Comparative Analysis of Underlapped Silicon on Insulator and Underlapped Silicon on Nothing Dielectric and Charge Modulated FET based Biosensors

A biosensor based on silicon on insulator (SOI) MOSFET provides many advantages over the conventional biosensors but still suffers from the inherent problem which exists in SOI structures. Silicon on nothing (SON) MOSFET which is a derivative of SOI MOSFET is an option which has been considered by many as an alternative due to its excellent performances. In this study, underlapped silicon on insulator (USOI) and underlapped silicon on nothing (USON) dielectric and charge modulated FET (DCMFET) has been compared for biosensing application. Modulation of the devices electrical characteristics, namely surface potential, threshold voltage, and sensitivity have been studied to understand the sensing of biomolecules without labeling. Detection of biomolecules is evaluated as a shift of threshold voltage of the devices with the change in biomolecules dielectric constants and charges. The data obtained from the analytical models showed both the devices as highly sensitive; however, USON-DCMFET is found to be the better choice. The analytical models have also been verified by using the data obtained from the 2-D numerical simulations performed using SILVACO ATLAS.