Method for measuring absorption coefficient of metallic TiNx film

Abstract

The invention relates to a method for measuring the absorption coefficient of a metallic TiNx film. The method comprises the following steps: firstly, carrying out cathode luminescence (CL) tests under different voltages at the same positions of a P-GaN substrate and P-GaN coated with a metallic TiNx film with the thickness of about 50nm to obtain corresponding cathode luminescence intensity; secondly, obtaining absorption coefficients of the TiNx film under different voltages according to the Lambert's law, and further obtaining an average absorption coefficient value; and finally, testing the square resistance of the film by using a four-probe technology, and further determining the metallicity of the TiNx film. According to the invention, SEM and CL are combined to obtain the absorptioncoefficient of the metallic TiNx film, so that a new method for measuring the absorption coefficient of a metallic film with the thickness of dozens of nanometers on a semiconductor substrate is provided.

Description

technical field [0001] The invention relates to a method for measuring the absorption coefficient of a thin film, in particular to a metallic TiN x Measurement method of film absorption coefficient. Background technique [0002] Titanium Nitride (TiN x ) is a refractory non-stoichiometric transition metal nitride with a melting point as high as 2930 ° C. The metallic TiNx is golden yellow and exhibits plasmonic excitation behavior in the visible and near-infrared spectral ranges. Compared to conventional plasmonic materials such as gold and silver, TiN x It has a series of advantages such as high melting point, good chemical stability, high mechanical strength, corrosion resistance, biocompatibility, and easy integration with standard silicon-based technology, and TiN x The optical properties of TiN are tunable with the change of growth parameters, therefore, TiN x Become a plasmonic ceramic material that replaces the traditional precious metal material gold, marking a n...

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Problems solved by technology

It is reported in the literature that the ellipsometric parameters of TiNx films are usually measured by ellipsometry, including the total amplitude and phase of the reflected light on the surface of the film and each interface, so as to fit the optical parameters such as the refractive index and extinction coefficient of the film. However, in our test , we find that when the metallic TiN x When the thickness of the film reaches tens of nanometers, due to the metallic TiN x The specular reflection and absorption of light by the thin film makes it difficult to correctly fit the optical parameters of the thin film

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