Münster 1999 – scientific programme

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HL: Halbleiterphysik

HL 23: Poster II

HL 23.28: Poster

Wednesday, March 24, 1999, 14:00–18:00, Z

Non equillibrium effects during carbon out-diffusion in silicon. — •P. Laveant, R.F. Scholz, P. Werner, and U. G"osele — Max-Planck-Institut f"ur Mikrostrukturphysik, Weinberg 2, 06120 Halle

Diffusion of carbon is mostly assumed to be governed by carbon interstitials via the kick-out mechanism. Carbon in-diffusion experiments are associated with thermal equilibrium concentrations of point defects, whereas in the case of carbon out-diffusion a remarkable undersaturation of Si self-interstitials may develop provided the carbon

concentration is several orders of magnitude over its solubility value. New carbon out-diffusion experiments demonstrate that this model qualitatively describes the observed carbon diffusion profiles. However, we demonstrate that an accurate description of the experimental profiles is only possible if the Frank-Turnbull mechanism, involving vacancies, is additionally taken into account.

Carbon and boron profiles in one sample and carbon and antimony profiles in an other sample where investigate by SIMS. The samples where grown by molecular beam epitaxy. Boron and antimony where introduced as 10nm spikes to determine the non-equillibrium behavior of the silicon self-interstials with boron and the non-equillibrium behavior of the silicon vacancy with antimony.

The data can be used to determine the splitting of the known vacancy component of silicon self-diffusion coefficient into the vacancy diffusion coefficient and the vacancy thermal equilibrium concentration.