Oberdorfer, Christian: Numeric simulation of atom probe tomography. 2014
Inhalt
- 1 Introduction
- 2 Background: Atom Probe Microscopy
- 2.1 Field emission
- 2.1.1 Historic context: field electron emission
- 2.1.2 Field ion emission
- 2.1.3 Field desorption and field evaporation
- 2.2 Basic principles of atom probe tomography
- 2.2.1 Sample geometry and image formation
- 2.2.2 Field desorption experiments
- 2.2.3 Outline of the APT measurement process
- 2.2.4 Constitution of the 3D reconstruction
- 2.2.5 Enhanced reconstruction approach dedicated to wide angle instruments
- 2.3 Present challenges
- 3 Numeric and algorithmic prerequisites
- 3.1 Foundations of mesh generation
- 3.1.1 Geometric convexity
- 3.1.2 Properties of simplices
- 3.1.3 Delaunay tessellation
- 3.1.4 Voronoi tessellation
- 3.2 Discrete solution of the Poisson equation in electrostatics
- 3.3 Ion trajectories and the electric field
- 4 Implemented simulation approaches
- 4.1 Basic model according to Vurpillot's approach
- 4.1.1 Increasing numeric resolution
- 4.1.2 Distinguished evaporation thresholds
- 4.1.3 Statistic evaporation
- 4.1.4 Extension to include dielectricity
- 4.1.5 Discussion
- 4.2 New generalized approach
- 5 Imaging characteristics of detector events
- 5.1 Field properties and trajectories
- 5.1.1 Field factor
- 5.1.2 Image compression
- 5.1.3 Interdependence of surface field and image compression
- 5.2 Detector event maps
- 5.3 Statistic desorption under the influence of temperature
- 6 Quality of the 3D reconstruction
- 7 Evaluation of model emitter structures
- 7.1 Exerted stress on an embedded particle
- 7.2 Simulated evaporation of a complex multi-layer structure
- 7.2.1 Curvature changes at the apex
- 7.2.2 Consistent control of the evaporation sequence
- 7.2.3 Additional information required for direct comparison with experimental data
- 7.3 Investigation of a grain boundary in copper
- 8 Conclusion
- A Derivation of the discrete Poisson equation on the regular mesh
- B Computing the electric field on the irregular mesh (2nd order)
- Bibliography