Effects of heavily doped source on the subthreshold characteristics of nanowire tunneling transistors

Abstract

In this abstract, we report on the effects of heavily doped source (impurity states) on the off-current and the inverse subthreshold slope of NW TFETs. The investigation is done for InSb NW TFETs. We show that even with α comparable with or greater than kT, there is still a significant reduction of the inverse subthreshold slope in TFETs from its ideal thermally-limited value in FETs. To investigate the effects of heavily doped source on the off-current and the inverse subthreshold slope of NW TFETs, we have developed a generalized full band quantum mechanical numerical model which is based on the non-equilibrium Green's function (NEGF) method within recursive Green's function (RGF) algorithm. The tunneling current in the presence of incoherent scattering is calculated and compared with the coherent scattering. In conclusion, we have developed a generalized full band quantum mechanical model to investigate the effects of heavily doped source on the subthreshold characteristics of NW TFETs. The method is applied to InSb NW TFETs. It is found that necessary heavy doping of the source is not a show-stopper for TFETs.