Gate-all-around junctionless FET based label-free dielectric/charge modulation detection of SARS-CoV-2 virus

Ultra Sensitive Breast Cancer Cell Lines Detection Using Dual Nanocavities Engraved Junctionless FET

This article reports breast cancer cell lines (Hs578T, MDA-MB-231, MCF-7, and T47D) and healthy breast cells (MCF-10A) detection based on the modulation of its electrical properties by deploying dual nanocavity engraved junctionless FET. The device has a dual gate to enhance gate control and has two nanocavities etched under both gates for breast cancer cell lines immobilization. As the cancer cells are immobilized in the engraved nanocavities, which were earlier filled with air, the dielectric constant of the nanocavities changes. This results in the modulation of the device's electrical parameters. This electrical parameters modulation is then calibrated to detect the breast cancer cell lines. The reported device demonstrates a higher sensitivity toward the detection of breast cancer cells. The JLFET device optimization is done for improving the performance by optimizing the nanocavity thickness and the SiO2 oxide length. The variation in the dielectric property of cell lines plays a key role in the detection technique of the reported biosensor. The sensitivity of the JLFET biosensor is analyzed in terms of ∆VTH, ∆ION, ∆gm , and ∆SS . The reported biosensor shows the maximum sensitivity for T47D ( κ = 32 ) breast cancer cell line with ∆VTH = 0.800 V, ∆ION = 0.165 mA/μm, ∆gm = 0.296 mA/V-μm , and ∆SS = 5.41 mV/decade. Moreover, the effect of variation in the occupancy of the cavity by the immobilized cell lines has also been studied and analyzed. With increased cavity occupancy the variation in the device performance parameter enhances Further, the sensitivity of the proposed biosensor is compared with the existing biosensors and it is reported to be highly sensitive as compared to the existing biosensors. Hence, the device can be utilized for array based screening of cell lines of breast cancer and diagnosis with the benefit of easier fabrication and cost effectiveness of the device.

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

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.

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.