SKM 2021 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 6: Topical Session Interface-Dominated Phenomena - Thermodynamics

MM 6.2: Talk

Wednesday, September 29, 2021, 10:30–10:45, H8

Methods for Gibbs triple junction excess determination: Ti segregation in CoSi2 thin film — •Hannes Zschiesche, Ahmed Charai, Claude Alfonso, and Dominique Mangelinck — CNRS, IM2NP, Faculté de Saint-Jérôme, Aix-Marseille Université, Marseille, France

Triple junctions (TJs) are present in poly crystalline material where three grain boundaries join together. They influence directly the thermodynamics and kinetics of the material and thereby its properties. Thus, their description by geometric and thermodynamic parameters is of great interest. One of these parameters is the Gibbs TJ segregation excess. Eich et al., Acta Mater, 2018 predicted TJ excess in a Fe-Cr alloy based on simulations. However, to compare such predictions on experimentally acquired TJs methods are needed for the determination of Gibbs TJ segregation excess.

We propose methods to determine Gibbs TJ segregation excess in an atomically resolved 3D volume where single atom counting is possible, as provided by atom probe tomography (APT). Firstly, we test the methods on a simulated model volume in which the excess value is known. Further, we investigate an APT volume of CoSi2 thin film that contains three grain boundaries and a TJ which show segregation of Ti. CoSi2 is well known as contact material in microelectronics and can grow in epitaxy on Si by the introduction of a Ti interlayer. The developed methods allow to quantify the Ti excess at the CoSi2 TJ.

This work offers new possibilities for fundamental characterization of materials and an example of its application.