Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 73: Devices

HL 73.7: Talk

Thursday, March 14, 2013, 11:00–11:15, H15

Electrostatic Doping in III-V Nanowire Tunnel FETs — •Thomas Grap and Joachim Knoch — Institute of Semiconductor Electronics RWTH University, D-52074 Aachen

Tunnel FETs (TFETs) have attracted a great deal of attention due to their potential superior off-state performance which would enable a substantial reduction in power consumption of highly integrated circuits. In order to improve the TFET performance, a nanowire (NW) device layout with ultrathin diameter and wrap-gate architecture with high-k gate dielectrics is proposed. Of special interest are III-V semiconductors, since they offer a low effective mass and a small band gap. As a result, in such a device structure electronic transport is one-dimensional (1D). Due to the particular band profile (p-i-n) excellent screening of the gate action on the source is mandatory in order to obtain a steep source-channel p-n junction. However a large doping concentration increases the Fermi-Level in source - due to a 1D transport and a low density of states of the III-V NW - limiting the inverse subthresholdslope of the TFET to 60mV/dec. As an alternative to the conventional doping, we successfully designed various device layouts using a triple-gate structure to electrostatically dope the NW. This allows us to adjust the screening and the Fermi-Level independently. We will show simulations performed for different TFET device geometries discussing the advantages of electrostatic doping over conventional doping with respect to the TFET performance. First experimental results on the proposed device layouts will be presented as well.