Investigation of Sample Deformation in Laser-Assisted Atom Probe Tomography

Abstract

Atom probe tomography (APT) is a three-dimensional (3D) analysis technique employed in science and engineering, offering information on the chemical compositions and atomic-scale structures of materials. A new technique called laser-assisted APT has been developed, in which a pulsed laser is used as a trigger for field evaporation instead of a pulsed high voltage (HV), allowing analysis of low-conductivity materials. However, in laser-assisted APT, the sample shape changes from the hemisphere to the non-hemisphere during measurement, which degrades the reconstruction accuracy. Here, to clarify the cause of sample deformation and improve the reconstruction accuracy, we studied the relationship between thermal diffusivity and the deformation degree. Our experimental results demonstrate that the sample deformation degree is inversely proportional to the thermal diffusivity, indicating that the sample heating by the irradiated pulsed laser is non-negligible and has a considerable impact on sample deformation in laser-assisted APT.