【Device Papers】Unveiling design and optimization of β-Ga₂O₃ FinFET for high sensitivity and reliable ammonia gas detection

      Researchers from University of Delhi have published a dissertation titled " Unveiling design and optimization of β-Ga₂O₃ FinFET for high sensitivity and reliable ammonia gas detection " in Journal of Physics D: Applied Physics.

Abstract

      This study investigates the ammonia (NH₃) sensing performance capability of a beta gallium oxide (β-Ga₂O₃) fin field-effect transistor (FinFET) using cobalt (Co) as the sensing gate electrode. The high thermal and chemical stability of β-Ga₂O₃, integrated with the superior electrostatic control of the FinFET architecture, enables enhanced sensitivity and reliable operation, even in harsh environments. The design and extensive simulations of the proposed device have been carried out using the Sentaurus TCAD simulator. Furthermore, to validate the accuracy of the simulation models, the β-Ga₂O₃ FinFET was well-calibrated with the experimental results. The detection of NH₃ is facilitated through measurable variations of key electrical parameters such as the surface potential, transfer characteristics, threshold voltage and transconductance. The sensitivity of the proposed sensor at different concentrations of NH₃ is derived from the I_DS–V_GS curve in terms of the drain OFF current（S_IDOFF），ON current (S_IDON)，threshold voltage (S_VTH) and switching ratio (S_IDON/IDOFF). The simulation results reveal that the β-Ga₂O₃ FinFET NH₃ sensor exhibits an exceptional SIDOFF of 5.94 × 10⁴ and SIDON/DOFF of 2.85 × 10⁴ for a 10 ppm concentration of ammonia at room temperature. A linear sensing response over varying concentrations of NH₃ demonstrates the sensor’s robustness and effectiveness for precise monitoring of NH₃. Furthermore, in order to optimize the sensitivity of the proposed sensor, the impact of the variation of fin dimensional parameters, such as fin width and fin height, has been thoroughly examined. The optimally designed β-Ga₂O₃ FinFET NH₃ sensor illustrates a low detection limit of 0.37 ppm with a fast transient response and recovery times of 30 μs and 62 μs, respectively. In addition, the reliability of the sensor was also tested over a broad temperature range (275 K–425 K). Finally, a detailed comparative analysis with existing NH₃ gas sensors proved that the proposed sensor offers enhanced sensitivity, a rapid dynamic response and a low detection limit, making it a potential contender for designing ammonia sensors.

DOI：

https://doi.org/10.1088/1361-6463/ae93cd