Dresden 2003 – wissenschaftliches Programm
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O: Oberflächenphysik
O 24: Postersitzung (Epitaxie und Wachstum, Oxide und Isolatoren, Elektronische Struktur, Oberfl
ächenreaktionen, Adsorption an Oberfl
ächen, Organische Dünnschichten)
O 24.5: Poster
Mittwoch, 26. März 2003, 14:30–17:30, P1
Nucleation and Growth of CaF2 on vicinal Si(111) — •Carsten Deiter1, Markus Bierkandt1, Joachim Wollschläger1, and Mats I. Larsson2 — 1Institut für Festkörperphysik, Universität Hannover, D-30167 Hannover, Germany — 2Department of Material Science and Engineering, Stanford University, CA 94305-4045, USA
Calcium fluoride (CaF2) is one prime candidate for the growth of ultra-thin, laminar , and epitaxial insulating films on silicon (Si). Those films are of particular interest for applications such as resonant tunneling diodes (RTD), where they serve as tunneling barriers.
We investigated the influence of substrate steps on the nucleation and growth of CaF2 on vicinal Si(111) by means of scanning tunneling microscopy (STM). It is demonstrated that substrate steps are preferred nucleation sites for submonolayer epitaxy. For deposition beyond 1ML substrate induced steps are no longer preferred nucleation sites due to the B orientation of CaF2/Si(111). Additionally, it is shown that steps can act as growth barriers.
The nucleation of CaF2 submonolayers on vicinal Si substrates is in excellent agreement with kinetic Monte-Carlo (KMC) studies. For instance, the KMC simulations verify the scaling behavior of the critical kinetic parameters for the transition from terrace to step nucleation. Furthermore, it is demonstrated that the width of the denuded zones near the step edges is given by one half of the mean distance of the terrace islands.