Variability Effects in Nanowire and Macaroni MOSFETs—Part I: Random Dopant Fluctuations

In this article and the related Part II, we investigate variability effects on the threshold voltage of nanowire and Macaroni MOSFETs, focusing on random dopant fluctuations (RDFs) and random telegraph noise, to assess their dependences on device radius, channel length, and doping. In Part I, we address threshold voltage fluctuations induced by RDF and show that different trends emerge with respect to planar devices, being dependent on whether the conduction is bulk- or surface-dominated. Macaroni devices with thin silicon regions can improve RDF, while moving from inversion- to accumulation-mode devices results in a worsening of this parameter.