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-band k p Hamiltonian 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 I_on with a small degradation of the subthreshold slope, as well as large improvements in the I_off versus I_on tradeoff for low I_off and V_DD values. Hence, an important widening of the range of I_off and V_DD values where tunnel FETs can compete with strained silicon MOSFETs is obtained.