In this paper a new structure of carbon nanotube field-effect transistors (CNTFETs), with stepwise doping lightly doped drain and source regions (Stepwise LDDS-CNTFET) is presented. Simulations have been done by the self-consistent solution of 2-D Poisson–Schrodinger equations, within the nonequilibrium Green’s function (NEGF) formalism. Simulation results show that by proper selection of stepwise doping in stepwise LDDS structure a larger ON–OFF ratio, a smaller OFF current, a lower dissipated power and also a lower subthreshold swing, a lower drain induced barrier lowering, can be obtained in comparison with conventional and other similar structures.
