Reliability and sensitivity analysis of double inverted-T nano-cavity label-free Si:HfO2 ferroelectric junctionless TFET biosensors

Abstract

In this work, we propose and simulate an ultrasensitive, label-free, and charge/dielectric modulated Si:HfO₂ ferroelectric junctionless tunnel field effect transistor (FE-JL-TFET) based biosensor. The proposed sensing device employs a dual inverted-T cavity and uses ferroelectric gate stacking of Si-doped HfO₂, a key enabler of negative capacitance (NC) behavior. The two cavities are carved in gate-source underlap regions by a sacrificial etching technique to sense biomolecules such as streptavidin (2.1), bacteriophage T7 (6.3) and gelatin (12). Two dimensional (2D) calibrated simulations have been performed and the impact of various device parameters, including cavity length and height, on various performance measuring parameters has been studied. It has been observed that the biosensor exhibits better sensitivities for both neutral and charged biomolecules. The maximum values of the I_ON/I_OFF sensitivity for the neutral, positively charged and negatively charged biomolecules are as high as 3.77 × 10⁹, 5.85 × 10⁹, and 1.72 × 10¹⁰, respectively. It has been observed that optimizing the cavity length and height can significantly improve the sensing capability of the proposed device. The comparative analysis of the proposed biosensor and other state of the art biosensors shows a significant improvement in the sensitivity (10¹ to 10⁶ times) in the proposed biosensor. The detrimental effect of interface trapped charges on the biosensor performance is also analyzed in detail.