Design and Simulation of Dual-Metal-Gate Tunnel Field Effect Transistor with Biomolecule Sensing Applications.

To facilitate label-free detection of biomolecules, we propose a novel dielectrically modulated (DM) Dual-MetalGate Germanium Pocket based Tunnel Field Effect Transistor (DMG-GPTFET) with metallic drain (workfunction =3.9eV) biosensor. The utilization of germanium, having a relatively low bandgap, has enhanced the tunnelling phenomenon at the junction between source and channel. This enhancement eventually leads to an increase in the on current (ION). The proposed device employs dual cavities in the top and bottom gate oxides, which are being used to detect the biomolecules. This way the TFET becomes a biosensor and is tested for its ability to sense biomolecules based on their dielectric constant and charge density. The analysis is focused on evaluating the variations in energy band (E-B), electric field (E-F), surface potential (S-P) and transfer characteristics (I ds vs V GS ). It has been observed that as biomolecules get trapped in the nanocavity (k>1), the value of Ids increases, and the maximum value is attained in the order of $10^{-6}(\mathrm{A}/\mu$m) for k=10 at $\mathrm{V}_{\mathrm{GS}}=1$V and $\mathrm{V}_{\mathrm{DS}}=0.5V$