A Fast and Stable Poisson-Schrödinger Solver for the Analysis of Carbon Nanotube Transistors

Carbon nanotube field-effect transistors have been studied in recent years as a potential alternative to CMOS devices because of their capability of ballistic transport. In order to account properly for ballistic transport we solve the coupled Poisson and Schrödinger equations for the analysis of these devices. Conventionally the coupled Schrödinger-Poisson equation is solved iteratively with appropriate numerical damping. Convergence problems of this coupled equation system are quite well known. We show that these problems occur due to inappropriate energy discretization for evaluating the carrier concentration. By using an adaptive integration method the simulation time is reduced and most of the simulations converge in a few iterations. Based on this approach we investigated the behavior of carbon nanotube field effect transistors.