High Sensitivity Dielectric-Modulated Negative Capacitance Gate-All-Around TFET (DM-NC-GAA-TFET) Biosensor with Nanocavity for Label-Free Biomolecule Detection

This study presents a high-performance dielectric-modulated Negative Capacitance Gate-All-Around Tunnel Field-Effect Transistor (DM-NC-GAA-TFET) biosensor for label-free biomolecule detection. The proposed device employs a nanocavity structure with varying dielectric constants (K) of biomolecules to improve sensing performance through enhanced gate-to-channel coupling and electrostatic control. The electrical and sensing characteristics of the biosensor are analyzed for different dielectric constants and cavity lengths. The transfer characteristics exhibit excellent switching behavior with an ON-state current of approximately 6.2 × 10−6 A and an OFF-state current of nearly 10−14 A, resulting in a high ION/IOFF ratio. The output characteristics demonstrate stable current saturation and improved channel controllability, while the transconductance reaches approximately 13.5 × 10−6 S, indicating efficient carrier transport. The effect of dielectric modulation is investigated for dielectric constants ranging from 1 to 10. The drain current increases from 5.8 × 10−6 to 6.7 × 10−6 A with increasing dielectric constant, confirming enhanced sensing capability. The proposed biosensor achieves a maximum drain current sensitivity of 8.1 × 10−7 A at K = 10. Furthermore, the subthreshold swing improves from 0.066 to 0.049 V/dec, while drain induced barrier lowering (DIBL) decreases from 0.038 to 0.021. The threshold voltage sensitivity increases from 0.085 to 0.148 for a 25 nm cavity length. These results demonstrate that the proposed DM-NC-GAA-TFET biosensor provides high sensitivity, excellent switching performance, and improved electrostatic characteristics for future low-power biosensing applications.