Simulation of Dual-Material Hetero-Double Gate Tunnel Field Effect Transistor (TFET) in Sub-Micron Region

Abstract

To meet the performance requirements of low power mobile devices, a device with a high ION/IOFF ratio at low-VDD is needed. TFETs are gaining popularity due to their low subthreshold slope and high transconductance compared to MOSFETs. However, silicon-based TFETs have low on-state current, which limits their use in high-performance applications. To overcome this limitation, using a narrower band gap material like Ge can increase tunneling efficiency at the source side. Additionally, the larger ambipolar current associated with Si-TFETs can be reduced by considering a dual-material hetero-double-gate-dielectric (DM HDG) TFET. The main objective of this research is to propose and characterize a new TFET structure by considering the advantages associated with hetero structure and hetero-gate-dielectric TFETs, which realizes a device with an enhanced ION and a suppressed ambipolar current. The structure was fabricated with the addition of a hetero-dielectric Buried Oxide (BOX) on the doped substrate for the reduction of ambipolar current. We will adopt source-to-gate overlap technique to achieve desired subthreshold slope (SS). All the simulations were done by using 2-D TCAD simulator by Atlas Silvaco. The structure was optimized in terms of (ION/IOFF) and other performance metrics and simulation results were compared with other available structures in the literature.

Keywords

• tfet
• leakage current
• transconductance
• simulation