Influence of the Source Doping Concentration on the Subthreshold Swing (S) of Tunneling Field-Effect Transistors (TFETs)

Abstract

The subthreshold swing (S) of tunneling field-effect transistors (TFETs) has been modeled by using the Landauer formula, Wentzel-Kramers-Brillouin (WKB) approximation, Kane's two band k . p model and Fermi-Dirac statistics. From the proposed model, it has been observed that TFET characteristics are determined by the Fermi-Dirac distribution in the subthreshold region and by the tunneling probability in the saturation region. Thus, higher source doping concentration leads to higher on-current thanks to the increase of tunneling probability. However, at the same time, high source doping concentration can make TFETs suffer from the metal-oxide-semiconductor FET (MOSFET)-like constant S due to the tail of the Fermi-Dirac distribution. Based on our proposed model, the design guideline has been proposed to optimize the source doping concentration.