Bandgap modulated phosphorene based gate drain underlap double-gate TFET

Abstract

In this work, a novel bandgap modulated gate drain underlap (BM-GDU) structure of tunnel-FET exhibiting suppressed ambipolar characteristics and steep SS is proposed by applying layer dependent bandgap and electron affinity property of 2-D material Phosphorene. An artificial hetero-junction between the source and channel region is composed of trilayer and bi-layer Phosphorene respectively without any lattice mismatch. BM-GDU TFET exhibits ON-current ∼100 μA/μm, on-off ratio greater than 109 and average subthreshold swing 28.6 mV/decade for a channel length of 20 nm at VDD of 0.4 V due to its low bandgap at source region than the channel region, larger tunneling window and lower carrier effective mass. Gate drain underlap structure yields ∼10 decades ambipolar suppression than conventional homojunction DG TFET. Performance parameters of our BM-GDU TFET by varying channel length are also studied using our developed self-consistent quantum mechanical transport simulator.