Effects Of Coating Process And Charged Particles Radiation On The Structure And Optical Properties Of HfO₂ And MgF₂ Thin Films

This paper is focused on the precision of Hfo₂ and MgF₂ films thickness control prepared by vacuum physical vapor deposition（PVD）method,as well as the structure and defect evolution of the films,using ORTUS-700 coating machine,X-ray diffractometer,atomic force microscopy,X-ray photoelectron spectrum analyzer and other analytical methods.Besides,the samples prepared were irradiated by charged particles,which can provide technical support for preparing UV optical films with high peformance and evaluating their radiation resistance.The results show that the deposition temperature has obvious influence on the film thickness control.Based on the analysis of the experiment data,the statistical law of the error between quartz control and spectral control of the two kinds of thin films has been obtained,according to which the correction formula of the physical thickness is put forward.The calculation results show that the quartz control error band decreases after modification,which means an effectively improvements in the accuracy of film thickness control using quartz control method.With the increase of the depositon temperature,crystallization tendency can be noticed in both Hfo₂ and MgF₂ films.The crystallization temperature of MgF₂ films is lower and the crystallinity is higher.Besides,size of the particles,porosity factor,deoxidation and defluorination tendency of the two films increase with the increase of the deposition temperature,resulting in the the change of the films’ physical state,which leads to the decrease in spectral transmittance near the central wavelength.Besides,when moving the samples from vacuum to atmosphere,red shift of the spectrum is caused by the absorption of the gas molecules such as H 2O on the surface of the film.Proton and high energy electron irradiation experiments show that three kinds of colour centers,Pb0,Pb1,E’,are generated in Hfo₂ after irradiation,two kinds of colour centers,F,F2,are generated in MgF₂ after irradiation.The formation and accumalation of colour centers lead to absorption of light at specific wavelengths by the films,resulting in a decrease in transmittance.The radiation effects of two kinds of films is related to the radiaton source,the effect of proton is greater than that of electrons,and the high energy electrons have greater influence on glass.