A proof of concept for reliability aware analysis of junctionless negative capacitance FinFET-based hydrogen sensor

This work demonstrates the reliability-aware analysis of the Junctionless negative capacitance (NC) FinFET employed as a hydrogen (H₂) gas sensor. Gate stacking of the ferroelectric (FE) layer induces internal voltage amplification owing to the NC property, thus, improving the sensitivity of the baseline junctionless FinFET. A well-calibrated TCAD model is used to investigate the sensing characteristics of the proposed FinFET-based H₂ sensor by employing the palladium (Pd) metallic gate as a sensing element. The mechanism involves the transduction of H₂ gas molecules over the metal gate; due to the diffusion process, some atomic hydrogen diffuses into the metal. The H₂ gas absorption at the metal surface causes a dipole layer formation at the gate and oxide interface, which changes the metal gate work function. As a result, this change in the work function can be used as a sensing parameter of the proposed gas sensor. Further, the threshold voltage and other electrical characteristics, such as output conductance, transconductance, and drain current are examined for sensitivity analysis for both NC and without NC JL FinFET at different pressure ranges, keeping the temperature constant (i.e. 300 K). The device variation, i.e. Fin thickness, Fin height, doping and thickness of HfO₂ ferroelectric layer, etc, on sensor sensitivity has been evaluated through extensive simulation. This paper also presents a detailed investigation of the sensor’s reliability in terms of work function variation, random dopant fluctuation, trap charges, and device aging, i.e. end of a lifetime. At last, the acquired results are compared with earlier reported data, which justifies the profound significance of the proposed junctionless negative capacitance FinFET-based H₂ gas sensor.