Performance Analysis of Heterojunction DMDG-TFET with Different Source Materials for Analog Application

摘要

This work investigates the efficacy of the source material of a Dual Material-Double Gate-Tunnel FET (DMDG-TFET). In this respect, the analog performance of the device such as subthreshold swing (SS), subthreshold voltage (V_th), current switching ratio (I_ON/I_OFF) and drain current (Ids) is examined for different source materials. The choice of the material is made in such a way to study the effect of both the elemental semiconductors of 14th group and also the compounds from the 14th group of the periodic table. A comparative study of DMDG-TFET for different mole fraction of Strained Silicon (Si_1-xGe_x) is done in the source region and the optimum value of mole fraction is used for further analysis. Further, different source region materials used are Silicon (Si), Germanium (Ge) and Strained Silicon (Si_0.5Ge_0.5) forming a hetero-junction that gives superior band bending on application of gate bias. Subsequently, the electrical and analog parameters of all the three devices are also assessed. The simulation is done using Non-local Band-to-Band Tunneling (BTBT) Model using SILVACO TCAD. It is found that Ge and Si_0.5Ge_0.5 outperform the basic Si source device, Ge shows the highest driving but Si_0.5Ge_0.5 is assessed to be the best source region, material out of all the three materials, in most of the electrical and analog parameters.