Preparation of Biological Material

591

(30)

Introduction

591

(1)

Preparative Procedures for the Structural SEM of Single Cells, Biological Particles, and Fibers

592

(4)

Particulate, Cellular, and Fibrous Organic Material

592

(1)

Dry Organic Particles and Fibers

593

(1)

Organic Particles and Fibers on a Filter

594

(1)

Organic Particles and Fibers Entrained within a Filter

594

(1)

Organic Particulate Matter Suspended in a Liquid

594

(1)

Manipulating Individual Organic Particles

595

(1)

Preparative Procedures for the Structural Observation of Large Soft Biological Specimens

596

(11)

Introduction

596

(1)

Sample Handling before Fixation

596

(1)

Fixation

596

(1)

Microwave Fixation

597

(1)

Conductive Infiltration

597

(1)

Dehydration

597

(5)

Embedding

602

(1)

Exposing the Internal Contents of Bulk Specimens

602

(1)

Mechanical Dissection

602

(1)

High-Energy-Beam Surface Erosion

602

(1)

Chemical Dissection

603

(1)

Surface Replicas and Corrosion Casts

604

(1)

Specimen Supports and Methods of Sample Attachment

605

(2)

Artifacts

607

(1)

Preparative Procedures for the in Situ Chemical Analysis of Biological Specimens in the SEM

607

(14)

Introduction

607

(1)

Preparative Procedures for Elemental Analysis Using X-Ray Microanalysis

608

(1)

The Nature and Extent of the Problem

608

(1)

Types of Sample That May be Analyzed

609

(1)

The General Strategy for Sample Preparation

609

(1)

Criteria for Judging Satisfactory Sample Preparation

610

(1)

Fixation and Stabilization

610

(1)

Precipitation Techniques

611

(1)

Procedures for Sample Dehydration, Embedding, and Staining

611

(1)

Specimen Supports

611

(1)

Preparative Procedures for Localizing Molecules Using Histochemistry

612

(1)

Staining and Histochemical Methods

612

(1)

Atomic Number Contrast with Backscattered Electrons

613

(1)

Preparative Procedures for Localizing Macromolecues Using Immunocytochemistry

614

(1)

Introduction

614

(1)

The Antibody--Antigen Reaction

614

(1)

General Features of Specimen Preparation for Immunocytochemistry

615

(1)

Imaging Procedures in the SEM

616

(2)

References

618

(3)

Low-Temperature Specimen Preparation

621

(26)

Introduction

621

(1)

The Properties of Liquid Water and Ice

622

(1)

Conversion of Liquid Water to Ice

623

(1)

Specimen Pretreatment before Rapid (Quench) Cooling

624

(3)

Minimizing Sample Size and Specimen Holders

624

(2)

Maximizing Undercooling

626

(1)

Altering the Nucleation Process

626

(1)

Artificially Depressing the Sample Freezing Point

626

(1)

Chemical Fixation

626

(1)

Quench Cooling

627

(4)

Liquid Cryogens

627

(1)

Solid Cryogens

628

(1)

Methods for Quench Cooling

629

(1)

Comparison of Quench Cooling Rates

630

(1)

Low-Temperature Storage and Sample Transfer

631

(1)

Manipulation of Frozen Specimens: Cryosectioning, Cryofracturing, and Cryoplaning

631

(4)

Cryosectioning

631

(2)

Cryofracturing

633

(1)

Cryopolishing or Cryoplaning

634

(1)

Ways to Handle Frozen Liquids within the Specimen

635

(5)

Frozen-Hydrated and Frozen Samples

636

(1)

Freeze-Drying

637

(1)

Physical Principles Involved in Freeze-Drying

637

(1)

Equipment Needed for Freeze-Drying

638

(1)

Artifacts Associated with Freeze-Drying

639

(1)

Freeze Substitution and Low-Temperature Embedding

639

(1)

Physical Principles Involved in Freeze Substitution and Low-Temperature Embedding

639

(1)

Equipment Needed for Freeze Substitution and Low-Temperature Embedding

640

(1)

Procedures for Hydrated Organic Systems

640

(1)

Procedures for Hydrated Inorganic Systems

641

(1)

Procedures for Nonaqueous Liquids

642

(1)

Imaging and Analyzing Samples at Low Temperatures

643

(4)

References

644

(3)

Procedures for Elimination of Charging in Nonconducting Specimens

647

(28)

Introduction

647

(3)

Recognizing Charging Phenomena

650

(6)

Procedures for Overcoming the Problems of Charging

656

(1)

Vacuum Evaporation Coating

657

(4)

High-Vacuum Evaporation Methods

658

(3)

Low-Vacuum Evaporation Methods

661

(1)

Sputter Coating

661

(6)

Plasma Magnetron Sputter Coating

662

(2)

Ion Beam and Penning Sputtering

664

(3)

High-Resolution Coating Methods

667

(2)

Coating for Analytical Studies

669

(1)

Coating Procedures for Samples Maintained at Low Temperatures

669

(1)

Coating Thickness

670

(2)

Damage and Artifacts on Coated Samples

672

(1)

Summary of Coating Guidelines

673

(2)

References

673

(2)

Index

675

Enhancements CD

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Scanning Electron Microscopy and X-Ray Microanalysis

0306472929

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