Atom Probe Microscopy (eBook)

PrefaceAcknowledgementsList of Acronyms and AbbreviationsList of TermsList of Non-SI Units and Constant ValuesPART I Fundamentals1. Introduction2. Field Ion Microscopy2.1 Principles2.1.1 Theory of field ionisation2.1.2 ‘Seeing’ atoms – field ion microscopy2.1.3  Spatial resolution of the FIM2.2 Instrumentation and Techniques for FIM2.2.1 FIM instrumentation2.2.2 eFIM or digital FIM2.2.3 Tomographic FIM Techniques2.3 Interpretation of FIM Images2.3.1 Interpretation of the image in a pure material2.3.2 Interpretation of the image for alloys2.3.3 Selected applications of the FIM2.3.4 Summary3 From Field Desorption Microscopy to Atom Probe Tomography3.1 Principles3.1.1 Theory of field evaporation3.1.2 ‘Analysing’ atoms one-by-one: atom probe tomography3.2 Instrumentation and Techniques for APT3.2.1 Experimental setup3.2.2 Field desorption microscopy3.2.3 High voltage pulsing techniques3.2.4 Laser pulsing techniques3.2.5 Energy compensation techniquesPart II Practical aspects4. Specimen Preparation4.1 Introduction4.1.1 Sampling issues in microscopy for materials science and engineering4.1.2 Specimen requirements4.2 Polishing methods4.2.1 The electropolishing process4.2.2 Chemical polishing4.2.3 Safety Considerations4.2.4 Advantages and limitations4.3 Broad ion beam techniques4.4 Focused ion beam techniques4.4.1 Cut-away methods4.4.2 Lift-out methods4.4.3 The final stages of FIB preparation4.4.4 Understanding and minimising ion beam damage and other artefacts4.5 Deposition methods4.6 Methods for organic materials4.6.1 Polymer microtips4.6.2 Self-assembled monolayers4.6.3 Cryopreparation4.7 Other Methods4.7.1 Dipping4.7.2 Direct growth of suitable structures4.8 Specimen geometry issues4.8.1 Influence of specimen geometry on atom probe data4.8.2 Stress states and specimen rupture4.9 A guide to selecting an appropriate specimen preparation method5. Experimental protocols in Field Ion Microscopy5.1 Step-by-step procedures for FIM5.2 Operational space of the field ion microscope5.2.1 Imaging gas5.2.2 Temperature5.2.3 The best image field5.2.4 Other parameters5.2.5 Summary6. Experimental protocols6.1 Specimen alignment6.2 Aspects of mass spectrometry6.2.1 Detection of the ions6.2.2 Mass spectra6.2.3 Formation of the mass spectrum6.2.4 Mass resolution6.2.5 Common artefacts6.2.6 Elemental identification6.2.7 Measurement of the composition6.2.8 Detectability6.3 Operational space6.3.1 Flight path6.3.2 Temperature / Pulse fraction6.3.3 Selecting the pulsing mode6.3.4 Pulse rate6.3.5 Detection rate6.4 Specimen failure6.5 Data quality assessment6.5.1 Field desorption map6.5.2 Mass spectrum6.5.3 Multiple events6.5.4 Discussion7. Tomographic reconstruction7.1 Projection of the ions7.1.1 Estimation of the electric field7.1.2 Field distribution7.1.3 Ion trajectories7.1.4 Point projection7.1.5 Radial projection with angular compression7.1.6 Discussion7.2 Reconstruction7.2.1 General considerations7.2.2 Bas et al. protocol7.2.3 Geiser et al. protocol7.2.4 Gault et al. protocol7.2.5 Reflectron-fitted instruments7.2.6 Summary and discussion7.3 Calibration of the parameters7.3.2 Discussion7.3.3 Limitations of the current procedure7.4 Common artefacts7.4.2 Correction of the reconstruction7.5 Perspectives on the reconstruction in atom probe tomography7.5.1 Advancing the reconstruction by correlative microscopy7.5.2 In correlation with simulations7.5.3 Alternative ways to exploit existing data7.6 Spatial resolution in APT7.6.1 Introduction7.6.2 Means of investigation7.6.3 Definition7.6.4 On the in-depth resolution7.6.5 On the lateral resolution7.6.6 Optimisation of the spatial resolution7.7 Lattice rectificationPART III Applying atom probe techniques for materials science8. Analysis techniques for atom probe tomography8.1 Characterising the Mass Spectrum8.1.1 Noise Reduction8.1.2 Quantifying Peak Contributions via Isotope Natural Abundances8.1.3 Spatially dependent identification of mass peaks8.1.4 Multiple Detector Event Analyses8.2 Characterising the chemical distribution8.2.1 Quality of atom probe data8.2.2 Random comparators8.3 Grid-based counting statistics8.3.1 Voxelisation8.3.2 Density8.3.3 Concentration analyses8.3.4 Smoothing by delocalisation8.3.5 Visualisation techniques based on iso-concentration and iso-density8.3.6 One-dimensional profiles8.3.7 Grid-based frequency distribution analyses8.4 Techniques for describing atomic architecture8.4.1 Nearest neighbour distributions8.4.2 Cluster Identification Algorithms8.4.3 Detection Efficiency Influence on Nanostructural Analyses8.5 Radial Distribution8.5.1 Radial distribution and pair correlation functions8.5.2 Solute Short Range Order Parameters8.6 Structural Analyses8.6.1 Fourier Transforms for APT8.6.2 Spatial Distribution Maps8.6.3 Hough Transform9. Atom probe microscopy and materials science9.1 Compositional analysis9.2 Defects/ dislocations9.3 Solid solutions / clustering9.4 Precipitates9.5 Ordering reaction9.6 Spinodal decomposition9.7 Interface/boundaries/layers9.8 Amorphous materials9.9 Atom probe crystallographyAppendicesA. Appendix – χ2 distributionB. Appendix – Polishing chemicals and conditionsC. File formats used in APTPOSEPOSRNGRRNGATOENVPoSAPCameca root files – RRAW, RHIT, ROOTD. Appendix – Image Hump Model PredictionsE. Appendix – Essential Crystallography for APTBravais latticesNotationStructure factor (F) rules for BCC, FCC, HCPInterplanar spacings (dhkl)Interplanar angles (φ)F. Stereographic Projections and commonly observed desorption mapsStereographic projection for the most commonly found structures and orientationsFace-centred cubicBody-centred cubicDiamond cubicHexagonal close-packedG. Periodic tablesH. Kingham CurvesI. List of elements and associated mass to charge ratiosJ. Possible element identity of peaks as a function of their location in the mass spectrum