Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 87: Metal Substrates: Structure, Epitaxy and Growth
O 87.12: Vortrag
Donnerstag, 10. März 2016, 18:00–18:15, S053
Growth, morphology, and stoichiometry of cobalt germanide islands on Ge(001) — •Moritz Ewert1, Thomas Schmidt1, Inga Heidmann1, Jan Ingo Flege1, Tomasz Grzela2, Michael Foerster3, Lucia Aballe3, Thomas Schroeder2, and Jens Falta1 — 1Institute of Solid State Physics, University of Bremen, Germany — 2Leibniz Institute for Innovative Microelectronics (IHP), Frankfurt (Oder), Germany — 3ALBA CELLS, Barcelona, Spain
In today’s silicon technology, the integration of germanium structures is one of the most promising routes to improve the performance of CMOS devices. One of the challenges is the fabrication of low-resistance metal/Ge contacts. As metallization contact materials, Co germanides and Ni germanides are regarded to have the best perspective.
We have investigated the growth of Co germanide on Ge(001) by Co metal deposition using low-energy electron microscopy and microdiffraction as well as x-ray absorption photoemissionmicroscopy (XAS). Both for room temperature (RT) deposition followed by thermal annealing as well as for metal deposition at elevated temperatures, we observe the formation of Co germanide 3D islands. Extremely anisotropic, needle-like 3D islands extending in {110} directions coexist with rather compact ones. XAS measurements at the Co L absorption edge show that for deposition at room temperature, metallic Co is present on the surface that reacts with the Ge during subsequent thermal annealing. The Co germanide forms 3D Volmer-Weber islands. Interestingly, local XAS reveals that different island morphologies are related to different germanide stoichiometries.