(Invited) The Silicon Nanowire Accumulation-Mode MOSFETs

Abstract

The accumulation-mode MOSFET (AMOSFET) is a very simple structured FET configuration which offers the potential for fabricating low cost, high performance FETs on semiconductor nanostructures. The configuration consists of a single doping type silicon nanowire, ohmic source and drain contacts, and a partially gated region. Despite their simple structure, AMOSFETs are capable of showing excellent device characteristics. AMOSFETs fabricated on undoped VLS-grown silicon nanowires exhibit transfer characteristics, with ION/IOFF ratios ~105, and subthreshold swings as low as 150 mV/dev. However, contrary to expectations, AMOSFETs fabricated on intentionally p-type doped silicon nanowires exhibit very poor transfer characteristics; this we attribute to a decrease in conductivity of the doped silicon nanowire upon oxidation. A new device structure, called the AMISFET is demonstrated, which overcomes the problems associated with oxidation of doped nanowires, and is capable of exhibiting good transfer characteristics for FETs fabricated on doped nanowires.