Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 68: Heterostructures and interfaces
HL 68.2: Talk
Wednesday, April 2, 2014, 15:15–15:30, POT 051
Early stages of nucleation in Cu/a-Si system — •Mohammed Ibrahim1, Zoltán Balogh1, Dietmar Baither1, Patrick Stender1, and Guido Schmitz2 — 1Institut für Materialphysik, University of Münster — 2Institut für Materialwissenschaft, Universität Stuttgart
Laser-assisted atom probe shows a unique potential in the analysis of embedded Si/metal interfaces, owing to its ability to deliver 3D chemical mapping with near atomic resolution. It is therefore a complementary part to the 2D electron microscopic methods [1]. Recently, we observed that the reaction between Cu and a-Si to form silicide phases is strongly influenced by the deposition sequence. From that, if Cu deposited on a-Si, an instantaneous reaction happens at low temperature and a reacted layer increases linearly with increasing annealing time [2]. For the reverse case, high temperatures or long annealing time are required for the appearance of silicide at the interface [3]. In this work, we focus on the phase nucleation with higher nucleation barrier in case of a-Si deposited upon Cu. We observed an increase of roughness at the interface, the appearance of Cu rich particles in the a-Si bulk as well as spikes of high Cu contents protruding from the metallic Cu. As opposed to previous reports [4], these findings indicate that a significant nucleation barrier exists for nucleating the silicide at the interface. Nucleation happens at the a-Si side probably even inside the Si bulk.
[1] R. Schlesiger et al., Rev. Sci. Instrum., 81 (2010) 043703. [2] B. Parditka et al., Acta Mater., 61 (2013) 7173. [3] M. Ibrahim, et. al, Phys. Stat. Sol. C, DOI: 10.1002/pssc.201300370. [4] F. Hodaj , and. A. Gusak, Acta Mater., 52 (2004) 4305.