Catalytic Metal-Gated Nano-Sheet Field Effect Transistor and Nano-Sheet Tunnel Field Effect Transistor Based Hydrogen Gas Sensor- A Design Perspective

In this work, for the first time, the catalytic metal gate (CMG) based nanosheet Field Effect Transistor (NSFET) and nanosheet Tunnel Field Effect Transistor (NSTFET) are proposed for nano-scale device dimensions, and the different design aspects of catalytic metal gate (CMG)-based transduction for Hydrogen (H-2) sensing are extensively investigated using numerical device simulation. The influence of applied biasing conditions and structural parameter specifications on the sensing performance of CMG-NSFET and CMG-NSTFET are methodically analyzed from device electrostatics and carrier transport mechanisms. Furthermore, the relative maximum sensitivity variations with H-2-partial pressure, ambient temperature, and the presence of ambient Oxygen are comprehensively studied. The study reveals that compared to CMG-NSFET, the CMG-NSTFET demonstrates a high immunity against bias and doping variations, with a notably higher (> 50%) sensitivity within low H-2 partial pressures (10(-15) - 10(-10) Torr). Next, the sensing performance of CMG-NSTFET is systematically optimized through a band-gap and gate-stack engineering approach, leading to a 180% to 650% sensitivity improvement from lower (10(-15) Torr) to higher (10(-5) Torr) range of H-2 partial pressure. Finally, the performance of optimized CMG-NSFET and CMG-NSTFET are extensively benchmarked against other reported nanostructured CMG-FET and TFET-based H-2 gas sensors, exhibiting a notably higher sensitivity in the proposed sensors.