EMA-based modeling of the surface potential and drain current of dual-material gate-all-around TFETs

An analytical model for the surface potential and drain current of dual-material gate-all-around tunnel field-effect transistors based on evanescent mode analysis (EMA) is introduced. In the EMA, the channel potential is a sum of the solutions of the one-dimensional (1D) Poisson equation and two-dimensional (2D) Laplace equation. The EMA is preferred over the parabolic approximation due to the invariance of the characteristic length (lambda) over the channel. The band-to-band tunneling rate is integrated over the tunneling volume to calculate the drain current. The accuracy of the model is evaluated by comparing it with results obtained from numerical simulations, revealing good agreement. The presented model could be easily integrated into commercial circuit simulators because of its accuracy and simplicity.