A Study on the Performance of Gate-All-Around Heterojunction Tunnel Field-Effect Transistors Based on Polarization Effect

Tunnel field-effect transistors (TFETs) have gained prominence in low-power applications for their capability to surpass the subthreshold swing limit of 60 mV/decade. This paper introduces a TFET, named gate-all-around polar-TFET (GAA-P-TFET), which leverages the polarization effect at the interface of In0.75Ga0.25N/Al0.1In0.9N heterojunctions to enhance TFET performance, particularly to reduce the average subthreshold swing (SS¯) and increase the ON-OFF current ratio (ION/IOFF). The TCAD simulation results demonstrate that incorporating an Al0.1In0.9N layer between the source and channel regions notably improves the performance of the GAA-P-TFET compared to the conventional GAA-TFET. At a drain-source voltage (VDS) of 0.5 V, the SS¯ for the GAA-P-TFET reaches a minimum of 8.1 mV/decade within a current change spanning 9 orders of magnitude. Simultaneously, the ION/IOFF can attain a maximum value of 1012. Furthermore, this study analyzes the impact of various parameters on device performance. The results show that the average subthreshold swing (SS¯) decreases with decreasing channel/drain doping concentration and gate dielectric layer thickness. Moreover, the ON-state current notably rises with an increase in device diameter and source doping concentration.