Gate electrode stacked source/drain SON trench MOSFET for biosensing application

Abstract

This work inspects a dielectrically modulated (DM) stacked source/drain SiGe dual-metal trench gate silicon on nothing (SON) metal–oxide–semiconductor field-effect transistor (SiGe-DMTG SON MOSFET) biosensor to enhance the sensing capability of the device. A nano-cavity is implanted in the either side of gate area for immobilization of biomolecules which can modulate the gate capacitance and dielectric constant of the nanocavity area. Thus the device undergoes a threshold voltage shift which has a great impact on device sensitivity. So SiGe-DMTG SON MOSFET biosensor is proposed to identify the sensing performance of various analytes like Uricase (k = 1.54), Streptavidin (k = 2.1), Biotin (k = 2.63), 3-aminopropyltriethoxysilane (APTES) (k = 3.57) and protein (k = 8) using DM technique. The electrostatic properties of the neutral biomolecules such as electrostatic potential, electric field, On current, switching ratio, threshold voltage, On current sensitivity, threshold voltage sensitivity, and subthreshold performance of SiGe-DMTG SON MOSFET biosensor have been evaluated using 2D ATLAS device simulator. Further, the parasitic capacitances of the proposed biosensor has been investigated for different biomolecules in the nano-cavity region in order to observe the sensing performance of the device. From the result analysis it has been observed that for protein (k = 8), the proposed SiGe-DMTG SON MOSFET biosensor offers a threshold voltage sensitivity of 0.581 and On current sensitivity of 1.765. Apart from this, protein (k = 8) offers a strong threshold voltage shift of 104.8 mV with respect to k = 1 shows best suited for biosensing application.