<p>This work introduces four novel biosensors based on surface plasmon resonance (SPR) by employing silicon (Si), gallium nitride (GaN), and silicon nitride (Si<InlineEquation ID="IEq1"> <EquationSource Format="TEX">\({}_{3}\)</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mn>3</mn> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>N<InlineEquation ID="IEq2"> <EquationSource Format="TEX">\({}_{4}\)</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mn>4</mn> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>) over thin films of Silver (Ag) and bimetallic Gold (Au)/Silver (Ag) layers. These biosensors are compatible with CMOS technology and offer high refractive indices, low optical losses, stability, and biocompatibility for accurate detection of analytes in different biomedical fields. These proposed biosensor structures are categorized as BS-1A and BS-1B with Ag films and BS-2C and BS-2D with bimetallic Au and Ag films. The optimized configurations are BK7-Ag(50nm)-Si(6nm)-GaN(1nm)-Biosample and BK7-Ag(50nm)-Si(6nm)-(Si<InlineEquation ID="IEq3"> <EquationSource Format="TEX">\({}_{3}\)</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mn>3</mn> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>N<InlineEquation ID="IEq4"> <EquationSource Format="TEX">\({}_{4}\)</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mn>4</mn> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>)(2nm)-Biosample, BK7-Au (26 nm) and BK7-Au(26nm)-Ag(26nm)-Si(6nm)-(Si<InlineEquation ID="IEq5"> <EquationSource Format="TEX">\({}_{3}\)</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mn>3</mn> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>N<InlineEquation ID="IEq6"> <EquationSource Format="TEX">\({}_{4}\)</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mn>4</mn> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>)(1nm)/Biosample, respectively. The biosensor’s performance is evaluated using the finite element method in COMSOL Multiphysics. By testing biosensors for Sensitivity (S) and creating a Figure of Merit (FoM), it is clear that the proposed structures work better than conventional ones, increasing sensitivity by 3.166 times. Calculated S (<InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(^\circ \)</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation>/RIU) and FoM (1/RIU) are 400, 420, 420, 380, and 80.80, 90.322, 92.307, and 75.509. The proposed biosensor was also validated for urine glucose detection, showing a sensitivity exceeding 323 <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(^\circ \)</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation>/RIU. These innovative biosensors exhibit excellent performance in biomedical applications with high sensitivity and rapid response regarding resonance angle shift.</p>