Study and analysis of a dielectric-modulated vertical tunnel FET biosensor using dual material gate

A bimetal gate heterogeneous dielectric vertical tunnel field-effect transistor (BG-HD-VTFET) biosensor has been investigated in this paper for the first time using engineered-gate concept, where nanogaps are introduced under tunnel gate (TG) to detect biomolecules near the device surface. To improve the detection performance of BG-HD-VTFET, an overlap is designed between source and pocket region, and the sensing ability of BG-HD-VTFET with and without overlap is compared in details. Further, an auxiliary gate (AG) is added for the proposed two devices to optimize the electrical characteristics, and the y composition of GaAs_ySb_1-y in pocket region is optimized to enhance ON-state current, and then different neutral and charged biomolecules are considered to simulate device-level gate effects. In addition, the influence of different dielectric constant at fixed charge density is studied and the length of overlap is optimized. Simulation results show that the maximum sensitivity of BG-HD-VTFET with and without overlap can reach 3.3 × 10³ and 1.9 × 10³, respectively.