Electrical Characterization by Counter-Doped Pocket Design in Tunnel FETs

Abstract

The effects of low net-doped region on the electrical performance of tunnel field-effect transistors (TFETs) are investigated using TCAD simulation. Compared with previous studies, it is observed that the low net-doped region between the source and pocket can enhance TFET electrical characteristics such as on-current (Ion) and subthreshold swing (SS) with fine on-off current ratio (Ion/Ioff). By optimizing the length of the low net-doped region, Ion increased 14.6 times and the SS is reduced by 34.6 % compared with the TFET where the low net-doped region was not considered. Furthermore, guidelines for designing counterdoped pocket are proposed considering the low net-doped region. The local minimum in the conduction band can be used to further improve the on-current and SS performance by adjusting the pocket width and doping concentration. To avoid pocket-induced SS degradation, the pocket doping concentration must also be taken into account when determining the optimal value of the pocket width and vice versa.INDEX TERMS Tunnel field-effect transistor (TFET), counter-doped pocket, low net-doped region, pocket width, tunneling width