A sub k_BT/q semimetal nanowire field effect transistor

The key challenge for nanoelectronics technologies is to identify the designs that work on molecular length scales, provide reduced power consumption relative to classical field effect transistors (FETs), and that can be readily integrated at low cost. To this end, a FET is introduced that relies on the quantum effects arising for semimetals patterned with critical dimensions below 5 nm, that intrinsically has lower power requirements due to its better than a "Boltzmann tyranny" limited subthreshold swing (SS) relative to classical field effect devices, eliminates the need to form heterojunctions, and mitigates against the requirement for abrupt doping profiles in the formation of nanowire tunnel FETs. This is achieved through using a nanowire comprised of a single semimetal material while providing the equivalent of a heterojunction structure based on shape engineering to avail of the quantum confinement induced semimetal-to-semiconductor transition. Ab initio calculations combined with a non-equilibrium Green's function formalism for charge transport reveals tunneling behavior in the OFF state and a resonant conduction mechanism for the ON state. A common limitation to tunnel FET (TFET) designs is related to a low current in the ON state. A discussion relating to the semimetal FET design to overcome this limitation while providing less than 60 meV/dec SS at room temperature is provided.