Potential and Drain Current Modeling of Gate-All-Around Tunnel FETs Considering the Junctions Depletion Regions and the Channel Mobile Charge Carriers

In this paper, we present an accurate analytical potential model for the homojunction cylindrical gate-all-around (GAA) tunnel FET (TFET) by solving Poisson's equation with appropriate boundary conditions in the cylindrical coordinates. Taking the mobile charge carriers in the channel and the depletion regions inside the source and drain into account, the model predicts the electrostatic potential of the device in all the regions of the device operation more accurately, compared with the predictions of the previously reported ones. The potential model is utilized for developing some relations for calculating important quantities in TFETs, such as lateral electric field, minimum tunneling length, and the drain current. Owing to the physical and analytical nature of the developed relations, one can pursue the influence of the transistor parameters on the electrical characteristics of GAA TFETs. To assess the accuracy of the proposed models, the results of them are compared with those of the numerical simulations and found to be accurately predicting the simulation results for different device parameters.