Physics-Driven Performance Exploration of a Nano-Engineered Dielectric Modulated Cylindrical BioFET

Abstract

This paper comprehensively investigates a compact, nano-engineered and short-channel symmetrically doped Cylindrical MOSFET with an I-shaped oxide layer-based biosensor (SCSD-CY-BioFET) for generic label-free detection of biomolecules. For analyzing the biosensing performance, peak transconductance sensitivity and peak output conductance sensitivity has been presented along with other sensitivity metrics to test reliability and sensitivity of SCSD-CY-BioFET. Present work employs symmetric doping with highly doped source and drain extensions, enhancing carrier injection, drive current, and electrostatic balance. The sensing capability has been assessed by varying primary parameters like ambient temperature, length, and thickness of cavity. For neutral biomolecules, the percentage sensitivity (relative change) varies from 169.85% (206.382 mV) to 244.22% (296.755 mV) when dielectric constant (K) of biomolecule changes from 3 - 10 (considering threshold voltage as metric of biosensing). Similarly, for charged biomolecules, the percentage sensitivity (relative change) varies from 379.91% (461.623 mV) to 16.8% (101.096 mV) when the charge density (N f ) of biomolecule changes from -10 12 /cm 2 — +10 12 /cm 2 (considering threshold voltage as metric of biosensing). Compared to the dual sided cavity, source-ended cavity has shown better sensing characteristics than the drain-ended cavity, with an improvement of 0.1 µA (0.1 pA) in on-current (off-current) sensitivity.