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 a 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 the on-current ( $I_{\mathrm {on}}$ ) and subthreshold swing (SS) with fine on-off current ratio ( $I_{\mathrm {on}}/I_{\mathrm {off}})$ . By optimizing the length of the low net-doped region, $I_{\mathrm {on}}$ increased 14.6 times and SS is reduced by 34.6 % compared with the TFET where the low net-doped region was not considered. Furthermore, guidelines for designing counter-doped 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 considered when determining the optimal value of the pocket width and vice versa.

Keywords

• Tunnel field-effect transistor (TFET)
• counter-doped pocket
• low net-doped region
• pocket width
• tunneling width