Modeling and Sensitivity Estimation of a Dual Cavity Source Pocket-Based Charge Plasma Tunneling FET for Label-Free Biological Molecule Detection

A dual-source cavity charge plasma tunneling FET (DSC-SP-CPTFET) with SiGe Pocket is proposed, and its effectiveness as a biological sensor for label-free detection is explored. The fabrication complexity and cost have been reduced by using the charge-plasma concept. For improved sensing, an etched nanocavity is added to the upper and lower of the source metal section. The high-k (HfO₂) gate oxide and minimal energy gap (Si_0.6Ge_0.4) alloy with a 40% mole fraction improve the current sensitivity by enhancing the drain current gradient. The sensitivity of the suggested biological sensor is assessed here for several neutral biological molecules, such as Gelatin, Keratin, Biotin, and 3-Aminopropyl-Triethoxysilane (APTES). Deoxyribonucleic acid (DNA), a charged biological molecule, is also considered with varying positive and negative charge densities. The suggested biological sensor shows a (S_IDS)_max of 2.21 × 10¹⁰ and a S_ratio of 3.11 × 10⁹ for biological molecules with higher dielectric constant at room temperature. Different electrostatic performances are estimated in the ON state, including energy band, electron (e^-) BTBT rate, electrical field, and I_DS-V_GS characteristics. In addition, the proposed biological sensor provides a much superior drain current sensitivity (S_IDS), current ratio sensitivity (S_ratio), and average SS sensitivity (S_SS) performance in the presence of both charged and neutral biological molecules.