GaSb/GaAs Type-II Heterojunction TFET on SELBOX Substrate for Dielectric Modulated Label-Free Biosensing Application

A novel GaSb/GaAs type-II heterojunction TFET on SELBOX substrate (HJ-STFET)-based dielectric-modulated ultrasensitive label-free biosensor has been demonstrated in this article. The SELBOX substrate has been used in the proposed TFET-based sensor to reduce the lattice heat and improve the ${I}_{\mathrm {ON}}/{I}_{{\mathrm {OFF}}}$ ratio. Cavities in the gate oxide of the TFET are created to form dual-cavity (DC) HJ-STFET structure. These cavities contain the biomolecules to be sensed through the principle of gate-dielectric modulation. To validate the results, the analytical modeling of surface potential has been compared to simulated outcomes for different dielectric constant values of biomolecules. The threshold voltage sensitivity ( ${S}_{VT}$ ) and ${I}_{\mathrm{ON}}/{I}_{\mathrm{OFF}}$ sensitivity parameters of the proposed DC-HJ-STFET structure have been thoroughly investigated considering different biomolecules. The proposed DC-HJ-TFET structure is shown to have a higher current sensitivity ( $\sim 6.67\times10$ ¹¹ ) and threshold voltage sensitivity (0.37 V) values over some recently reported TFET-based biosensors. Finally, we have verified the drain and back gate biasing, as well as linearity fit verification, on the proposed biosensor’s performance.