Work function optimization for enhancement of sensitivity of dual-material (DM), double-gate (DG), junctionless MOSFET-based biosensor

Abstract

In this work, the impact of gate material work function on the sensitivity of dual-material, double-gate, junctionless MOSFET ( $$DMDG-JL-MOSFET$$ )-based biosensor has been studied. To enhance the sensitivity of the biosensor, optimization of gate work functions has been done through Sentaurus TCAD simulator. With the immobilization of biomolecules in the cavity at different value of work function of gate metal 1 (M1) and gate metal 2 (M2), i.e., WF1 and WF2, enhancement in sensing metrics (change in threshold voltage $$S_{V{\rm th}}$$ and $$I_{ON}$$ / $$I_{OFF}$$ ratio) is observed. The enhancement in sensitivity is profound in source-side gate (M1) work function (WF1) optimization as compared to drain-side gate (M2) work function (WF2) optimization. Sensitivity of 90 mV is observed in source-side gate work function optimization which is $$\sim$$ 89% more than the sensitivity of 23 mV which is achieved in drain-side gate work function optimization for a fixed concentration and dielectric constant of biomolecules. It has also been noted that the proposed structure exhibits $$\sim 90\%$$ higher sensitivity than the single-material, dual-gate, junctionless MOSFET ( $$SMDG-JL-MOSFET$$ ) biosensor. Results showcase that the optimization of gate metal work functions enhances the sensitivity of the biosensor.