Analytical Drain Current Modeling of Double-Gate Tunnel Field-Effect Transistors

In this paper, we present an analytical model for the drain current of a double-gate tunnel field-effect transistor (DGTFET), derived using the pseudo-2-D Poisson's equation in order to obtain the surface potential in both the channel and the source regions. We have proposed a new model for the surface potential when the channel is under accumulation, and have analytically modeled source depletion as well. We have also proposed a modification in the existing model for the band-to-band tunneling, by taking into account the change in the carrier momentum vector during its transit from the source valence band to the channel conduction band. Another important contribution of our work is the prediction of zero drain current at zero drain bias, which is physically modeled for the first time. The negative conductance region for low gate bias is also modeled for the first time using an empirical formulation, without using any fitting parameter. Extensive TCAD simulations were performed in order to prove the veracity of our model with respect to drain bias, gate bias, substrate doping, and metal work function, and the match of our model results with the simulated data was found to be excellent.