A modified pseudo 2D physically-based model for double-gate TFETs: Role of precise calculations of drain and source depletion regions

Abstract

In this current study, a modified pseudo two-dimensional (2-D) semi-analytical model for double gate tunnel FETs (DG-TFETs) is introduced. The main regions in the DG-TFET structure are the channel and the depletion regions inside the source and the drain. In such regions, the 2-D Poisson's equation is solved by adjusting suitable boundary conditions. The source and the drain depletion region lengths are calculated precisely by an iterative technique resulting in an accurate prediction of the electrostatic potential. According to the obtained 2-D electrostatic potential, the energy band diagram could be extracted and, consequently, the minimum tunneling width is calculated. Accordingly, the model of drain current is introduced by applying Kane's tunneling model. Further, the source depletion charge and the channel charge are derived, and the terminal capacitance components are then extracted. A comparison between the proposed model and SILVACO TCAD simulations shows a satisfactory agreement that confirms the validation of the presented model robustness.

Keywords

• DG-TFET
• Depletion regions
• Tunneling width
• Poisson's equation
• Surface potential