<p>This work provides the theoretical study of a highly sensitive Kretschmann-configured SPR biosensor for the detection of SARS-CoV-2 virus. The proposed optimal model consists of seven layers—prism (BK-7)/Ag/Si₃N₄/Franckeite/BaTiO₃/ssDNA/sensing medium. Herein, five structures (from Structure-I to Structure-V) with different layered configurations are analyzed for getting the optimal model. The electromagnetic behavior of these models is studied for the SARS-CoV-2 virus as a sensing medium with varying refractive index (RI) from 1.334 to 1.355, representing the viral concentration (0–525&#xa0;mM). Performance of these sensor structures is investigated in terms of sensitivity (S), quality factor (QF), detection accuracy (DA), figure of merit (FOM), and contrast sensitivity function (CSF) using the angular interrogation method. The sensor structure model with functional layers—Ag/Si₃N₄/Franckeite/BaTiO₃—shows highest sensitivity of 347.7°/RIU. This sensor structure is proposed to be utilized for the detection of SARS-CoV-2 virus with lower concentrations.</p> Graphical Abstract <p></p>