Dielectric engineered charge plasma assisted JFTFET SARS-CoV-2 sensor for rapid assessment of respiratory disorder: proposal and investigation

Abstract

Dielectric engineered (DE) field-effect transistors (FETs) have become quite popular for label-free detection of biomolecules. Nevertheless, the intrinsic short-channel effects restrict their scalability, sensitivity, and energy optimization. Consequently, to achieve the full capability of the DEFET-based biosensors, an effort to quickly identify biomarkers for the SARS-CoV-2 virus is being commenced for the first time. This utilizes a highly expandable, exceptionally sensitive, and energy-saving DE charge plasma assisted junction free tunnel FET (DE-CPA-JFTFET). The proposed architecture enables the incorporation of a nanogap cavity at the source end within the gate oxide via targeted etching, offering stability to the immobilized biomolecules. Affordable diagnostic techniques are essential to curb the transmission of infectious illnesses, including COVID-19. Utilizing the envelope, spike, and DNA proteins of the virus, a comprehensive examination of the sensitivity of the proposed sensor has been conducted by measuring the change in drain current and threshold voltage using calibrated TCAD simulations. Presence of the composite biomolecules in the nanogaps are characterized by the effective dielectric constant (k = 4, 10, 12) of the virus proteins including the DNA charge density variation ranging from \(- \,2 \times 10^{12}\) to \(+ \,2 \times 10^{12} \,{\text{C}}/{\text{cm}}^{2}\). Present findings suggest that the proposed DE-CPA-JFTFET demonstrates an exceptionally high threshold voltage sensitivity (S_VTH) of 31.50, ON-state current sensitivity (S_ION) of \(\sim \,459.76\), a high I_ON/I_OFF exceeding seven orders of magnitude, sub-threshold swing (SS) of \(\sim \,10\,{\text{mV}}/{\text{dec}}\), making it a potential alternative to traditional FET-based biosensors. Moreover, the proposed DE-CPA-JFTFET sensor has also been analyzed by investigating the transient behavior of the drain current.