Ultralow-power dielectric-modulated nanogap-embedded sub-20-nm TGRC-MOSFET for biosensing applications

This work examines a transparent gate recessed channel (TGRC) metal-oxide-semiconductor field-effect transistor (MOSFET) for biosensing, including a nanogap cavity for detection of biomolecules and a transparent gate to enhance the overall current efficiency of the RC-MOSFET. For the detection of neutral biomolecules, electrical characteristics such as ION/IOFF, shift in threshold voltage and change in surface potential have been studied and thereafter, sensitivity of has been evaluated. The biosensor showed enhanced sensitivity for biomolecules with increase in their dielectric value, due to greater on-current owing to the change in capacitances. The capacitances were therefore also evaluated. In addition, immobilization of biomolecules degrades the noise immunity of MOSFET and thereby their overall biosensing performance, while the noise immunity of the TGRC device was very high even in the presence of biomolecules. Furthermore, modulation of the cavity gap length was also investigated, revealing that its increase (from 8 to 20 nm) significantly enhanced the sensitivity of the proposed biosensor. Overall, the results of this analysis reveal that such TGRC-MOSFET biosensors can exhibit high sensitivity (1.45) at very low drain bias (0.2 V), enabling their use for biosensor applications to diagnose various diseases which require lower noise, high speed, low power, and high density.