Preparation of Silica Nanospheres:Effect of Silicon Alkoxide and Alcohol on Silica Nanospheres

摘要

Special attention has recently been paid to methods for controlling the nanospheres' size and distribution,because they exhibit peculiar and desirable properties in the wafer polishing process.Monodisperse silica nanospheres were first synthesized by Stober et al.using the sol-gel method,which induces high purity in the resulting particles.Bogush and Zukoski reported the influence of reaction parameters such as ammonia and water contents on the particles' size and distribution.They observed that,for a particular concentration of tetraethylorthosilicate (TEOS) with ethanol as solvent,particle size reaches a maximum and then decreases as both ammonia and water concentrations are increased.Similar behavior was observed for all the TEOS concentrations studied,and the maximum particle size moved to higher ammonia and water concentrations as the TEOS concentration was increased.The maximum monodisperse size achievable by this process was found to be 800 nm.While narrow size distributions were achievable by this process,the solid content of the resulting dispersion was less than 2 wt.%.Attempts to increase solid content by simply increasing the initial TEOS concentration for a particular concentration of ammonia and water resulted in larger particle sizes and broader size distributions.