Dresden 2009 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 30: Si/Ge
HL 30.5: Talk
Wednesday, March 25, 2009, 10:30–10:45, POT 51
Doping of vertical silicon nanowires by ion implantation — •Pratyush Das Kanungo1, Reinhard Kögler2, Nikolai Zakharov1, Kien Ngyuen-Duc1, Peter Werner1, and Ulrich Gösele1 — 1Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany — 2Forschungszentrum Dresden - Rossendorf, FWIM, 01314 Dresden, Germany
Ion implantation is one of the key processing steps in fabricating planar silicon devices and circuits in the ultra large scale integration (ULSI) technology. With ion implanatation one can selectively dope specific areas on a planar silicon device defined by lithographic masks and confine the vertical penetration depth of the dopant atoms into the bulk of silicon at that region. However, this process has so far not been fully exploited in nanoelectronics, especially in doping silicon nanowires (Si NWs). Si NWs which are promising candidates for future nanoelectronics have mostly been doped in situ. We demonstrate that ion implantation can also effectively dope vertical Si NWs both n and p-type. We implanted boron as p-type dopant, and separately phosphorus and arsenic as n-type dopants on the Si NWs grown by molecular beam epitaxy. We demonstrate homogeneous doping [1] along the length of the NWs, as well as formation of an axial p-n junction inside the NWs and performed detailed structural and electrical characterizations of individual NWs. For the p-n junction formation a combined approach of in situ p-doping [2] and ex situ n-doping was used. Our results show significant differences between n and p-doping which conform to theory.