Control Technology Of Uniformity Of Optical Thin Films Deposited By PECVD

PECVD (Plasma Enhanced Chemical Vapor Deposition),with the aid of glow discharge plasma,is the preparation technology that makes gas with film materials reacted to deposit film material.By controlling the membrane preparation process parameters,the influence of each process parameters on heterogeneity of optical thin film of different refractive index materials is obtained.The research resultss of controlling technology on the uniformity of optical thin films by PECVD is researched,method to control inhomogeneous optical film during preparation process is studied,it is meaningful for technique application of optical thin film by PECVD technology.The thin films are deposited by PECVD on B270(Φ150mm) glass and silicon substrate.The paper studies the high refractive index,middle and low refractive index optical thickness uniformity of film,analyzes the influence of different process parameters on the optical thickness uniformity of film.The results shows that optical thin film deposition by PECVD with the range of150mm diameter,the uniformity of the film refractive index is superior to the geometric thickness,optical thickness nonuniformity is mainly derived from the distribution of the geometric thickness.Using optimum deposition optical thin film,when the high refractive index thin films are deposited by zhe best process parameters,the average refractive index is1.87(550nm),the average geometric thickness is106nm,the Optical thickness nonuniformity is3.9%;when the middle refractive index thin films are deposited by zhe best process parameters,the average refractive index is1.47(550nm),the average geometric thickness of195 nm,the Optical thickness nonuniformity is4.7%;when the low refractive index thin films are deposited by zhe best process parameters,the average refractive index is1.40(550nm),the average geometric thickness of137nm,the Optical thickness nonuniformity is4.6%.