Dual metal dual layer GAA NW–FET (DMDL–GAA–NW–FET) biosensor for label free SARS-CoV-2 detection

The current Covid-19 epidemic has necessitated the development of a biosensor that is expected to be extraordinarily sensitive, rapid, precise, and economical for the detection of the SARS-CoV-2 virus. This paper proposes a novel structure named Dual Metal Dual Layer Gate-All-Around Nanowire Field Effect Transistor (DMDL-GAA-NW-FET) Biosensor for detection of SARS-CoV-2 in terms of the S (Spike) protein and DNA of the virus using the concept of dielectric modulation and charge modulation. The proposed device employs gate work function engineering to segregate the gate into two layers with two distinct work functions, improving gate control. As a result, the biosensor's capability to identify the SARS-CoV-2 virus is significantly improved. Analysis of the proposed device's electrostatic behavior in terms of channel potential, energy band variation and electron concentration has been performed and then SARS-CoV-2 viral detection has been validated using the threshold voltage drift (ΔV_TH), I_ON current drift (ΔI_ON), g_m, I_ON/I_OFF ratio and g_d upon virus immobilization in the nanocavity. The effectiveness of the DMDL-GAA-NW-FET biosensor in detecting SARS-CoV-2 is further highlighted by a comparison of the biosensor's threshold voltage and I_ON current sensitivities with those of a conventional Gate-All-Around Nanowire FET (GAA-NW-FET) biosensor.