1 Introduction and Outline .....................................
1.1 Historical Background ...................................
1.1.1 X-Ray-Induced Photoelectron Spectroscopy (XPS) ... 2
1.1.2 Auger Electron Spectroscopy (AES) ................ 3
1.2 Outline of Electron Spectroscopy ........................ 5
1.2.1 Outline of X-Ray Photoelectron Spectroscopy
(XPS) ............................................
1.2.2 Outline of Auger Electron Spectroscopy (AES)
1.3 State of the Art and Future Development ................. 8
References ..............................................
Instrumentation ........................................
2.1 Vacuum System ...........................................
2.1.1 Basic Pressure Requirements ..................... 13
2.1.2 Attainment and Maintenance of Ultrahigh
Vacuum (UHV) .................................... 15
2.2 X-Ray Source ...........................................
2.2.1 Conventional X-Ray Source ....................... 18
2.2.2 Monochromatic X-Ray Source ...................... 19
2.2.3 Small-Spot X-Ray Source and Scanning XPS
Microscopy ......................................
2.2.4 Synchrotron X-Ray Source ........................ 22
2.3 Electron Gun ...........................................
2.4 Ion Gun ................................................
2.5 Electron Energy Analyzer ............................... 29
2.5.1 The Cylindrical Mirror Analyzer (CMA) ........... 30
2.5.2 The Concentric Hemispherical Analyzer (СНА) ..... 33
2.5.3 Multichannel Detection .......................... 36
2.5.4 Imaging XPS ..................................... 3^
2.6 Software ............................................... 42
References ..................................................
3 Qualitative Analysis (Principle and Spectral
Interpretation) ............................................. 43
3.1 Introduction: Notation of Atomic Electron Levels ....... 43
3.2 Qualitative XPS ........................................ 43
3.2.1 Principle of XPS Analysis ....................... 43
3.2.2 Photoelectron Spectra: Elemental
Identification .................................. 45
3.2.3 Chemical Shift of Photoelectron Peak Energy ..... 48
3.2.4 Auger Parameter ................................. 49
3.2.5 Valence Band Spectra ............................ 52
3.2.6 Satellite Peaks ................................. 52
3.2.7 XPS Line Shapes ................................. 54
3.2.8 Emission Angle Effects .......................... 58
3.3 Qualitative AES ........................................ 63
3.3.1 Principle of AES Analysis ....................... 63
3.3.2 Auger Spectra and Elemental Identification ...... 64
3.3.3 Direct and Derivative Spectra ................... 66
3.3.4 Recognition and Influence of Chemical Bonding ... 68
3.3.5 Electron Backscattering, Channeling, and
Diffraction ..................................... 71
References .................................................. 74
4 Quantitative Analysis (Data Evaluation) ..................... 77
4.1 Measurement and Determination of Intensities ........... 77
4.1.1 Background Subtraction .......................... 79
4.1.2 Differential (Derivative) Spectra (APPH in
AES) ............................................ 81
4.1.3 Decomposition of Overlapping Peaks .............. 83
4.1.4 Factor Analysis and Principal Component
Analysis ........................................ 83
4.2 Quantification Using Intensities ....................... 84
4.2.1 Quantification Principles Using Elemental
Relative Sensitivity Factors (E-RSFs) ........... 84
4.2.2 Key Parameters: Inelastic Mean Free Path
(IMFP) and Effective Attenuation Length (EAL) ... 87
4.3 Quantitative XPS ...................................... 104
4.3.1 Fundamental Quantities for XPS ................. 104
4.3.2 Quantitative XPS Analysis of Homogeneous
Material ....................................... 109
4.3.3 Quantitative XPS Analysis of Thin Surface
Layers ......................................... 135
4.4 Quantitative AES ...................................... 172
4.4.1 Fundamental Quantities for AES ................. 172
4.4.2 Quantitative AES Analysis of Homogeneous
Material ....................................... 179
4.4.3 Quantitative AES Analysis of Thin Surface
Layers ......................................... 189
4.5 Summary and Conclusion ................................ 200
References ................................................. 201
5 Optimizing Measured Signal Intensity: Emission Angle,
Incidence Angle and Surface Roughness ...................... 205
5.1 XPS: Intensity Dependence on Emission and Incidence
Angles ................................................ 205
5.1.1 Sample Tilt Using СНА .......................... 208
5.1.2 Double-Pass Cylindrical Mirror Analyzer
(DP-CMA) and Thetaprobe (СНА) .................. 209
5.1.3 Total Reflection XPS (TR-XPS) .................. 213
5.1.4 XPS Intensity Dependence on Surface Roughness .. 214
5.2 AES: Intensity Dependence on Emission and Incidence
Angles ................................................ 227
5.2.1 Sample Tilt Using СНА for AES .................. 227
5.2.2 Sample Tilt Using CMA .......................... 235
5.2.3 AES Intensity Dependence on Surface Roughness .. 239
5.3 Summary and Conclusion ................................ 255
References ................................................. 256
6 Optimizing Certainty and the Detection Limit: Signal-to-
Noise Ratio ................................................ 259
6.1 Introduction and Definitions for Pulse-Counting
Systems ............................................... 259
6.1.1 Definitions and Explanations ................... 260
6.1.2 Role of Peak-to-Background (P/B) Ratio ......... 263
6.2 Parameters Affecting Р/В and Singal-to-Noise (S/N)
Ratios ................................................ 266
6.2.1 Emission and Incidence Angle Dependencies
of Р/В and S/N for XPS and AES ................. 266
6.2.2 Analyzer Resolution ............................ 270
6.2.3 Surface Roughness .............................. 275
6.2.4 Detector Efficiency and Scattered Electrons .... 275
6.2.5 Excitation Intensity (Primary Beam Current)
and Total Measurement Time per Channel ......... 275
6.2.6 Detection Limit ................................ 279
6.2.7 S/N Ratio and Uncertainty in Peak
Measurements ................................... 281
6.2.8 S/N in Multichannel Detection .................. 286
6.2.9 Uncertainty in Quantified Data and Strategy
for Data Acquisition ........................... 289
6.3 S/N Ratio for Analog Systems .......................... 293
References ................................................. 295
7 Quantitative Compositional Depth Profiling ................. 297
7.1 Sputter Depth Profiling ............................... 298
7.1.1 Instrumentation and Experimental Setup ......... 298
7.1.2 Basic Quantification of Composition and
Sputtered Depth ................................ 302
7.1.3 Depth Resolution: Definition and Measurement ... 314
7.1.4 Factors Limiting Depth Resolution and Profile
Accuracy ....................................... 319
7.1.5 Depth Dependence of Depth Resolution:
Superposition of Different Contributions ....... 338
7.1.6 Optimized Depth Profiling Conditions ........... 339
7.1.7 Modeling, Deconvolution, and Reconstruction
of Depth Profiles .............................. 344
7.1.8 The MRI Model and Its Modifications ............ 348
7.1.9 Special Sputter Depth Profiling Techniques ..... 371
7.2 Nondestructive Depth Profiling ........................ 382
7.2.1 Angle-Resolved XPS and AES ..................... 382
7.2.2 Depth Profiling by Variation of the
Excitation Energy .............................. 398
7.2.3 Depth Profiling Using Background Information
(Peak-Shape Analysis) .......................... 400
7.3 Conclusion: Comparison of Nondestructive and
Destructive Depth Profiling Methods ................... 402
References ................................................. 402
8 Practice of Surface and Interface Analysis with AES and
XPS ........................................................ 409
8.1 Analytical Strategy ................................... 409
8.2 Sample Properties ..................................... 411
8.2.1 Type of Material ............................... 411
8.2.2 Size, Shape, Morphology, and Roughness ......... 412
8.2.3 Inhomogeneous Structure and Composition ........ 412
8.2.4 Electrical Conductivity ........................ 413
8.2.5 Likelihood of Electron- or Photon-Beam-
Induced Damage ................................. 413
8.3 Sample Preparation .................................... 414
8.3.1 Outside ("Ex Situ") Preparation ................ 414
8.3.2 Inside ("In Situ") Preparation ................. 417
8.4 Setting Up the Instrument and Measurement ............. 420
8.4.1 Calibration of the Energy and Intensity
Scales ......................................... 420
8.4.2 Mounting and Alignment of the Sample ........... 422
8.4.3 Measurement Sequence ........................... 423
8.5 AES and XPS on Insulators ............................. 424
8.5.1 Charging and Charge Compensation in XPS ........ 424
8.5.2 Charging and Charge Compensation in AES ........ 426
8.6 Electron and Photon-Beam Damage During AES
and XPS Analyses ...................................... 434
8.6.1 AES: Electron Beam Stimulated Changes
in Composition and Structure ................... 435
8.6.2 XPS: X-Ray-Induced Changes in Composition ...... 441
References ................................................. 446
9 Typical Applications of AES and XPS ........................ 451
9.1 Ex Situ Sample Preparation ............................ 451
9.1.1 Coatings and Layered Structures ................ 452
9.1.2 Corrosion and High-Temperature Oxidation ....... 454
9.1.3 Interfacial Reactions and Diffusion ............ 460
9.1.4 Interfacial Segregation ........................ 460
9.1.5 Implantation Layers ............................ 465
9.1.6 Further Methods and Materials .................. 468
9.2 In Situ Sample Preparation ............................ 469
9.2.1 Surface Layer Formation by Deposition .......... 469
9.2.2 Early Stages of Oxidation ...................... 471
9.2.3 Altered Layers by Ion Bombardment .............. 476
9.2.4 Deposited Layer Structure ...................... 479
9.2.5 Surface Segregation ............................ 479
9.3 Treatment of AES and XPS Data by Factor Analysis ...... 481
References ................................................. 482
10 Surface Analysis Techniques Related to AES and XPS ......... 487
10.1 Overview of Surface Analysis Methods .................. 487
10.2 Photon-Beam Excitation ................................ 488
10.2.1 Detection of Photons ........................... 488
10.2.2 Detection of Electrons ......................... 489
10.2.3 Detection of Ions and Neutral Particles ........ 490
10.3 Electron-Beam Excitation .............................. 491
10.3.1 Detection of Photons ........................... 491
10.3.2 Detection of Electrons ......................... 491
10.3.3 Detection of Ions and Neutrals ................. 494
10.4 Ion-Beam Excitation ................................... 494
10.4.1 Detection of Photons ........................... 494
10.4.2 Detection of Electrons ......................... 495
10.4.3 Detection of Ions and Neutrals ................. 495
10.5 Excitation by Electric Field or Heat .................. 497
10.5.1 Detection of Photons ........................... 497
10.5.2 Detection of Electrons ......................... 497
10.5.3 Detection of Ions and Neutral Particles ........ 498
10.5.4 Detection of Forces ............................ 498
10.6 Comparison of the Principal Surface Chemical
Analysis Techniques ................................... 499
10.6.1 Main Features of AES, XPS, SIMS and ISS ........ 499
10.6.2 Combination of Techniques ...................... 501
References ............................................ 501
Index ......................................................... 505
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