Dresden 2009 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 26: Focused Session: Novel nanowires electronic device concepts

HL 26.2: Topical Talk

Mittwoch, 25. März 2009, 10:00–10:30, HSZ 01

Doping limits in silicon nanowires — •Mikael Björk, Heinz Schmid, Joachim Knoch, Heike Riel, and Walter Riess — IBM Research GmbH, Ruschlikon, Switzerland

The operation of electronic devices relies heavily on the density of free charge carriers available in the semiconductor, a quantity that is usually well controlled by the addition of dopant atoms. The fabrication of ultimately scaled semiconductor devices will thus depend significantly on the ability to precisely control the location and number of active impurity atoms in the host semiconductor. As dimensions are scaled down the presence of interfaces and materials adjacent to the semiconductor become more important and can eventually completely determine the electronic properties of the device. Here we experimentally demonstrate the in-situ doping limits of silicon nanowires and that the free carrier density in nanoscale semiconductor wires is size dependent due to a reduction in the amount of ionized impurities. By measuring the electrical conduction of doped silicon nanowires as a function of wire radius, temperature and dielectric surrounding we present experimental proof of a deactivation of the doping atoms in the wires, which is due to a dielectric mismatch between the nanowire core and the surrounding.