N+ Pocket-Doped Vertical TFET for Enhanced Sensitivity in Biosensing Applications: Modeling and Simulation

This article examines the performance of N+ pocket-doped vertical tunnel field-effect transistor (VTFET)-based label-free biosensors with the help of an analytical model developed for electrostatic potential, electric field, and drain current along with an extensive verification of the simulated device data. The model incorporates the effects of dielectric constant as well as charge and renders a generalized solution applicable for both neutral and charged biomolecules. Besides, the sensitivity has been analyzed by measuring the shift in drain current due to a change in the dielectric constant. It has been observed that the proposed sensor shows a large deviation in drain current, and hence, ION can be used as an appropriate sensing parameter. The variations in the drain current and threshold voltage (V
_th
) due to the impact of positive/negative-charged biomolecules have also been studied. Extensive TCAD simulations have been performed to investigate the device performance when the nanogaps are fully filled, three-quarterly filled, half-filled, quarterly filled, and unequally filled. Furthermore, a comparison has been made with MOSFET-based biosensors.