Fabrication and characterization of thin, spin-coated, sol-gel, and colloidal silica films

Abstract

This study was conducted on both inorganic silica and organically modified silica (ormosil) films. Sol-gel derived silica films were prepared by spin-coating either a sol or a colloidal silica (COLSI) suspension mixed with a polysiloxane solution onto glass substrates. The films were microscopically investigated to reveal their structure. The optical quality of the films was measured using a scatterometer which measured the intensity of light scattered from the films as a function of angle of scatter. Scatterometry allowed the quantitative study of the factors that affect film quality, particularly film composition and number of layers spun. The effect of heating the film in-between the application of successive coatings was also investigated. Various tools were used to inspect the films, these include interferometric profilometry, probe profilometry, phase-contrast and confocal optical microscopy, and electron microscopy. Laser dyes and also various molecules possessing significant nonlinear optical properties have been successfully incorporated into the films.