Analytical Modeling of Charge Plasma-Based Optimized Nanogap Embedded Surrounding Gate MOSFET for Label-Free Biosensing

Abstract

In this paper, analytical modeling of a charge plasma-based nanogap embedded surrounding gate MOSFET biosensor for label-free biosensing has been presented and verified with extensive simulated device data. Along the channel, considering parabolic potential profile, surface potential,threshold voltage,and drain currents have been modeled. Sensitivity has been analyzed by measuring the shift in I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> /I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OFF</sub> and threshold voltage when the biosensor interacts with the neutral or charged biomolecules. Less thermal budgeting scheme with simplified fabrication process flow, i.e., no ion implantation or diffusion can be achieved easily here due to new charge plasma concept. In addition, the issues related to the doping control and random dopant fluctuations have been reduced significantly to make the device immune to the process variation. Hence, the proposed device has been optimized for the enhancement in device electrostatics and sensitivity. Extensive TCAD simulations have been performed to investigate the device parameters and to verify the model data. Hence, the proposed model can be considered as an optimal model of a biosensor for the future reference.