Surface film plasmon resonance-based metal film measuring device and method

Abstract

The invention discloses a surface film plasmon resonance-based metal film measuring device. The device comprises an isosceles right-angle prism. The bottom surface of the isosceles right-angle prism is orderly coated with a submicron-thickness dielectric film and a metal film to be tested and then the isosceles right-angle prism is immersed in a solution. Through rotation of a launch arm of an ellipsometer by a certain angle, the angle of incident lights to the interface between the isosceles right-angle prism and the dielectric film is greater than the total reflection critical angle of the interface, the excited surface plasmon resonance conditions are satisfied and the plasmon resonance on the excited surface of the metal film to be detected is realized. The light amplitude ratios Psi and phase difference Delta corresponding to different wavelengths are measured, the relation curve between the amplitude ratios Psi and phase difference Delta, and the incident wavelengths is fitted, and the thickness and the optical constant of the metal film to be detected is calculated through inversion. The device has the advantages of adjustability of resonance center wavelength, wide detection range of metal film thickness and few fitting parameters and has a large application potential in the field of accurate characterization of the optical constant of the ultrathin film and the detection of biochemical substance composition.

Description

Technical field [0001] The invention relates to a metal film measuring technology, in particular to a metal film measuring device and a measuring method based on surface plasmon resonance. Background technique [0002] Surface plasmon resonance technology can be used to measure the optical constants of metal thin films. At present, the structures commonly used to excite surface plasmon resonance are Kretschmann structure and Otto structure, but these two structures have their own shortcomings and are limited in practical applications. In the Kretschmann structure, the metal film to be measured is plated on the bottom of the right-angle prism, and the incident light enters through one right-angle surface of the right-angle prism, and exits from the other right-angle surface of the prism after being reflected by the bottom surface of the prism. However, in the Kretschmann structure, the thickness range of the metal film to be tested is limited, and the center wavelength correspond...

AI Technical Summary

Problems solved by technology

In the Otto structure, the thickness of the air gap is difficult to accurately control, so the thickness of the air gap needs to be fitted during the fitting process, and the repeatability of the measurement results of this structure is poor, which affects the characterization accuracy of the optical constants of the metal film

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