Design and Analysis of Stair shaped cavity TFET Based Biosensor

Tunneling Field Effect Transistor (TFET), due to its lower subthreshold swing, is a promising choice for developing a biosensor with great sensitivity. In this study, we presented a TFET-based biosensor incorporating SiGe material in the source region, a highly doped n<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> pocket between the source and the channel, and, for the first time, implemented a stair-shaped cavity design. The proposed configuration enables sensitive detection of both charged and neutral biomolecules. With a novel stair-shaped cavity and a SiGe source with an n<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> pocket, our proposed biosensor shows an enhancement in drain current sensitivity. Our simulation results demonstrate an improved sensitivity of 1.4926×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> for neutral biomolecules at K=10 and 1.4043×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> for charged biomolecules at a charge density of ρ=-1×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−11</sup>. In this study, we also conducted a comparative analysis of the performance of the proposed biosensor with the conventional n<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>-doped pocket-based TFET biosensor having a uniform cavity. With the first-time non-uniform stair-shaped cavity design in our proposed biosensor, we tried to increase the gate coupling for improved band-to-band tunneling and drain current sensitivity. Therefore, with the enhancement in sensitivity, our research contributes to the ongoing efforts to create highly sensitive, label-free, fast, and accurate biomedical diagnostic tools, paving the way for revolutionary applications in healthcare, biotechnology, and various other industries.