An analytical drain current model of Germanium source vertical tunnel field effect transistor

Abstract

This paper presents an analytical modeling of the drain current for a Germanium source vertical tunnel field effect transistor. Both one dimensional (1D) and two dimensional (2D) Poisson's equation are used for solving the potential distribution as the device structure possess both vertical and lateral band-to-band tunneling components. The 2D band-to-band tunneling model is employed for solving the lateral tunneling while the 1D band-to-band tunneling model is implemented on solving the vertical tunneling which consist of the source region and the overlap channel region. The length of the maximum and minimum tunneling widths are calculated by measuring the distance from the edge of the valence band to conduction band of the energy band profile. Kane's band-to-band tunneling generation rate is used to model the drain current by superimposing two current components. In addition, the impact of bandgap narrowing as well as quantum correction on the drain current are also factored into the model. The analytical models are checked and matched against the results obtained from the TCAD simulations to ensure its accuracy.