Wang Lishuan

Optical Constants of SiO2 Films Deposited on Si Substrates

SiO2 films were deposited on single-crystalline silicon substrates by ion beam sputtering technology. Optical constants of SiO2 films are calculated from spectroscopic ellipsometry data, transmittance spectra and reflectance spectra by WVASE32 software, and the best fitted method is obtained for calculating optical constants of dielectric materials in the ultraviolet-visible-infrared (UV-VIS-IR) range. In the UV-VIS-NIR spectral range, refractive indices of SiO2 films are calculated separately by both ellipsometry data and reflectance spectra, and the obtained results are almost the same. Complex dielectric functions of SiO2 films in the IR spectral range are accurately calculated with infrared transmission spectra using the GenOsc model. The obtained accuracy complex refractive index of SiO2 films in the wavelength region from 0.19 μm to 25 μm is of great importance for the design of high quality coatings, such as ultra-low loss coating.

Adjustments of refractive index and stress of SiO2 films prepared by IBS technology

基于正交试验方法,系统研究了用离子束溅射法制备SiO2薄膜其折射率、应力与工艺参数(基板温度、离子束压、离子束流和氧气流量)之间的关联性.使用分光光度计和椭圆偏振仪测量SiO2薄膜透过率光谱和反射椭偏特性,利用全光谱反演计算法获得薄膜的折射率,通过测量基底镀膜前后的表面变形量得到SiO2薄膜的应力.实验结果表明,工艺参数对薄膜折射率影响权重从大到小依次为氧气流量、基板温度、离子束流和离子束压,前三者对折射率影响的可信概率分别为87.03％、71.98％和69.53％;对SiO2薄膜应力影响权重从大到小依次为基板温度、离子束压、氧气流量和离子束流,前三者对应力影响的可信概率分别为95.62％、48.49％和37.88％.得到的结果表明,制备低折射率SiO2薄膜应选择高氧气流量、低基板温度和低离子束流;制备低应力SiO2薄膜应选择低基板温度和高氧气流量.