In-silico Investigation of Cyl. Gate all Around (GAA) Tunnel Field Effect Transistor (TFET) Biosensor

For some time now, the advancement of low power and high sensitivity biosensors has been the center of attention for in-situ detection and monitoring which form an integral part of portable health monitoring systems. This paper elucidates the design-optimization of a cylindrical (cyl.) gate all around (GAA) tunnel field effect transistor (TFET) biosensor with retrograde doping using numerical modeling. The device consists of n⁺ heavily doped SiGe substrate and two insulated gates i.e. primary gate (PrG) and biasing gate (BG) with suitable work functions. Sensitivity of the biosensor is investigated by varying dielectric constant (k) and charge density (ρ) in the active region of device. TFET biosensor design and simulation is performed using TCAD Synopsys software. Computations are carried out for various conditions of dielectric constant (k) and charge density (ρ) for analyzing the sensor sensitivity. Simulation results show that for k=10 and ρ = 3.0x10¹²cm⁻², there is low leakage current (I_OFF) = 1.0x10⁻¹⁶A/µm, and high ON current (I_ON) = 1.0x10⁻⁶ A/µm. Results obtained in this work as useful as it will act as a design guideline for developing TFET biosensors for various biological applications.