Research On Development And Application Of High-Resolution Tomographic Imaging Mueller Matrix Ellipsometry

The structural parameters and optical properties of nanomaterials are necessary prior knowledge for the design and performance modulation of optoelectronic devices.However,due to the development trend of miniaturization,complication,and efficiency of optoelectronic devices and the limitation of the preparation process,many material structures only have micron-level lateral dimensions,which puts severe challenges to their measurement and characterization.This dissertation focuses on the goal of structural parameters and optical properties of micro-area nanomaterials,and has proposed a high-resolution tomographic imaging Mueller matrix ellipsometey based on the principle of full Mueller matrix measurement and microscopic imaging measurement.Under the premise of taking into account the high precision and accuracy of the traditional Mueller matrix ellipsometey,the developed instrument can realize full polarization information measurement with the sub-micron level lateral resolution,and has great application potential in the measurement of structural parameters and optical properties of micro-domain nanomaterials.The main research work and innovations of this paper include:The tomographic measurement principle combining full Mueller matrix measurement and back focal plane scanning is proposed,which enables the instrument to quickly change the incident angle and collect high-resolution imaging information of the sample at a wide incident angle,and realizes a wide spectrum with sub-micron lateral resolution for the first time,multiple incident angles,full Mueller matrix measurement.A mathematical model of the Mueller matrix system based on the nonlinear regression iterative algorithm is established,which realizes high accuracy and high precision ellipsometry measurement.According to the established mathematical model of the system,the source and classification of the instrument errors are analyzed,and their impact on the measurement is evaluated.Aiming at the measurement error introduced by the polarization effect of the beam splitter in the system,a parameterized calibration method based on Fourier transform is proposed to compensate the polarization effect of the beam splitter.Aiming at the measurement error introduced by the polarization effect of the high numerical aperture objective lens in the system,a parameterized calibration method based on Zernike polynomials is proposed to compensate the polarization effect of the high numerical aperture objective lens.And thus,the precise calibration of the instrument is realized.A high-resolution tomographic imaging Mueller matrix ellipsometer prototype with high ellipsometry measurement accuracy and high lateral resolution is designed and developed.Through a series of evaluation experiments,it is verified that the developed instrument has a lateral spatial resolution better than 0.8μm within full measurement band,full Mueller matrix element accuracy better than±0.005,and film thickness measurement repeatability better than±0.02 nm,which satisfies the measurement requirements of the structural parameters and optical properties of the micro area nanomaterials.The developed high-resolution tomography Muller matrix ellipsometer was used to carry out the measurement and application research of the structure size and optical constants of the micro-area nanomaterials.For the first time the characterization of the anisotropic optical constants of the micro-area nano-flake Ge S₂ and extraction of the morphological parameters of the micro-area nanostructures in the three-dimensional display were realized.In the application research process,in order to solve the problem of low contrast of the two-dimensional materials,a Hadamard imaging mode was proposed to quickly and accurately locate and identify the two-dimensional materials of the micro-domain nano-flake.For the fitting problem caused by inaccurate nanostructure period,a method of measuring period and structure parameters at the same time is proposed,which improves the accuracy of parameter extraction.The results of the application research show the excellent performance and potential application prospects of the developed instrument in the measurement of the structural parameters and optical properties of the micro-area nanomaterials.