Direct Source-to-Drain Tunneling Current in Ultra-Short Channel DG MOSFETs by Wavelet Transform

In this work, a new approach to determine the effect of direct source-to-drain tunneling (DSDT) on 2-D double-gate (DG) MOSFETs is presented. The tunneling probability of electrons with different energy levels and tunneling distances through the potential barrier is calculated using harmonic wavelets and the results are compared to those calculated with the Wentzel-Kramers-Brillouin (WKB) method. Next, by having the tunneling probability the DSDT current is calculated and compared to TCAD simulations data, which are based on WKB model, and also to NanoMOS, a Non-Equilibrium Green's Function (NEGF) 2-D simulator for DG devices. The difference between these methods and their impacts on the resulted DSDT as well as the subthreshold behavior are investigated. Furthermore, a first step towards compact modeling is made by approximating the tunneling current density.