Physics-based surface potential, electric field and drain current model of a p+ Si1-xGex gate-drain underlap nanoscale n-TFET

This article develops a 2-D model for surface potential, electric field and drain current for a nanoscale silicon tunnel field effect transistors (TFET) with a delta p(+)Si(1-x)Ge(x) layer at source-channel tunnel junction. Mathematical formulation based on the TFET physics has been carried out throughout the text taking into consideration the various parameters involving the mole-fraction-dependent Si1-xGex layer. Both lateral and vertical electric fields have been modelled. A comparison is conducted between the modelled and the simulated values for three cases: polysilicon gate with silicon dioxide as gate dielectric, aluminium gate with alumina as gate dielectric and aluminium gate with hafnium oxide as gate dielectric. The model is found to be valid for all the three cases.