Regensburg 2010 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 31: Poster I: Devices, Quantum Dots and Quantum Wires
HL 31.47: Poster
Tuesday, March 23, 2010, 18:30–20:30, Poster D1
Electrically active dopant profiles in individual silicon nanowires — •Pratyush Das Kanungo1, Xin Ou1,2, Reinhard Kögler2, Peter Werner1, Ulrich Gösele1, and Wolfgang Skorupa2 — 1Max Planck Institute of Microstructure Physics, Weinberg 2, Halle D-06120, Germany — 2Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf e.V., P.O. Box 510119, 01314 Dresden, Germany
Controlled doping and profiling of electrically active dopants in individual silicon nanowires (Si NWs) are two important factors that can decide the use of Si NWs as future building blocks in nano-electronics. We have investigated individual Si NWs doped either by ion implantation or by in-situ dopant incorporation during growth via molecular beam epitaxy, by scanning spreading resistance microscopy (SSRM). In case of the phosphorus ion-implanted and subsequently annealed NWs the SSRM profiles revealed a radial core-shell distribution of the activated dopants. The maximum carrier concentration close to the surface of a phosphorus-doped NW was found to be by a factor of 6-7 higher than the value in the core, and on average only 25% of the implanted phosphorus was electrically active. In contrast, for the in-situ boron-doped NW, the activation rate of the boron atoms was significantly higher than for phosphorus atoms, and the carrier profile was relatively flat over the NW diameter.