Performance Analysis of Dielectric-Modulated C-Shaped Pocket Dual-Gate Metal-Stacked Oxide-Sandwiched Drain TFET-Based Biosensor

Abstract

The article examines the performance of a C-shaped dual-gate metal-stacked oxide-sandwiched drain TFET (CSP-DGM-SO-SD TFET) designed for label-free biosensing applications. Key design considerations such as dual nanocavity placement, a C-shaped pocket region, a sandwiched drain architecture, and stacked oxide engineering are employed to enhance the tunneling probability, thereby increasing the drain current and improving overall sensing performance. The proposed device operates as a dielectric-modulated label-free biosensor by integrating a nanocavity beneath the gate electrode to capture target biomolecules and modulate the device electrostatics accordingly. Using 2D Sentaurus TCAD simulations across various dielectric constants (K = 1.54, 3.57, 6.3, 8, 12), the study evaluates important DC parameters such as ON-state current (ION), average subthreshold swing (SSavg), and current-switching ratio (CSR) to explore the fundamental device physics of the CSP-DGM-SO-SD TFET’s ability to detect both charged and neutral biomolecules. The CSP-DGM-SO-SD TFET biosensor exhibits outstanding performance, achieving an ION sensitivity of 2.24 × 108 and CSR sensitivity of 6.47 × 108 for the detection of gelatin (K = 12). More effective band-to-band tunneling is made possible by an increase in the dielectric constant, which intensifies the electric field inside the tunneling area. As a result, the device’s overall sensitivity is increased, and its drain current is increased. Next, for the CSP-DGM-SO-SD TFET biosensor at K = 12, the impact of steric hindrance is analyzed using partially filled nanocavities with fill factors of 42% and 60% with various step patterns. The influence of irregular probe placement on ON-state current sensitivity is also examined through TCAD simulations to capture nonideal device behavior. Overall, the proposed biosensor demonstrates high sensitivity and reliable detection of diverse biomolecules, making it suitable for advanced label-free biosensing applications.