Dresden 2011 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
HL: Fachverband Halbleiterphysik
HL 19: Silicon and Germanium
HL 19.7: Talk
Monday, March 14, 2011, 16:00–16:15, POT 251
In-situ incorporation and distribution of boron dopants in silicon nanowires — •Pratyush Das Kanungo1, Xin Ou2, Reinhard Koegler2, Alexander Tonkikh1, Wolfgang Skorupa2, and Peter Werner1 — 1Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germnay — 2Forschungszentrum Dresden - Rossendorf, FWIM, 01314 Dresden, Germany
Silicon nanowires (Si NWs) are promising candidates for future nanoelectronic devices and circuits. However, controlled doping and measurement of doping profiles are two of the biggest challenges that need to be addressed before using them as building blocks for functional devices. By measuring the current-voltage characteristics of a molecular beam epitaxy-grown and heavily in-situ boron-doped Si NW of diameter around 100 nm, and separately measuring the local spreading resistance across the cross-section of a NW of the same doping level, we have analyzed the incorporation, distribution and deactivation of boron atoms. It was observed that the incorporated and active boron atoms form a multi-shell structure. The area very near (around 5 nm) to the outer surface is fully depleted of active dopants because of the surface states existing at the outer surface of the NW. Underneath this depleted shell, two heavily doped cores are formed. The first one is relatively thinner (around 30 nm), but it contains relatively higher active boron concentration than the thicker (around 70 nm) inner core. We further establish that this nonuniformity in active boron concentration is related to the in-situ doping process itself which can offer two different pathways for incorporation of boron.