Dielectric/charge density modulated junctionless FET based label-free biosensor

In this research article, a junctionless FET is reported to be deployed as a biosensor for the label-free electrical detection of biomolecules with the help of modulation of dielectric constant and modulation of charge density. As structurally JLFET is a singly doped device it does not has any doping gradient or junction. Hence, it abolishes the need for complex processing steps to create ultra-steep doping profiles with very high doping concentrations gradient and other lithography related challenges. This makes the fabrication easier as well as cost effective. The immobilization of biomolecules controls the device surface potential according to the biomolecules' dielectric constant and charge density and controls the device performance parameters in accordance. These changes in device performance parameters are calibrated to detect the different biomolecules. There are double cavities of 80 nm each to immobilize the biomolecule and the cavities are 3 nm thick making it suitable for detecting larger sized biomolecules and polymers. The effect of biomolecules dielectric constant modulation and charge density modulation has been studied and the sensitivity of the device has been analyzed in terms of Delta ION,Delta VTH,Delta gm, and Delta SS.