Design and simulation of a germanium source dual-metal dopingless tunnel FET as a label-free biosensor

Abstract

This study presents a new dual-metal dopingless tunnel field effect transistor with a Germanium source (GeS-DM-DLT) for label-free biomolecule detection. Introducing a Ge source and dual-metal gate provides improved drain current. We have considered an L-shaped cavity at the top and bottom source metal region for investigating the sensitivity. The biosensor's sensitivity has been measured using the neutral biomolecules' dielectric constants (varying the k-values in the cavity). The sensor's DC performance is investigated using transfer characteristics, BTBT rate, energy band, and electric field variation for different k-values. The sensitivity performance of the proposed biosensor is evaluated in terms of different DC parameters (drain current, surface potential, subthreshold swing, interband tunneling rate, electric field) and RF parameters (parasitic capacitance, transconductance, cut-off frequency, maximum frequency). The suggested biosensor offers a much-improved S_ON of 9.86 × 10⁸ and S_RATIO of 1.94 × 10⁴ for a dielectric constant of 22.0 at room temperature. Further research has been done to study the effects of dielectric materials, interface trap carriers (ITC), and temperature on drain current, drain current sensitivity, and other sensitivity parameters. The article also includes investigating the influence of the fill factor on sensitivity performance. The GeS-DM-DLT sensor performs best in fully-filled conditions compared to the partially-filled condition inside the cavity region.