SiO_2薄膜内部短程有序微结构研究

Study on internal short-range order microstructure characteristic of SiO_2 thin film

SiO2薄膜是重要的低折射率材料之一,针对离子束溅射(IBS)和电子束蒸发(EB)的SiO2薄膜,采用红外光谱反演技术获得在400—1500 cm 1波数内的介电常数,通过对介电能损函数的分析获得了两种薄膜在横向和纵向光学振动模式下的振动频率和Si—O—Si键角.研究结果表明,在EB SiO2薄膜短程有序范围内,SiO4的连接方式主要是类柯石英结构、3-平面折叠环和热液石英结构的SiO4连接方式;在IBS SiO2薄膜短程有序范围内,SiO4的连接方式复杂主要是类柯石英结构、3-平面折叠环、4-平面折叠环结构和类热液石英结构.

SiO2 is one of important low refractive index materials, and SiO2 films are prepared by both ion-beam sputtering （IBS） and electron-beam evaporating （EB） technology. Dielectric constants of SiO2 films are calculated by infrared spectrum inversion technique in a wavenumber range from 400 cm-1 to 1500 cm-1. Through analyzing dielectric energy loss function, the oscillation frequency and the Si--O--Si angle of two types of SiO2 films are obtained in the transverse optics and longitudinal optics oscillating mode. The research results indicate that the attended modes of SiO4 are main coesite-like structure, three-plane folding ring structure, and keafite- like structure in the range of short-range order for EB-SiO2 films, but the attended modes of SiO4 are main coesite-like structure, three-plane folding ring structure, four-plane folding ring structure, and keatite-like structure in the range of short-range order for IBS-SiO2 films.