Berlin 2015 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 36: Poster Session I

DS 36.90: Poster

Donnerstag, 19. März 2015, 09:30–12:00, Poster A

CEMS study of iron silicide formation on silicon surfaces induced by surfactant sputtering — Clemens Beckmann, •Christoph Brüsewitz, Omar Bobes, Ulrich Vetter, and Hans Hofsäss — Georg-August-Universität Göttingen, II. Physikalisches Institut, Göttingen,Germany

We investigate ripple pattern formation on Si during normal incidence ion beam erosion under simultaneous co-deposition of Fe surfactant atoms. In previous work we proposed that chemical interaction between Fe and Si and phase separation towards a disilicide phase of the mixed Fe_xSi_1−x surface layer is a dominant contribution to self-organized pattern formation [1,2,3]. Isotopically enriched ⁵⁷Fe is used as surfactant and the generated patterns were analyzed with conversion electron Mössbauer spectroscopy (CEMS) in addition to RBS and AFM. Samples were irradiated with keV Ar and Xe ions at normal incidence and simultaneous ⁵⁷Fe co-deposition. CEMS measurements show a quadrupole splitting of 0.65(1) mm/s and isomer shift of 0.18(1) mm/s, typical for amorphous Fe_xSi_1−x. From a comparison with literature data, quadrupole splitting and isomer shift are consistent with a composition x = 0.3-0.35 and support phase separation as relevant mechanism.

[1] K. Zhang et al., New.J.Phys. 13,013033(2011).

[2] H. Hofsäss et al., AIP Advances 2,032123(2012).

[3] H. Hofsäss et al., Appl.Phys.A: Mat.Sci.Proc. 111,653 (2013).