A Comparative Analysis of Cavity Positions in Charge Plasma based Tunnel FET for Biosensor Application

Abstract

This work reports a comparative analysis of different cavity positions in Charge Plasma-based Tunnel Field Effect Transistor (CP TFET) for Biosensor Application. In CP TFET, we have created a nanogap cavity at three different positions i.e. the Source, Gate, and Drain. The nanogap cavity formed at Source, Gate, and Drain is called Source Cavity, Gate Cavity, and Drain Cavity, respectively. The intrinsic properties of biomolecules, such as dielectric constant (K) and charge density (), have been utilized to detect the biomolecules in the cavity. The source and drain region are formed by appropriate metal work functions using the charge plasma concept. The presence of biomolecules in the cavity increases the effective capacitance of the device. As a result, a high electric field generates under the cavity region. Consequently, due to large band bending, thinning of tunneling width occurred. Therefore, the increase in tunneling rate enhances the drive current of the device. The device physics has been analyzed using energy band variation, surface potential, electron tunneling rate, electric field, and transfer characteristics for different biomolecules. In addition, the Sensitivity of the device at different cavity positions has been investigated and compared in terms of ION, ION/IOFF, Vth, and SS. Furthermore, the sensitivity of the proposed device is compared with the existing literature and the possible fabrication process flow of the device has also been presented in this work.