Drain Current Model of a Four-Gate Dielectric Modulated MOSFET for Application as a Biosensor

In this paper, an analytical model of a four-gate dielectric modulated MOSFET for label-free electrical detection of the biomolecules has been proposed. To provide a binding site for the biomolecules, the channel region of MOSFET is left open in the four-gate configuration, which is conventionally covered by the gate electrode. As a result, the electrical characteristics of the device are affected by the neutral and charged biomolecules that binds to the underlap (open) channel region. The electrostatics is developed by solving a 2-D Poisson's equation, assuming a parabolic potential profile along the channel direction using the conformal mapping technique and subsequently the drain current model is developed. The change in the threshold voltage is used as a sensing metric for the detection of biomolecules after their immobilization in the open region. The characteristic trends are supported and verified using the ATLAS device simulation software.