Investigation on palladium gate electrode-based SOI junctionless FET for hydrogen gas sensing

This study provides a comprehensive investigation on palladium (Pd) gate electrode-based silicon on insulator (SOI) junctionless field-effect transistor (JLFET) for hydrogen gas (H₂) sensing (Pd–SOI-JLFET). The device has a gate dielectric stack consisting of silicon dioxide (SiO₂) and hafnium dioxide (HfO₂). An extensive analysis was conducted to detect and identify the presence of hydrogen gas by examining several electrical characteristics such as drain current (I_DS), transconductance (g_m), output conductance (g_d), energy band diagram (E), gate-to-source capacitance (C_GS), and surface potential (Φ_s). Furthermore, a comprehensive investigation was conducted to examine the impact of the presence of H₂ gas and variations in temperature on important parameters associated with the short channel effects (SCEs) including off-state current (I_OFF), on-state current (I_ON), subthreshold swing (SS) and threshold voltage (V_th). In addition, the sensitivity analysis of the off-state current (I_OFF) by considering process variation effect has been done. Sensitivity is also calculated at various temperatures for the detection of hydrogen gas molecule. At the temperature of 300K, the sensitivity values were obtained as 1.50083, 3.21754, 27.71483, 152.39617 and 2052.8 for pressure values 10⁻¹⁴ Torr, 10⁻¹³ Torr, 10⁻¹² Torr, 10⁻¹¹ Torr and 10⁻¹⁰ Torr, respectively. This analysis provides a thorough examination of the performance and efficacy of the Pd–SOI-JLFET hydrogen gas sensor highlighting its potential for a wide range of hydrogen sensing applications.