Analytical modeling of a split-gate dielectric modulated metal-oxide-semiconductor field-effect transistor for application as a biosensor

In this paper, an analytical model of a split-gate dielectric modulated Metal-oxide-semiconductor field-effect transistor (DM-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 result, the surface potential in this open area is affected by the neutral and charged biomolecules that binds to the underlap (open) channel. The solution of surface potential is obtained by solving a 2-D Poisson equation assuming parabolic potential profile along the channel direction using conformal mapping technique. The analytical model of threshold voltage is derived from the surface potential model and change in the threshold voltage is used as a sensing metric for detection of biomolecules after immobilization in the open region. The characteristics trends are supported and verified via “ATLAS” device simulation software.