Optimum Cavity Length of a pTFET-Based Biosensor for Successful and Accurate Sensing of a Wide Range of Biomolecules

Abstract

In this paper, for the first time, a rigorous analysis of determining minimum number of biomolecules and maximum length of the nanogap cavity, used to entrap biomolecules for the detection purpose, has been done. A pTFET-based biosensor (pTB-sensor) device is being proposed, and the corresponding detection sensitivity in terms of threshold voltage (Vth)—sensitivity, threshold voltage (Vth)—shift, subthreshold swing (SS) sensitivity, subthreshold swing (SS) shift, ON current/OFF current (ION/IOFF)—shift, leakage power (Pleak)—sensitivity is determined. It is found that the minimum number of biomolecules or minimum detection limit is 2 for Myoglobin and Apomyoglobin, while the same is 3 for Protein-G, Ferricytochrome-C, and Ferrocytochrome-C, respectively. The maximum biomolecules required for successful detection are found to be 5 for Myoglobin and Apomyoglobin, while the same is 7 for Protein-G, Ferricytochrome-C, and Ferrocytochrome-C, respectively, with 78%, 67%, 41%, 55%, and 50% Vth—sensitivity and 83%, 74%, 53%, 63%, and 58% SS sensitivity for Apomyoglobin, Myoglobin, Protein-G, Ferrocytochrome-C, and Ferricytochrome-C, respectively. This leads to the minimum cavity length of 8 nm and maximum or optimum cavity length to be 20 nm, respectively, for the detection of all the five biomolecules successfully allowing space for scaling down of the channel length to sub-100 nm technology node.