A Bottom-Up Volume Reconstruction Method for Atom Probe Tomography.

Area of Science:

• Materials Science
• Analytical Chemistry
• Physics

Background:

• Atom probe tomography (APT) is a powerful technique for 3D material analysis.
• Conventional reconstruction methods often struggle with complex tip morphologies and changing experimental conditions.
• Inhomogeneities in laser absorption, heat diffusion, and material properties can significantly affect the tip shape during APT.

Purpose of the Study:

• To develop a robust bottom-up reconstruction method for APT.
• To address limitations of existing methods, particularly concerning tip morphology, field of view, and detector efficiency.
• To improve the accuracy of 3D reconstructions in APT.

Main Methods:

• A bottom-up reconstruction approach starting from the final tip morphology.
• Pseudo-deposition of small reconstruction volumes to reverse the evaporation sequence.
• Trajectory-matching using simulated and experimental hit maps within reconstruction volumes.
• Detailed electrostatic modeling for simulating ion trajectories without simplifications.

Main Results:

• The proposed method successfully accounts for the final tip morphology, limited/changing field of view, and detector efficiency.
• Subdivision into small volumes allows adaptation to evolving tip shape and field of view.
• Demonstrated superior performance compared to the conventional reconstruction method (Bas) for asymmetrical tip shapes.

Conclusions:

• The novel bottom-up APT reconstruction method offers improved accuracy and robustness.
• This approach is particularly advantageous for analyzing samples with complex or asymmetrical tip shapes.
• The method provides a more reliable way to reconstruct 3D atomic structures from APT data.