Analog Circuits Using Double-Gate Multilayer MoS2 Field-Effect Transistor for Sensor Applications

The advantages of novel double-gate (DG) multilayer MoS
₂
transistors for analog circuit applications are presented. Such components are shown to be especially useful in signal-conditioning circuits in sensor instrumentation systems. The nearly symmetric DG device architecture can be exploited in the design of analog front-end circuits to mitigate the effect of flicker (1/
${f}$
) noise. Quantum mechanical calculations validated by comparisons with experimental data indicate that with active semiconductor layer thickness >2 monolayers (MLs), the sheet carrier density per gate is increased relative to single gate field-effect transistors (FETs) resulting in a lower noise figure. Calculated normalized noise spectral power densities for the single and DG thin-film transistors (TFTs) at the same gate bias clearly show that the DG devices have lower noise than the single gate devices. In sensors for low-frequency signals such as bio-signals, DG transistors allow convenient direct coupling of the signal through one gate, with the other gate available for mixing with a high-frequency signal and/or applying bias voltages without requiring large capacitors. Such circuits are well-suited for use with silicon CMOS technology using back-end-of-the-line (BEOL) fabrication methods.