Abstract: A method for measuring a thickness and optical constants of a multi-layer film comprises the following steps: 1: depositing films on a substrate to form a multi-layer film; 2: measuring an ellipsometric spectrum of the multi-layer film; 3: when the film layer of the multi-layer film is the diamond film, step 41 is executed; when the film layer of the multi-layer film is the diamond-like film, steps 42, 5, and 6 are executed; 41: obtaining optical constants and a thickness of the film layer of the multi-layer film; 42: selecting a spectral region defining a transparent section of the film layer of the multi-layer film, and obtaining optical constants and a thickness of the film layer of the multi-layer film; 5: adjusting an amplitude and a width of an oscillator model according to the ellipsometric spectrum; and 6: evaluating a difference between an experimental value and a fitted value.

Abstract: First, it is judged whether the diamond film is the single-crystal diamond film or the polycrystalline diamond film according to ellipsometric spectrum data and absorption spectrum data, and different calculation methods are selected to obtain the optical constants and the thickness of the diamond film according to spectral data (e.g., the ellipsometric spectrum data and the absorption spectrum data). Additionally, in the single-crystal diamond film, the optical constants and the thickness of the diamond film are obtained through calculation using the Cauchy model. In the polycrystalline diamond film, the spectral region is selected, and the optical constants and the thickness of the diamond film are obtained through calculation according to the oscillator model and the evaluation function MSE.