Regensburg 2019 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 24: Topical session (Symposium MM): Correlative and in-situ Microscopy in Materials Research

MM 24.3: Talk

Wednesday, April 3, 2019, 11:00–11:15, H45

In Situ and Ex Situ Electron Microscopy Studies of Al-Si Alloying at Grain Boundaries — •Christoph Flathmann¹, Hendrik Spende², Tobias Meyer¹, Patrick Peretzki¹, and Michael Seibt¹ — ¹4th Institute of Physics - Solids and Nanostructures, University of Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen, Germany — ²Institute of Semiconductor Technology, Braunschweig University of Technology, Hans-Sommer-Straße 66, 38106 Braunschweig, Germany

During alloying of thin aluminium (Al) layers with bulk multicrystalline (mc) silicon (Si), Al entirely melts at temperatures above 660 ^∘C whilst Si remains solid. Since a surplus of Si is available, the equilibrium concentration of the melt is given by the silicon-rich liquidus line at the corresponding temperature. Thus, a thermodynamic driving force for silicon dissolution is present. However, for mc Si, grain boundaries are sites of preferred dissolution. Hence, uneven dissolution is expected in mc material.

Employing scanning electron microscopy (SEM) and electron beam induced current (EBIC), preferential dissolution, at both low symmetry grain boundaries and 111 twin boundaries, is observed for ex situ alloyed samples. Correlating SEM and EBIC signals allows for visualising the dependence of dissolution depth on electrical junction formation. Furthermore, the dynamics of preferential dissolution are studied by in situ TEM heating experiments of 111 twin boundaries.