Assessment of the Biosensing Capabilities of SiGe Heterojunction Negative Capacitance-Vertical Tunnel Field-Effect Transistor

Abstract

In this study, a comparison of the negative capacitance vertical tunnel field-effect transistor (NC-VTFET) and VTFET for biosensing applications was conducted. Dielectrically modulated TFET demonstrates better sensitivity than the traditional metal oxide field effect transistor as a biosensor in label-free biosensing applications. The TFET biosensor, however, has much room for advancement by enhancing its DC characteristics. This research addresses the impact of ferroelectric gate oxide for integration of negative capacitance (NC) effect with the SiGe heterojunction pocket at the source–channel junction to enhance performance for biosensor applications. By putting the NC layer over SiO2, the channel voltage increases with decreased subthreshold slope and OFF current, thereby creating an NC effect. Because SiGe has a narrow band gap, pocket doping of SiGe near the source channel junction will increase the concentration of charge carriers, improving the band-to-band tunneling. In order to aid in the integration of biomolecules and to modulate band-to-band tunneling based on charge density (q f), dielectric constant (k), temperature, and cavity length, a cavity is additionally inserted above the source channel junction and underneath the NC layer, near to SiO2. These values were compared with and without the incorporation of NC layer with respect to various electrical properties such as drain current (I d), sensitivity, and electric field (E). According to the findings, labeled and label-free biosensors’ sensitivity may be increased by incorporating the NC effect into VTFET biosensors.