Strain-Induced Performance Improvements in InAs Nanowire Tunnel FETs

This paper investigates the electrical performance improvements induced by appropriate strain conditions in n-type InAs nanowire tunnel FETs in the context of a systematic comparison with strained silicon MOSFETs. To this purpose, we exploited a 3-D simulator based on an eight-bandk pHamiltonian within the nonequilibrium Green function formalism. Our model accounts for arbitrary crystal orientations and describes the strain implicitly by a modification of the band structure. The effect of acoustic- and optical-phonon scattering is also accounted for in the self-consistent Born approximation. Our results show that appropriate strain conditions in n-type InAs tunnel FETs induce a remarkable enhancement of Ionwith a small degradation of the subthreshold slope, as well as large improvements in the Ioffversus Iontradeoff for low Ioffand VDDvalues. Hence, an important widening of the range of Ioffand VDDvalues where tunnel FETs can compete with strained silicon MOSFETs is obtained.