A novel dual-gate negative capacitance TFET for highly sensitive label free biosensing

The negative capacitance (NC) tunnel FET (NCTFET) emerges as a viable choice for the development of highly sensitive biosensors. A dual-gate (DG) structure and n+ doped pocket within the NCTFET is introduced in this study to boost biosensor performance and sensitivity. This research offers a comprehensive and comparative analysis of two biosensor designs: the DG-NCTFET and the n+ pocket-doped DG-NCTFET. Both biosensors feature nanogaps on either side of the fixed dielectric, augmenting their biomolecule capture areas. Sensitivity assessments are conducted considering charged and neutral biomolecules with a range of dielectric constants (k). The n+ pocket DG-NCTFET exhibits an I_ON sensitivity roughly 20 times greater than that of the sensor without a pocket (3.5 × 10⁶ for n+ pocket DG-NCTFET and 1.8 × 10⁵ for DG-NCTFET), primarily because it conducts current in both vertical and lateral directions. Furthermore, for fully filled nanocavity with neutral biomolecules, the maximum I_ON/I_OFF sensitivities attained are 1.2 × 10⁵ and 2.8 × 10⁴ for the n+ pocket DG-NCTFET and conventional DG-NCTFET, respectively. Moreover, this research delves into the impact of steric hindrance and the irregular placement of probes, aiming to grasp the non-ideal traits exhibited by the sensors. Significantly, sensitivity experiences a minimal increase of approximately 6%–11% when the fill factor escalates from 40% to 66%. In order to set a standard of comparison, the proposed biosensors are benchmarked against existing literature in terms of sensitivity, affirming their efficacy. The findings indicate that the proposed biosensors represent a promising alternative for detecting a wide range of both charged and neutral biomolecules.