Ge Pocket-Based Dual Gate Tunnel FET: A Label-Free Biosensor

In this work, we designed and simulated a novel dielectrically modulated (DM) dual-metal-gate tunnel field effect transistor (DMG-TFET). The proposed TFET can efficiently facilitate the label-free detection of biomolecules and can work as a label-free biosensor. It employs a highly doped Germanium pocket with an optimized pocket length of 5 nm in the channel region near the source side. Besides, an enhanced on-current (<i>I</i> _ON) is achieved in our proposed device owing to the introduction of a pocket and the use of a high dielectric constant <i>k</i>, as well as a dual-metal gate. The proposed TFET sensor features twin cavities within the gate oxides to sense biomolecules. The sensitivity of the biosensor is evaluated based on its ability to detect biomolecules using their inherent material parameters, such as dielectric constant (<i>k</i>) and charge density (ρ). The proposed DMG-TFET is compared to the conventional dielectrically modulated FET in terms of sensitivity for different values of dielectric constants (<i>k</i>). It has been found that the sensitivity of the proposed biosensor is 10⁴ times greater than that of the conventional device at <i>k</i> = 10 and ρ = 0. Special cases of sensitivity have been analyzed for a single biomolecule of uricase (<i>k</i> = 1.54) placed at various positions and orientations. It has been observed that the biomolecule's position in the cavity has a significant effect on the sensor's performance. All results are deduced from simulations carried out on Silvaco Atlas. To observe the effect of noise on the biosensor's sensitivity, noise-aware sensitivity estimation and detection analysis have been performed.