Determination of the Bimetallic Layers' Film Thicknesses by Phase Detection of SPR Prism Coupler

In this paper, the phase detection method is demonstrated to determine the film thicknesses of bimetallic layers by surface plasmon resonance (SPR) prism coupler. It was proposed and developed by matching the experimental results to the theoretical curves of the phase difference with different angles of incidence. The results of both of the two metallic film thicknesses obtained by our method coincide well with the measurement results of atomic force microscope (AFM) and spectroscopic ellipsometer (SE) measurement. Both theoretical analysis and experimental results indicate that the method proposed is stable and reliable, and feasible to be used to determine the film thickness of bimetallic layers directly with nanometer order resolution.