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HL: Halbleiterphysik

HL 24: Transporteigenschaften

HL 24.12: Vortrag

Mittwoch, 29. März 2000, 18:45–19:00, H14

Engineering the diffusion behavior of dopants in silicon by incorporation of carbon — •P. Lavéant, R. Scholz, N. Engler, P. Werner, and U. Gösele — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle

Carbon (C) in Silicon (Si) is a subject of high interest since it has been found that it can suppress the transient enhanced diffusion (TED), which may be detrimental for devices such as heterojunction bipolar transistors (HBT). To understand this macroscopic behavior, atomistic processes have to be analyzed. It is known that C diffuses via the kick-out mechanism. Incorporated at concentrations well above its solubility limit in Si (5×10⁽17) at melt temperature), it causes non-equilibrium concentrations of native point defects i.e. self-interstitials and vacancies. We show that an accurate description of the experimental profiles is only possible if the Frank-Turnbull mechanism, involving vacancies, is additionally taken into account

With such a model, we are able to predict the co-diffusion of C with dopants like B, Ge or Sb. We also experimentally show the reduction of the B-diffusion and the enhancement of the Sb-diffusion. The samples we used where grown by molecular beam epitaxy. Dopants where introduced as 10nm spikes within or not a C-box profile.