Scanning electron microscopy and x-ray microanalysis [Fourth edition] 9781493966745, 9781493966769, 2017943045, 149396674X, 1493966766

Table of contents :
Preface......Page 5
Imaging Microscopic Features......Page 7
Measuring the Elemental Composition......Page 10
Dual-Beam Platforms: Combined Electron and Ion Beams......Page 13
References......Page 14
Contents......Page 15
1: Electron Beam—Specimen Interactions: Interaction Volume......Page 24
1.2 Inelastic Scattering (Energy Loss) Limits Beam Electron Travel in the Specimen......Page 25
1.3.1 How Frequently Does Elastic Scattering Occur?......Page 27
1.4 Simulating the Effects of Elastic Scattering: Monte Carlo Calculations......Page 28
1.4.2 Monte Carlo Simulation To Visualize the Electron Interaction Volume......Page 29
How Does the Interaction Volume Change with Specimen Tilt?......Page 31
1.5 A Range Equation To Estimate the Size of the Interaction Volume......Page 35
References......Page 37
2: Backscattered Electrons......Page 38
2.2.1 BSE Response to Specimen Composition (η vs. Atomic Number, Z)......Page 39
SEM Image Contrast with BSE: “Atomic Number Contrast”......Page 41
2.2.2 BSE Response to Specimen Inclination (η vs. Surface Tilt, θ)......Page 43
SEM Image Contrast: “BSE Topographic Contrast—Number Effects”......Page 44
Beam Incident at an Acute Angle to the Specimen Surface (Specimen Tilt > 0°)......Page 45
Depth Distribution of Backscattering......Page 46
Radial Distribution of Backscattered Electrons......Page 48
2.3 Summary......Page 50
References......Page 51
3: Secondary Electrons......Page 52
3.4 Secondary Electron Yield Versus Atomic Number......Page 53
3.6 Angular Distribution of  Secondary Electrons......Page 57
3.8 Spatial Characteristics of Secondary Electrons......Page 58
References......Page 60
4: X-Rays......Page 61
4.2.1 Origin......Page 62
4.2.2 Fluorescence Yield......Page 63
4.2.3 X-Ray Families......Page 64
4.2.4 X-Ray Nomenclature......Page 65
X-Ray Production in Thin Foils......Page 66
4.3 X-Ray Continuum (bremsstrahlung)......Page 69
4.3.2 The Electron-Excited X-Ray Spectrum, As-Generated......Page 71
4.3.3 Range of X-ray Production......Page 72
4.3.4 Monte Carlo Simulation of X-Ray Generation......Page 73
4.3.5 X-ray Depth Distribution Function, ϕ(ρz)......Page 75
4.4 X-Ray Absorption......Page 76
4.5 X-Ray Fluorescence......Page 81
References......Page 85
5: Scanning Electron Microscope (SEM) Instrumentation......Page 86
5.2.1 Beam Energy......Page 87
5.2.3 Beam Current......Page 88
5.2.5 Beam Convergence Angle, α......Page 89
5.2.6 Beam Solid Angle......Page 90
5.2.7 Electron Optical Brightness, β......Page 91
5.2.8 Focus......Page 92
Astigmatism......Page 93
5.3.1 High Depth-of-Field Mode......Page 96
5.3.2 High-Current Mode......Page 99
5.3.3 Resolution Mode......Page 101
5.3.4 Low-Voltage Mode......Page 102
Angular Measures for Electron Detectors......Page 104
Solid Angle, Ω......Page 105
Scintillation Detectors......Page 106
Everhart–Thornley Detector......Page 107
5.4.5 Specimen Current: The Specimen as Its Own Detector......Page 109
Measuring the DQE: BSE Semiconductor Detector......Page 110
References......Page 112
6: Image Formation......Page 113
6.1 Image Construction by Scanning Action......Page 114
6.3.1 Calibrating the Image......Page 115
Using a Calibrated Structure in ImageJ-Fiji......Page 117
6.4.1 Projection Distortion (Foreshortening)......Page 118
6.4.2 Image Defocusing (Blurring)......Page 120
6.5 Making Measurements on Surfaces With Arbitrary Topography: Stereomicroscopy......Page 122
6.5.1 Qualitative Stereomicroscopy......Page 123
Fixed beam, Specimen Position Altered......Page 124
Fixed Specimen, Beam Incidence Angle Changed......Page 126
6.5.2 Quantitative Stereomicroscopy......Page 127
Measuring a Simple Vertical Displacement......Page 128
References......Page 130
7: SEM Image Interpretation......Page 131
7.2.1 Atomic Number Contrast With Backscattered Electrons......Page 132
7.2.3 BSE Atomic Number Contrast With the Everhart–Thornley Detector......Page 133
7.3 Interpretation of SEM Images of Specimen Topography......Page 134
7.3.1 Imaging Specimen Topography With the Everhart–Thornley Detector......Page 135
7.3.2 The Light-Optical Analogy to the SEM/E–T (Positive Bias) Image......Page 136
Getting It Wrong: Breaking the Light-Optical Analogy of the Everhart–Thornley (Positive Bias) Detector......Page 137
SUM Mode (A + B)......Page 139
Examining Images Prepared With the Individual Detector Segments......Page 140
References......Page 141
8: The Visibility of Features in SEM Images......Page 142
8.1 Signal Quality: Threshold Contrast and Threshold Current......Page 143
References......Page 150
9: Image Defects......Page 151
9.1.1 What Is Specimen Charging?......Page 152
9.1.2 Recognizing Charging Phenomena in SEM Images......Page 153
Coating an Insulating Specimen for Charge Dissipation......Page 157
Choosing the Coating for Imaging Morphology......Page 159
9.2 Radiation Damage......Page 160
9.3 Contamination......Page 161
9.4 Moiré Effects: Imaging What Isn’t Actually There......Page 162
References......Page 164
10: High Resolution Imaging......Page 165
10.3 Pixel Size, Beam Footprint, and Delocalized Signals......Page 166
10.4 Secondary Electron Contrast at High Spatial Resolution......Page 168
10.4.1 SE Range Effects Produce Bright Edges (Isolated Edges)......Page 169
10.4.2 Even More Localized Signal: Edges Which Are Thin Relative to the Beam Range......Page 170
10.4.3 Too Much of a Good Thing: The Bright Edge Effect Can Hinder Distinguishing Shape......Page 171
10.4.4 Too Much of a Good Thing: The Bright Edge Effect Hinders Locating the True Position of an Edge for Critical Dimension Metrology......Page 172
Low Beam Energy Strategy......Page 174
High Beam Energy Strategy......Page 175
Making More SE1: Apply a Thin High-δ Metal Coating......Page 176
Making Fewer BSEs, SE2, and SE3 by Eliminating Bulk Scattering From the Substrate......Page 177
Scanning Transmission Electron Microscopy in the Scanning Electron Microscope (STEM-in-SEM)......Page 178
10.5.3 Eliminate the Use of SEs Altogether: “Low Loss BSEs“......Page 179
10.6.2 Pathological Specimen Behavior......Page 181
References......Page 182
11: Low Beam Energy SEM......Page 183
11.2 Secondary Electron and Backscattered Electron Signal Characteristics in the Low Beam Energy Range......Page 184
11.3.2 Low Beam Energy for High Depth Resolution SEM......Page 187
11.3.3 Extremely Low Beam Energy Imaging......Page 189
References......Page 190
12: Variable Pressure Scanning Electron Microscopy (VPSEM)......Page 191
12.2 How Does VPSEM Differ From the Conventional SEM Vacuum Environment?......Page 192
12.3.1 Control of Specimen Charging......Page 193
12.3.2 Controlling the Water Environment of a Specimen......Page 194
12.4 Gas Scattering Modification of the Focused Electron Beam......Page 195
12.5 VPSEM Image Resolution......Page 199
12.6.2 Secondary Electrons–Gas Amplification Detector......Page 200
12.7 Contrast in VPSEM......Page 202
References......Page 203
13: ImageJ and Fiji......Page 204
13.2 Fiji......Page 205
13.3 Plugins......Page 207
13.4 Where to Learn More......Page 208
References......Page 210
14: SEM Imaging Checklist......Page 211
14.2.3 Secondary Electrons......Page 213
14.4.4 High Resolution SEM Imaging......Page 214
14.7.2 Direction of Illumination......Page 215
14.8.2 VPSEM Disadvantages......Page 216
15: SEM Case Studies......Page 217
15.1 Case Study: How High Is That Feature Relative to Another?......Page 218
15.2 Revealing Shallow Surface Relief......Page 220
15.3 Case Study: Detecting Ink-Jet Printer Deposits......Page 222
16: Energy Dispersive X-ray Spectrometry: Physical Principles and User-Selected Parameters......Page 224
16.1.1 The Principal EDS Artifact: Peak Broadening (EDS Resolution Function)......Page 225
16.1.3 Minor Artifacts: Coincidence Peaks......Page 228
16.1.4 Minor Artifacts: Si Absorption Edge and Si Internal Fluorescence Peak......Page 230
Choosing the EDS Time Constant (Resolution and Throughput)......Page 231
Selecting a Beam Current for an Acceptable Level of System Dead-Time......Page 232
16.3.1 Detector Geometry......Page 234
16.3.3 Optimal Working Distance......Page 237
16.3.4 Detector Orientation......Page 238
16.3.5 Count Rate Linearity......Page 240
16.3.6 Energy Calibration Linearity......Page 241
16.3.7 Other Items......Page 242
16.3.8 Setting Up a Quality Control Program......Page 243
Creating a QC Project......Page 244
16.3.9 Purchasing an SDD......Page 245
Resolution and Peak Position Stability with Count Rate......Page 247
References......Page 249
17: DTSA-II EDS Software......Page 250
17.1.3 Overview......Page 251
Experiment Design......Page 252
Modeled Detectors (. Fig. 17.1)......Page 253
The Optimal Working Distance (. Figs. 17.3 and 17.4)......Page 255
Azimuthal Angle......Page 257
Dead Layer......Page 258
Material Editor Dialog (. Figs. 17.9, 17.10, 17.11, 17.12, 17.13, and 17.14)......Page 259
17.2.2 Monte Carlo Simulation......Page 260
17.2.3 Using the GUI To Perform a Simulation......Page 262
The “VP Scatter Data” Table......Page 277
References......Page 279
18: Qualitative Elemental Analysis by Energy Dispersive X-Ray Spectrometry......Page 280
Exciting Characteristic X-Rays......Page 281
X-ray Absorption......Page 282
18.2.3 Artifacts of the EDS Detection Process......Page 284
Coincidence Peaks......Page 287
18.3.1 Why are Skills in Manual Qualitative Analysis Important?......Page 290
Beam Energy......Page 292
18.4.1 Employ the Available Software Tools......Page 293
18.4.2 Identifying the Peaks: Major Constituents......Page 295
18.5 A Worked Example of Manual Peak Identification......Page 296
References......Page 302
19: Quantitative Analysis: From k-ratio to Composition......Page 303
19.1 What Is a k-ratio?......Page 304
19.3 Sets of k-ratios......Page 305
19.6 Normalization......Page 306
19.7.3 Element by Difference......Page 307
Example Calculations......Page 308
19.9.1 Standards-Based k-ratio Protocol......Page 309
19.9.2 “Standardless Analysis”......Page 310
19.10.1 The Need for Matrix Corrections To Achieve Quantitative Analysis......Page 312
19.10.3 ZAF Factors in Microanalysis......Page 313
X-ray Generation With Depth, φ(ρz)......Page 314
X-ray Absorption Effect, A......Page 317
X-ray Fluorescence, F......Page 320
References......Page 321
20: Quantitative Analysis: The SEM/EDS Elemental Microanalysis k-ratio Procedure for Bulk Specimens, Step-by-Step......Page 322
EDS Spectrum Channel Energy Width and Spectrum Energy Span......Page 324
EDS Time Constant (Resolution and Throughput)......Page 325
20.2.3 Measuring the Beam Current......Page 326
20.2.4 Choosing the Beam Current......Page 327
Optimizing Analysis Strategy......Page 329
MoS2......Page 331
20.4 The Need for an Iterative Qualitative and Quantitative Analysis Strategy......Page 332
20.4.1 Analysis of a Complex Metal Alloy, IN100......Page 333
20.4.2 Analysis of a Stainless Steel......Page 336
20.4.3 Progressive Discovery: Repeated Qualitative–Quantitative Analysis Sequences......Page 337
20.5 Is the Specimen Homogeneous?......Page 339
20.6.1 Alkali Element Migration......Page 344
Thin Section Analysis......Page 347
Bulk Biological and Organic Specimens......Page 351
References......Page 352
21: Trace Analysis by SEM/EDS......Page 353
21.1 Limits of Detection for SEM/EDS Microanalysis......Page 354
21.2.3 Estimating CDL When a Reference Value for Trace or Minor Element Is Not Available......Page 355
21.3.1 Is a Given Trace Level Measurement Actually Valid?......Page 357
NIST DTSA II Simulation: Vertical Interface Between Two Regions of Different Composition in a Flat Bulk Target......Page 358
NIST DTSA II Simulation: Cubic Particle Embedded in a Bulk Matrix......Page 360
21.4.1 Instrumental Sources of Trace Analysis Artifacts......Page 362
21.4.2 Assessing Remote Excitation Sources in an SEM-EDS System......Page 365
References......Page 369
22: Low Beam Energy X-Ray Microanalysis......Page 370
22.1 What Constitutes “Low” Beam Energy X-Ray Microanalysis?......Page 371
22.1.2 Low Beam Energy Analysis Range......Page 375
22.2.1 Improved Spatial Resolution......Page 376
22.2.3 Accurate Analysis of Low Atomic Number Elements at Low Beam Energy......Page 377
22.3.1 Reduced Access to Elements......Page 380
22.3.2 Relative Depth of X-Ray Generation: Susceptibility to Vertical Heterogeneity......Page 383
22.3.3 At Low Beam Energy, Almost Everything Is Found To Be Layered......Page 384
Analysis of Surface Contamination......Page 385
References......Page 391
23: Analysis of Specimens with Special Geometry: Irregular Bulk Objects and Particles......Page 392
23.1 The Origins of “Geometric Effects”: Bulk Specimens......Page 393
23.2.1 No Chemical Etching......Page 395
23.3 Consequences of Attempting Analysis of Bulk Materials With Rough Surfaces......Page 396
23.4.1 The Raw Analytical Total......Page 397
23.4.2 The Shape of the EDS Spectrum......Page 400
23.5 Best Practices for Analysis of Rough Bulk Samples......Page 402
23.6.1 How Do X-ray Measurements of Particles Differ From Bulk Measurements?......Page 405
23.6.2 Collecting Optimum Spectra From Particles......Page 406
Particle Sample Preparation: Bulk Substrate......Page 407
Particle Sample Preparation: Minimizing Substrate Contributions With a Thin Foil Substrate......Page 409
The Importance of Beam Placement......Page 410
23.6.3 X-ray Spectrum Imaging: Understanding Heterogeneous Materials......Page 411
“Particle Mass Effect”......Page 414
“Particle Absorption Effect”......Page 415
The Analytical Total Reveals the Impact of Particle Effects......Page 416
Does Overscanning Help?......Page 418
Specimen Geometry Severely Affects the k-ratio, but Not the P/B......Page 419
Using the P/B Correspondence......Page 420
23.7 Summary......Page 421
References......Page 422
24: Compositional Mapping......Page 423
24.1 Total Intensity Region-of-Interest Mapping......Page 424
24.1.1 Limitations of Total Intensity Mapping......Page 425
24.2 X-Ray Spectrum Imaging......Page 427
SUM Spectrum......Page 429
MAXIMUM PIXEL Spectrum......Page 431
24.3 Quantitative Compositional Mapping......Page 434
24.4.1 Choosing the EDS Dead-Time......Page 440
24.4.2 Choosing the Pixel Density......Page 442
“Flash Mapping”......Page 444
High Count Mapping......Page 446
References......Page 449
25: Attempting Electron-Excited X-Ray Microanalysis in the Variable Pressure Scanning Electron Microscope (VPSEM)......Page 450
25.1 Gas Scattering Effects in the VPSEM......Page 451
25.1.1 Why Doesn’t the EDS Collimator Exclude the Remote Skirt X-Rays?......Page 455
25.1.2 Other Artifacts Observed in VPSEM X-Ray Spectrometry......Page 457
25.2 What Can Be Done To Minimize gas Scattering in VPSEM?......Page 459
Particle Analysis......Page 460
25.2.3 Unfavorable Sample Characteristics......Page 465
References......Page 468
26: Energy Dispersive X-Ray Microanalysis Checklist......Page 469
A Faraday Cup......Page 470
26.2 Sample Preparation......Page 471
Selecting a Pulse Process Time Constant......Page 472
Maintaining the Working Distance/ Specimen-to-EDS Distance......Page 473
26.4.1 Exploratory Spectrum......Page 474
26.4.7 Collecting Spectra From the Unknown......Page 475
26.6.1 Check the Residual Spectrum After Peak Fitting......Page 476
26.6.3 Intercompare the Measurements......Page 477
Reference......Page 478
27: X-Ray Microanalysis Case Studies......Page 479
27.1 Case Study: Characterization of a Hard-Facing Alloy Bearing Surface......Page 480
27.2 Case Study: Aluminum Wire Failures in Residential Wiring......Page 482
27.3 Case Study: Characterizing the Microstructure of a Manganese Nodule......Page 484
References......Page 487
28: Cathodoluminescence......Page 488
28.1 Origin......Page 489
28.2.2 Detection of CL......Page 490
Semiconductors......Page 492
Lead-Acid Battery Plate Reactions......Page 493
References......Page 496
29: Characterizing Crystalline Materials in the SEM......Page 497
29.1.1 Single Crystals......Page 498
29.1.2 Polycrystalline Materials......Page 500
29.2 Electron Backscatter Diffraction in the Scanning Electron Microscope......Page 502
29.2.1 Origin of EBSD Patterns......Page 504
29.2.3 EBSD Spatial Resolution......Page 505
29.2.4 How Does a Modern EBSD System Index Patterns......Page 507
Sample Preparation for EBSD......Page 508
Check for EBSD Patterns......Page 509
Adjust SEM and Select EBSD Map Parameters......Page 510
29.2.6 Display of the Acquired Data......Page 511
29.2.8 Dangers and Practice of “Cleaning” EBSD Data......Page 514
29.2.9 Transmission Kikuchi Diffraction in the SEM......Page 515
Application of EBSD To Understand Meteorite Formation......Page 516
EBSD Detector......Page 519
References......Page 520
30: Focused Ion Beam Applications in the SEM Laboratory......Page 522
30.2 Ion–Solid Interactions......Page 523
30.3 Focused Ion Beam Systems......Page 524
30.4 Imaging with Ions......Page 525
30.5 Preparation of Samples for SEM......Page 526
30.5.1 Cross-Section Preparation......Page 527
30.5.2 FIB Sample Preparation for 3D Techniques and Imaging......Page 529
30.6 Summary......Page 531
References......Page 533
31: Ion Beam Microscopy......Page 534
31.1 What Is So Useful About Ions?......Page 535
31.2 Generating Ion Beams......Page 538
31.3 Signal Generation in the HIM......Page 539
31.4 Current Generation and Data Collection in the HIM......Page 541
31.5 Patterning with Ion Beams......Page 542
31.7 Chemical Microanalysis with Ion Beams......Page 543
References......Page 544
Structure of the Database......Page 546
Stopping Powers......Page 547
Reference List......Page 548
Index......Page 551