Analytical Modelling of Symmetric Gate Underlap Quadruple Gate Multichannel Junctionless MOSFET Biosensor

In this work, we have proposed a quadruple gate multi-channel junctionless MOSFET structure that acts as a label-free biosensor to identify neutral and charged biomolecules by dielectric modulation procedure. The device has been analytically modelled through the solution of two dimensional Poisson’s equation using conformal mapping to account for the fringing fields. As various bio targets are immobilized inside the cavity on a thin adhesive silicon dioxide film, the device electric properties such as the surface potential, drain current, threshold voltage change differently. The threshold voltage shift has primarily been utilised as the sensing parameter for the detection and identification of a specific biomolecule. The biosensing characteristics have been discussed by varying the dielectric constant and charge of biomolecules with analysing non-ideal issues like temperature variation and steric hindrance. A DNA-based variability study has also been done with real-time analysis. All the results obtained from the analytical model have been validated against SILVACO TCAD simulation data to substantiate our developed model. The structure exhibits near ideal subthreshold slope and low threshold voltage roll-off even at sub − 20 nm regime and high, reliable sensitivity for a wide range of bio-targets suggesting the possible application in short channel biosensor regime.