Junctionfree Gate Stacked Vertical TFET Hydrogen Sensor at Room Temperature

Presented through this work is an investigation of junctionfree gate-stacked (SiO2 + high-k) double gated vertical tunnel field-effect transistor (JF-GS-VTFET) with focus on its hydrogen (H-2) sensing performance at room temperature (RT) for the first time. JF-GS-VTFET with vertically characterized channel length feature minimizes short channel effects (SCEs), elevates gate controllability over regular TFETs without the presence of any sharp doping gradient. A systematical study of the sensing performance is demonstrated through effective variations in Palladium (Pd) and Gold (Au) catalytic metal gate work functions corresponding to the concentration of hydrogen appearing at the gate metal surface. A concentration dependent thorough analysis has been illustrated in terms of energy band, potential, transfer and transient characteristics. Sensing capability of the device have been analyzed in terms of variations in detecting parameters such as transconductance (g(m)), off current, on current, threshold voltage and sub-threshold slope in presence of the target gas using SILVACO ATLAS TCAD. At 1.04 ppm H-2 gas concentration, the optimally designed sensor exhibits high I-ON /I (OFF) ratios in the order of similar to 10(13) and similar to 10(11), high g m sensing responses of 99.98% and 98.93%, high off current sensing responses of similar to 1.895 x 10(4) and similar to 1.47 x 10(4), better sub-threshold swing sensing responses of similar to 0.71 and similar to 0.55, increased threshold voltage sensing responses of similar to 0.27 and similar to 0.25 for Pd and Au metal gates respectively at RT. Perceptible outcomes in terms of interface trap charge density have also been presented to recognize RT H-2 sensing.