Study On The Refractive Index Gradient Characteristics Of SiO_xN_y Optical Thin-film

SiO_xN_y thin-film as an important optical material.The range of refractive index is1.46~1.97,which is between the refractive index of silicon dioxide and silicon nitride film,SiO_xN_y material is widely used in the field of optical subtraction film,SiO_x N_y material is widely used in the preparation of reflective and filter thin-film.In this paper,the relationship between Si O_xN_y thin-film x,y change and refractive index was studied through MS software simulation analysis,and the relationship between the refractive index and N and O element content was obtained theoretically.Through the experiment,the evaluation criteria of the"disappearance"of SiO_xN_y gradient refractive index film interface were investigated.According to the law of SiO_xN_y thin-film x,y change and refractive index,PECVD technology was used to explore the manufacturing process of nonlinear SiO_xN_y thin-film.The results are as follows:(1)According to MS software simulation calculation of SiO_xN_y material,the results show that the refractive index of SiO_xN_y thin-film gradually decreases with the increase of O element content.The refractive index of SiO_xN_y thin-film increases gradually with the increase of N element content.When the refractive index of SiO_x N_y thin-film changes between 1.46 and1.97.PECVD technique is adopted to improve the experimental verification,the results show that the refractive index of SiO_xN_y thin-film is consistent with the experimental results of theoretical simulation.(2)The evaluation criterion of"disappearance"of the interface of SiO_xN_y gradient refractive index film depends on the manufacturing precision of the engineering application,and the?n of the film prepared by PECVD technology is less than 0.003.(3)The preparation technology of refractive index gradient films was investigated by gradient method and gradient method.The experimental results show that,continuous conversion reaction gas ratio method could be used to make gradient refractive index film.The coincidence degree of thin-film transmission rate and design curve depends on the selection of the gas proportion switching point.The transmittance curve of the thin-film is increased with the increase of the number of gradient layers,and the transmission band is also broadened.