Polarization Angle Resolved Spectroscopy Measurement Of Quantum Dot Ultra-thin Film Under Vibration Conditions

The rapid development of the photovoltaic field,new energy,and micro-nano manufacturing fields has made the industry's demand for high-luminous efficiency and high-stability luminescent materials more extensive.Ultra-thin films made from quantum dot materials have shown a fiery development as an emerging material.prospect.At present,the deposition of coated quantum dots through atomic layer deposition(ALD)technology is expected to become the mainstream production process in the future.In the production process of the quantum dot ultra-thin film prepared by this technology,the thickness of the quantum dot ultra-thin film has a decisive influence on its luminescence performance,and the realization of online measurement of the ultra-thin film thickness plays an important role in improving the product yield.The existing ultra-thin film measurement methods are sensitive to vibration conditions in actual production,and it is difficult to achieve accurate online measurement.Based on the polarization angle-resolved spectral reflectance technology,this subject has designed a set of ultra-thin film thickness online measurement system.Aiming at the problem of the sample defocusing due to the vibration of the equipment and affecting the measurement accuracy in the actual workshop production,this paper proposes an error compensation method under the defocus measurement,which solves the problem of the decrease of the film measurement accuracy caused by the vibration defocusing.It provides a new solution for the accurate measurement of ultra-thin film thickness in non-focused state.The research of this article is mainly divided into the following parts:First,a simulation analysis of the imaging of the Polarization Angle Resolution Measurement System(PARS)in the defocused state is carried out.A simulation model of the PARS system was established by Zemax to simulate the back focal plane imaging in the defocused state,and finally the simulation analysis curve of the maximum radius of the back focal plane image R?max and the defocus amount (?) when defocused was obtained.Second,it is verified that the defocus will cause serious errors in the measurement results of the PARS system.After some improvements to the original system and readjustment,the back focal plane image of the film sample is obtained,and the ellipsometric parameters at different incident angles are extracted from it to realize the inversion of the film thickness,and the average error of the thickness measurement in the focal state< 2.2%;The ellipsometric parameters extracted under different defocusing amounts are quite different,and the average error of the measurement results is 20.89%.Last,it realizes angular distortion compensation and ellipsometric parameter error compensation under different defocusing amounts.The problem of angular distortion in the defocused state in the experiment is proposed,and the Brewster angle is used to calibrate the angle under different defocusing amounts to achieve the corresponding angle compensation and eliminate the angular distortion;on this basis,a standard sample The ellipsometric parameter is used as the calibration value to determine the ellipsometric parameter compensation amount under each defocus amount,and a lookup table of the ellipsometric parameter error compensation amount related to the defocus amount and the incident angle in two dimensions is established,which improves the measurement accuracy in the defocus state The average error of the measurement results is less than 1.4%,which realizes the rapid online measurement of ultra-thin films under vibration and defocusing conditions.