Speaker
Description
This study focuses on the influence of laser wavelength and pulse energy on the elemental accuracy of atom probe tomography (APT) analysis of stoichiometric TiN coatings. By utilizing three different commercial atom probe systems — LEAP 3000X HR, LEAP 5000 XR, and LEAP 6000 XR — it is illuminated how short laser wavelengths, especially those in the deep ultraviolet (DUV) range, impact the evaporation behavior and the precision of the measurements. The findings demonstrate that shorter wavelengths result in enhanced elemental accuracy by minimizing the laser pulse energy while maintaining consistent electric field strengths, thus reducing thermal effects that typically degrade the mass resolving power. These improvements are critical to achieve accurate and reliable compositional data, particularly in materials where maintaining structural integrity during analysis is essential.
In addition, an analysis of the energy density ratios across the three atom probe systems is presented, highlighting that shorter wavelengths correlate with smaller laser spot sizes and consequently higher energy densities. These increased energy densities, while potentially resulting in higher heat input, are confined to a smaller region at the apex of the specimen. This allows for faster cooling rates, minimizing thermal diffusion and surface migration, both of which are detrimental to the elemental accuracy of APT measurements.
Furthermore, advancements in detector technology were evaluated to assess their role in improving measurement accuracy. Detector dead-times and dead-zones were thoroughly analyzed to understand their effect on ion pile-up behavior, which can compromise the accuracy of APT measurements. The results showed that while the improvements in detector technology enhance the overall system performance, the reduction in laser wavelength plays a more significant role in improving the elemental accuracy.
